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Article  文章

Distinguishing between Deep-Water Sediment Facies: Turbidites, Contourites and Hemipelagites
区分深水沉积相:浊积岩、轮廓流沉积物和半盆地沉积物

Dorrik Stow and Zeinab Smillie *(D)
Dorrik Stow 和 Zeinab Smillie *(D)
Institute of Geo-Energy Engineering, Heriot-Watt University, Edinburgh EH14 4AS, Scotland, UK; d.stow@hw.ac.uk
英国苏格兰爱丁堡赫瑞瓦特大学地质能源工程研究所,邮编 EH14 4AS;d.stow@hw.ac.uk
* Correspondence: z.smillie@hw.ac.uk; Tel.: +44-131-451-3845
* 通讯作者:z.smillie@hw.ac.uk;电话:+44-131-451-3845

Received: 28 August 2019; Accepted: 23 January 2020; Published: 13 February 2020
收到日期:2019 年 8 月 28 日;接受日期:2020 年 1 月 23 日;发表日期:2020 年 2 月 13 日

Abstract  摘要

The distinction between turbidites, contourites and hemipelagites in modern and ancient deep-water systems has long been a matter of controversy. This is partly because the processes themselves show a degree of overlap as part of a continuum, so that the deposit characteristics also overlap. In addition, the three facies types commonly occur within interbedded sequences of continental margin deposits. The nature of these end-member processes and their physical parameters are becoming much better known and are summarised here briefly. Good progress has also been made over the past decade in recognising differences between end-member facies in terms of their sedimentary structures, facies sequences, ichnofacies, sediment textures, composition and microfabric. These characteristics are summarised here in terms of standard facies models and the variations from these models that are typically encountered in natural systems. Nevertheless, it must be acknowledged that clear distinction is not always possible on the basis of sedimentary characteristics alone, and that uncertainties should be highlighted in any interpretation. A three-scale approach to distinction for all deep-water facies types should be attempted wherever possible, including large-scale (oceanographic and tectonic setting), regional-scale (architecture and association) and small-scale (sediment facies) observations.
在现代和古代深水系统中,浊积岩、轮廓沉积物和半陆相沉积物之间的区分长期以来一直存在争议。这部分原因是这些过程本身作为一个连续体存在一定程度的重叠,因此其沉积特征也相互重叠。此外,这三种相类型通常出现在大陆边缘沉积物的互层序列中。这些端元过程的性质及其物理参数正变得更加清楚,本文在此简要总结。过去十年中,在识别端元相在沉积结构、相序列、生痕相、沉积物质地、成分和微构造方面的差异也取得了良好进展。本文根据标准相模型及自然系统中常见的这些模型变异,对这些特征进行了总结。然而,必须承认,仅凭沉积特征并不总能实现明确区分,任何解释中都应强调存在的不确定性。 应尽可能尝试对所有深水相类型采用三尺度区分方法,包括大尺度(海洋学和构造环境)、区域尺度(构造和组合)以及小尺度(沉积相)观察。

Keywords: turbidites; contourites; hemipelagites; deep-water systems; facies; continental margin deposits; ichnofacies; sediment textures; microfabric
关键词:浊积岩;轮廓流沉积物;半盆地沉积物;深水系统;相;大陆边缘沉积物;生痕相;沉积物质地;微构造

1. Introduction  1. 引言

1.1. Complexity and Controversy
1.1. 复杂性与争议

There is a wide range of processes that operate in deep water to erode, transport and deposit sediment. These include a variety of gravity-driven (or downslope), current-driven (or bottom-current), pelagic (or vertical settling) and chemogenic processes. Each of these processes gives rise to a distinctive deposit or sediment facies. Comprehensive reviews of these processes and their deposits have been compiled recently in [1-3]. The authors of these works also illustrate the growing number of synonyms and partial synonyms in current use which tend to confuse rather than aid understanding. In this paper we focus on turbidity currents, bottom currents and pelagic settling, as well as the deposits of these.
深水环境中存在多种作用过程,用以侵蚀、搬运和沉积沉积物。这些过程包括各种重力驱动(或下坡)、洋流驱动(或底流)、远洋(或垂直沉降)以及化学成因过程。每种过程都会形成独特的沉积物或沉积相。关于这些过程及其沉积物的综合综述,近期已在文献[1-3]中汇编。上述著作的作者还指出,目前使用的同义词和部分同义词数量不断增加,反而容易引起混淆而非促进理解。本文重点讨论浊流、底流和远洋沉降及其沉积物。
However, there are many subtleties in both process and facies, meaning the picture is more complex, and, hence, controversy arises. Firstly, there are several different types and scales of turbidity current and bottom current, with each of these being able to transport and modify everything from coarse sand and gravel to fine silt and clay-sized material. Both turbidity currents and bottom currents carry (finer) sediment as suspended load and transport (coarser) sediment via bed-load traction across
然而,无论是过程还是相貌,都存在许多细微差别,这意味着情况更加复杂,因此也引发了争议。首先,浊流和底流有多种不同类型和规模,每种类型都能搬运和改造从粗砂砾到细粉砂和粘土大小的物质。浊流和底流都以悬浮负载携带(较细的)沉积物,并通过床载牵引在海底搬运(较粗的)沉积物。

the seafloor. Secondly, there is a continuum between these different processes and facies, which are therefore end-members on a natural spectrum of process and deposit (Figure 1).
其次,这些不同的过程和相貌之间存在连续性,因此它们是过程和沉积物自然谱系上的端元(图 1)。

Figure 1. Processes and facies in deep-water sedimentary systems. (A) Downslope, Modified from [4]; (B) Alongslope and vertical settling.
图 1. 深水沉积系统中的过程和相貌。(A) 斜坡向下,改编自[4];(B) 斜坡沿向和垂直沉降。
The processes of sediment transport and deposition in the natural environment rarely conform to a particular end-member of that spectrum, meaning the deposit will not fit exactly the idealised facies model. Thirdly, all three types can be closely interbedded, particularly in continental margin sedimentary successions. Strong bottom currents are capable of reworking earlier-deposited sediments, winnowing and eroding the sea-floor and of preventing deposition, thereby causing hiatuses and/or hardgrounds in the sediment record. Turbidity currents are equally able to erode or modify seafloor sediments. Pelagic or hemipelagic sedimentation dominates where other processes are absent or rare, but all trace of these deposits can be absent or removed where turbidites dominate or where strong bottom currents have prevented deposition and created a widespread hiatus in sedimentation.
自然环境中的沉积物运输和沉积过程很少完全符合该范围的某个极端端元,这意味着沉积物不会完全符合理想化的相模型。第三,三种类型的沉积物常常紧密互层,尤其是在大陆边缘的沉积序列中。强烈的底流能够重塑早期沉积的沉积物,筛选和侵蚀海底,并阻止沉积,从而在沉积记录中造成间断和/或硬地层。浊流同样能够侵蚀或改变海底沉积物。浮游或半浮游沉积在其他过程缺失或罕见的地方占主导地位,但当浊积岩占主导地位或强烈的底流阻止沉积并造成广泛的沉积间断时,这些沉积的所有痕迹可能会缺失或被移除。
It is in part for these reasons that the distinction between turbidites, contourites and hemipelagites in modern and ancient deep-water systems has long been a matter of controversy [5,6]. The debate is further fuelled by a plethora of published literature that seeks to provide a definitive interpretation of ancient sediment series, either on land or in deep subsurface cores, on the basis of insufficient evidence. There remain, therefore, markedly different sets of criteria published in the literature for distinguishing between the different deep-water facies [7]. Anyone whose work involves deep-water systems and their sediments should be aware of these differences in opinion.
部分原因在于此,现代和古代深水系统中浊积岩、轮廓沉积物和半陆相沉积物之间的区分长期以来一直存在争议[5,6]。这一争论还因大量文献试图基于不足的证据对陆地或深层地下岩心中的古沉积序列做出明确解释而进一步加剧。因此,文献中仍存在明显不同的标准用于区分不同的深水相[7]。任何从事深水系统及其沉积物研究的人都应了解这些不同的观点。

1.2. A Brief History
1.2. 简史

An extensive body of work on deep-water processes and sediments has been built over the past 150 years since the voyage of HMS Challenger (1872-1876), during which the first systematic study of seafloor sediments was made [8,9]. For many decades since that pioneering expedition, and through the first half of the twentieth century, the deep sea was considered entirely pelagic in nature. Some of the major advances made in understanding pelagic and hemipelagic deposits, both on the present-day seafloor and in ancient deposits on land, have been summarised by [10].
在过去的 150 年里,自 HMS Challenger 号航行(1872-1876 年)以来,关于深水过程和沉积物的广泛研究逐步建立起来,在此期间首次对海底沉积物进行了系统研究[8,9]。在那次开创性远征后的几十年里,直到二十世纪上半叶,深海一直被认为完全是远洋性质的。[10]总结了在理解现今海底和陆地古老沉积物中的远洋和半远洋沉积物方面取得的一些重大进展。
Turbidites were first recognised in the 1950s [11] and the first facies model was developed in [12]. Since that time, turbidites have been one of the better known and most intensively studied deep-water sediment facies. They are now very well known from sediment cores recovered from modern deep-water systems, subsurface (hydrocarbon) boreholes and ancient outcrops now exposed on land. Each new study of a particular turbidite system reveals specific deposit characteristics and facies for that system. The most commonly observed facies have been variously synthesised into a range of facies schemes proposed by [1,2,13-19], amongst others.
浊积岩最早于 20 世纪 50 年代被识别[11],首个相模型于[12]中提出。自那时起,浊积岩成为较为知名且研究最为深入的深水沉积相之一。如今,通过从现代深水系统采集的沉积岩芯、地下(碳氢化合物)钻孔以及现今陆地上暴露的古老露头,浊积岩已被广泛了解。每一项针对特定浊积岩系统的新研究都会揭示该系统的特定沉积特征和相。最常见的相已被[1,2,13-19]等人综合归纳为多种相方案。
Contourites were first identified a decade later in the early 1960s by Bruce Heezen and co-workers at Woods Hole Oceanographic Institute, USA. The now seminal paper of [20] demonstrated the very significant effects of contour-following bottom currents in shaping sedimentation on the deep continental rise off eastern North America. The deposits of these semi-permanent alongslope currents soon became known as contourites, and the first clear facies models were put forward in [21,22]. The demarcation of slope-parallel, elongate and mounded sediment bodies made up largely of contourites became known as contourite drifts [23,24].
等深流沉积物最早于十年后,即 20 世纪 60 年代初,由美国伍兹霍尔海洋研究所的 Bruce Heezen 及其同事们发现。[20]这篇现已成为经典的论文展示了沿等深线流动的底层洋流在塑造北美东部大陆坡深水沉积中的极其重要作用。这些半永久性沿坡流的沉积物很快被称为等深流沉积物,首批明确的相模型在[21,22]中提出。由主要由等深流沉积物组成的坡平行、细长且隆起的沉积体的划分被称为等深流漂积体[23,24]。

1.3. Synthesis and Distinction
1.3. 综合与区分

This paper aims to provide a state-of-the-art synthesis of turbidites, contourites and hemipelagites in a fast-moving field of research. It draws on diverse published literature over the past two decades and on synthesis work by the current authors on turbidites [17,25,26] and contourites [17,27-31]. We then propose a methodology and set of criteria for the distinction between the different deposits.
本文旨在对浊积岩、等深流沉积物和半盆地沉积物这一快速发展的研究领域进行最先进的综合。它借鉴了过去二十年间多样的已发表文献,以及当前作者关于浊积岩[17,25,26]和等深流沉积物[17,27-31]的综合研究成果。随后,我们提出了一套区分不同沉积物的方法论和标准。

2. Deep-Water Processes  2. 深水过程

2.1. Turbidity Currents  2.1. 浊流

As noted above, it is important to recognise that turbidity currents are part of a process continuum across the spectrum of processes [17]. Mass transport events (e.g., slides and slumps) in
如上所述,重要的是要认识到浊流是一个过程连续体的一部分,涵盖了各种过程[17]。近岸坡地区的质量搬运事件(如滑坡和崩塌)

proximal slope regions may evolve downslope into debris flows and thence into turbidity currents (Figure 2). Low-concentration turbidity currents can feed material into semi-permanent bottom currents, or, through a process of dilution and flow lofting (Figure 3), lead to a process of hemiturbiditic settling [32,33]. This sort of evolution is part of downslope flow transformation [1]. In addition, gravitational transformation within individual flow events, especially those that are coarse-grained and high-concentration, leads to internal stratification due to vertical gravity segregation. Both types of transformation can result in composite beds with abrupt textural breaks, known as hybrid beds [1,34-37], or in the separation of the flow into two parts, yielding spatially separated deposits.
可能沿坡向下演变成碎屑流,进而演变成浊流(图 2)。低浓度的浊流可以将物质输送到半永久性的底流中,或者通过稀释和流体抬升的过程(图 3),导致半浊积沉降过程[32,33]。这种演变是坡向下流动转化的一部分[1]。此外,单个流动事件中的重力转化,尤其是那些粗粒和高浓度的流动,会由于垂直重力分离而导致内部分层。这两种转化都可能形成具有突变纹理界面的复合层,称为混合层[1,34-37],或者导致流体分离成两部分,形成空间分离的沉积物。

Figure 2. Schematic view (partial 3D) of a turbidity current, identifying the head, body and tail regions. High-concentration flows commonly develop a distinctive dense basal layer towards the flow front.
图 2. 浑浊流的示意图(部分三维),标示出流头、流体和流尾区域。高浓度流通常在流前端形成一个独特的致密底层。

Figure 3. Schematic view (2D) of the flow-lofting process at the most distal end of a turbidity current. Deposition of distal mud turbidites and hemiturbidites as shown. Modified from [32].
图 3. 流动悬浮过程的示意图(二维),位于浑浊流最远端。显示了远端泥质浑浊岩和半浑浊岩的沉积。改编自[32]。
Within this spectrum of processes, turbidity currents are one of the most important ways by which fine, medium and coarse-grained material are transferred from shallow to deep water. They are turbulent suspensions of mud and sand (and gravel in some cases) in water which are propelled by the downslope component of gravity acting on the excess density. They may occur as (a) relatively short-lived surge events that travel for only a matter of kilometres downslope or (b) relatively long-lived uniform or steady flows. Surge events may evolve into uniform flows through a process of flow ignition such that an autosuspension process [38] of self-maintenance is generated in the flow. Alternatively, they may be fed by a steady discharge due to prolonged input from, for example, a hyperpycnal flow [39,40]. The uniform flow type permits very long distance transport over tens to several thousands of kilometres, both downslope, over gradients of > 5 > 5 > 5^(@)>5^{\circ} to < 0.5 < 0.5 < 0.5^(@)<0.5^{\circ}, and across flat abyssal plains. They can even travel a certain distance in an upslope direction before they come to a halt by a combination of frictional resistance, loss of sediment from the base of the flow and reverse gravitational pull as the flow moves upslope.
在这一系列过程中,浊流是将细粒、中粒和粗粒物质从浅水区输送到深水区的最重要方式之一。浊流是在水中由泥沙(在某些情况下还有砾石)组成的湍流悬浮体,其动力来源于重力沿坡度方向作用于过剩密度的分量。浊流可以表现为(a)相对短暂的突发事件,仅沿坡度方向移动数公里,或(b)相对持久的均匀或稳定流动。突发事件可能通过流动点火过程演变为均匀流动,从而在流动中产生自维持的自动悬浮过程[38]。另外,它们也可能由持续输入(例如超密流[39,40])所维持的稳定排放供给。均匀流动类型允许物质沿坡度方向在数十至数千公里的距离上长距离运输,坡度范围从 > 5 > 5 > 5^(@)>5^{\circ} < 0.5 < 0.5 < 0.5^(@)<0.5^{\circ} ,并可跨越平坦的深海平原。 它们甚至可以在上坡方向上行进一定距离,然后由于摩擦阻力、流动底部沉积物的流失以及流体上坡移动时的反向重力作用而停止。
Turbidity current properties are becoming better known from observational and experimental data [41-46] coupled with theoretical modelling [47-49], although there is still a range of uncertainty over some estimates. Based on a considerable volume of earlier work [16,17,50-56], as well as more recent studies, we can summarise the principal properties as follows (see also [1,26]. Flow velocities have been calculated at 5 25 m s 1 5 25 m s 1 5-25ms^(-1)5-25 \mathrm{~m} \mathrm{~s}^{-1} for coarse-grained high-concentration flows, and may exceed 25 m s 1 25 m s 1 25ms^(-1)25 \mathrm{~m} \mathrm{~s}^{-1} in some cases. At the other end of the spectrum, fine-grained low-concentration flows may travel for many hundreds of kilometres at velocities < 0.5 m s 1 < 0.5 m s 1 < 0.5ms^(-1)<0.5 \mathrm{~m} \mathrm{~s}^{-1}. Flow concentration also shows a wide range of values, although this is much more difficult to measure precisely. High-concentration turbidity currents show concentrations of 100 500 kg m 3 100 500 kg m 3 100-500kgm^(-3)100-500 \mathrm{~kg} \mathrm{~m}^{-3}; above these concentrations they can be referred to as other types of sediment gravity flow (e.g., concentrated density flow, inflated sandflow and debris flow) [1]. Powerful events can result in fast and dense near-bed layers connected to seabed remobilization [43]. At the low end of the spectrum, large dilute mud-rich turbidity currents have very low concentrations of around 0.025 2.5 kg m 3 0.025 2.5 kg m 3 0.025-2.5kgm^(-3)0.025-2.5 \mathrm{~kg} \mathrm{~m}^{-3}.
浊流的特性正通过观测和实验数据[41-46]以及理论模型[47-49]变得更加清晰,尽管某些估计仍存在一定的不确定性。基于大量早期研究[16,17,50-56]以及近期的研究,我们可以总结出主要特性如下(参见[1,26])。粗粒高浓度流的流速已被计算为 5 25 m s 1 5 25 m s 1 5-25ms^(-1)5-25 \mathrm{~m} \mathrm{~s}^{-1} ,在某些情况下可能超过 25 m s 1 25 m s 1 25ms^(-1)25 \mathrm{~m} \mathrm{~s}^{-1} 。在另一端,细粒低浓度流可能以 < 0.5 m s 1 < 0.5 m s 1 < 0.5ms^(-1)<0.5 \mathrm{~m} \mathrm{~s}^{-1} 的速度行进数百公里。流体浓度也表现出广泛的变化范围,尽管这更难以精确测量。高浓度浊流的浓度为 100 500 kg m 3 100 500 kg m 3 100-500kgm^(-3)100-500 \mathrm{~kg} \mathrm{~m}^{-3} ;超过该浓度时,它们可被称为其他类型的沉积重力流(例如,浓缩密度流、膨胀砂流和碎屑流)[1]。强烈事件可能导致快速且密集的近床层,与海底再动员相关联[43]。 在低端范围内,大型稀释的富含泥质的浊流浓度非常低,约为 0.025 2.5 kg m 3 0.025 2.5 kg m 3 0.025-2.5kgm^(-3)0.025-2.5 \mathrm{~kg} \mathrm{~m}^{-3}
Individual turbidity currents are discrete events with very variable recurrence intervals ( 10 0 10 5 y 10 0 10 5 y 10^(0)-10^(5)y10^{0}-10^{5} \mathrm{y} ) and of very different sizes. The largest flows are known to overtop channel margins in excess of 500 m in height on many of the large elongate fans (e.g., Bengal, Indus, Amazon and Laurentian). These flows are likely to be several kilometres in width and probably tens of kilometres in length. Much smaller turbidity currents also occur in, for example, lakes and reservoirs. Turbidity currents can be channel-confined or flow across open slopes with little apparent confinement. They can deposit beds between < 0.01 m < 0.01 m < 0.01m<0.01 \mathrm{~m} and > 10 m > 10 m > 10m>10 \mathrm{~m} in thickness. Mean accumulation rates, therefore, are also very variable, being typically from 0.1 m to > 1 m ka 1 > 1 m ka 1 > 1mka^(-1)>1 \mathrm{~m} \mathrm{ka}^{-1}. The frequency of the occurrence of turbidity currents ranges from 1 ka (approximately) for the distal Bengal fan to one every few years for parts of the Amazon and Congo fan systems, or more frequently still for offshore active rivers and in some lacustrine environments.
单个浊流是离散事件,复发间隔( 10 0 10 5 y 10 0 10 5 y 10^(0)-10^(5)y10^{0}-10^{5} \mathrm{y} )变化很大,规模也各不相同。已知最大流量在许多大型狭长扇体(如孟加拉、印度、亚马逊和劳伦琴扇)上超过 500 米高的通道边缘。这些流量宽度可能达到数公里,长度可能达到数十公里。更小的浊流也发生在例如湖泊和水库中。浊流可以受通道限制,也可以在开阔坡面上流动,几乎没有明显限制。它们可以沉积厚度在 < 0.01 m < 0.01 m < 0.01m<0.01 \mathrm{~m} > 10 m > 10 m > 10m>10 \mathrm{~m} 之间的地层。因此,平均沉积速率也非常不稳定,通常从 0.1 米到 > 1 m ka 1 > 1 m ka 1 > 1mka^(-1)>1 \mathrm{~m} \mathrm{ka}^{-1} 不等。浊流发生的频率从孟加拉远端扇体的大约 1 千年一次,到亚马逊和刚果扇系统部分地区每隔几年一次,甚至在近海活跃河流和某些湖泊环境中更频繁。
Hemiturbiditic sedimentation [32,33] involves flow lofting and upward dispersion from a dilute turbidity current during its final stages of deposition and/or following interaction with a positive topographic obstacle. The fine-grained material carried by the turbidity current disperses above and beyond the final deposit of the normal turbidite, mixes with any background pelagic or hemipelagic material, and deposits slowly by vertical settling. Deposition is episodic (geologically an event deposit) but accumulation is sufficiently slow that a restricted ichnofaunal bioturbation continues throughout. Insufficient data exist to estimate mean rates of accumulation.
半浊积沉积[32,33]涉及在浊流沉积的最后阶段和/或与正地形障碍物相互作用后,流体的抬升和向上扩散。浊流携带的细粒物质在正常浊积物最终沉积物之上及更远处扩散,与任何背景的远洋或半远洋物质混合,并通过垂直沉降缓慢沉积。沉积是间歇性的(地质学上为事件沉积),但积累速度足够缓慢,以至于有限的生迹动物扰动持续存在。现有数据不足以估算平均积累速率。

2.2. Bottom Currents  2.2. 底流

There are at least three different bottom current types that can be recognised as operating in deep-water settings [6,57,58], including (a) wind-driven bottom currents, (b) thermohaline bottom currents and © deep-water tidal bottom currents, both barotropic and baroclinic. Internal waves (including baroclinic tides) oscillate along the interface between two water masses of different densities.
在深水环境中至少可以识别出三种不同类型的底流[6,57,58],包括(a) 风驱动底流,(b) 热盐底流,以及(c) 深水潮汐底流,后者包括等密性和非等密性两种。内波(包括非等密性潮汐)沿着两种不同密度水体的界面振荡。
These are common throughout the oceans but are especially marked and energetic at the depth of the thermocline [59]. Bottom currents are also affected by intermittent processes such as giant eddies, benthic storms, flow cascading and tsunamis (Figure 4). All of these currents and processes are capable of affecting seafloor sediment through their erosion, transport and deposition [6,60-65]. Based on a large volume of work, as summarised in these papers, their principal characteristics are as follows.
这些洋流在全球海洋中普遍存在,但在温跃层深度处尤为显著且活跃[59]。底层洋流还受到间歇性过程的影响,如巨型涡旋、底层风暴、流体级联和海啸(图 4)。所有这些洋流和过程都能通过侵蚀、搬运和沉积作用影响海底沉积物[6,60-65]。基于大量研究工作,并在这些论文中进行了总结,其主要特征如下。

Figure 4. Schematic view (3D) of a bottom (contour) current, identifying the current core, eddies and strands within a deep-water mass. Typical physical parameters as shown. Modified from [63].
图 4. 底层(等深线)洋流的示意图(3D),标示了洋流核心、涡旋和深水体内的流线。显示了典型的物理参数。改编自[63]。

2.2.1. Thermohaline and Wind-Driven Bottom Currents
2.2.1. 热盐环流和风驱动底层洋流

The principal characteristics of both thermohaline and wind-driven bottom currents are similar, particularly with regard to how they most affect seafloor erosion and contourite deposition [6,28,29,57,62,64]. They are semi-permanent features in the ocean basins, often long-lived through geological time. They act continuously in affecting sedimentation, rather than as episodic turbidity current events, as described above. They have a net flow alongslope but can also flow upslope, downslope and around and over topographic obstacles or irregularities. After generation near the surface in the source area, they cascade downslope until they find the appropriate density layer for their salinity-temperature properties. At this level they turn, under the influence of the Coriolis force, to flow alongslope.
热盐环流和风驱底流的主要特征相似,尤其是在它们如何最显著地影响海底侵蚀和轮廓沉积方面[6,28,29,57,62,64]。它们是海洋盆地中的半永久性特征,通常在地质时间尺度上存在时间较长。它们持续不断地影响沉积过程,而非如上文所述的间歇性浊流事件。它们沿坡面有净流动,但也可以逆坡、顺坡流动,或绕过并越过地形障碍或不规则地形。在源区近海面生成后,它们沿坡面下滑,直到达到适合其盐度-温度特性的密度层。在该层次上,在科里奥利力的作用下,它们转向沿坡面流动。
Bottom currents show (a) broad sluggish movement of water (mean velocity < 0.1 m s 1 < 0.1 m s 1 < 0.1m*s^(-1)<0.1 \mathrm{~m} \cdot \mathrm{~s}^{-1} ) over low gradient slopes and in ocean basins, (b) more constricted intermediate velocity flows ( 0.1 0.3 m s 1 0.1 0.3 m s 1 0.1-0.3m*s^(-1)0.1-0.3 \mathrm{~m} \cdot \mathrm{~s}^{-1} ) over steeper slopes and around topographic obstacles and © highly constricted high velocity flows ( > 0.3 m s 1 > 0.3 m s 1 > 0.3m*s^(-1)>0.3 \mathrm{~m} \cdot \mathrm{~s}^{-1} ) through narrow gateways and passages and over shallow sills. These velocities may exceed 1 m s 1 1 m s 1 1m*s^(-1)1 \mathrm{~m} \cdot \mathrm{~s}^{-1} where the flow is particularly restricted or the slope especially steep (nearly 3 m s 1 3 m s 1 3m*s^(-1)3 \mathrm{~m} \cdot \mathrm{~s}^{-1} has been measured in the Gibraltar Gateway, for example). Mean flow velocity decreases from the core to the margins of the current. Flow velocity is directly affected by changes in slope gradient and other topographic irregularities along its course, and also by current meandering and subdivision into two or more strands around obstacles. Flow concentration is still poorly known but is almost certainly several orders of magnitude lower than those of turbidity currents. Estimates show a range of 0.025 0.25 g m 3 0.025 0.25 g m 3 0.025-0.25gm^(-3)0.025-0.25 \mathrm{~g} \mathrm{~m}^{-3}, with a tenfold increase under benthic storm conditions (see below).
底流表现为:(a) 在低坡度斜坡和海洋盆地上水体的广泛缓慢运动(平均速度 < 0.1 m s 1 < 0.1 m s 1 < 0.1m*s^(-1)<0.1 \mathrm{~m} \cdot \mathrm{~s}^{-1} ),(b) 在较陡斜坡和地形障碍物周围更受限制的中等速度流动( 0.1 0.3 m s 1 0.1 0.3 m s 1 0.1-0.3m*s^(-1)0.1-0.3 \mathrm{~m} \cdot \mathrm{~s}^{-1} ),以及(c) 通过狭窄通道和浅水堰的高度受限高速流动( > 0.3 m s 1 > 0.3 m s 1 > 0.3m*s^(-1)>0.3 \mathrm{~m} \cdot \mathrm{~s}^{-1} )。当流动特别受限或坡度特别陡峭时,这些速度可能超过 1 m s 1 1 m s 1 1m*s^(-1)1 \mathrm{~m} \cdot \mathrm{~s}^{-1} (例如,在直布罗陀通道测得的速度接近 3 m s 1 3 m s 1 3m*s^(-1)3 \mathrm{~m} \cdot \mathrm{~s}^{-1} )。平均流速从流心向流边缘递减。流速直接受坡度变化和沿途其他地形不规则性的影响,同时也受流体绕过障碍物时的摆动和分流成两股或多股的影响。流体浓度仍知之甚少,但几乎可以肯定比浊流低几个数量级。估计显示范围为 0.025 0.25 g m 3 0.025 0.25 g m 3 0.025-0.25gm^(-3)0.025-0.25 \mathrm{~g} \mathrm{~m}^{-3} ,在底栖风暴条件下增加十倍(见下文)。
Bottom currents are highly variable in location, direction and velocity over relatively short timescales (from hours to months). Velocity increase, decrease and flow reversal occur as a result of deep tidal effects. Seasonal changes can result from variation in properties of the water masses generated in the source regions. Large eddies develop at the flow margins, where they peel off and
底流在相对较短的时间尺度内(从数小时到数月)在位置、方向和速度上变化极大。速度的增加、减少以及流向的反转都是深层潮汐效应的结果。季节性变化则可能源于源区水团性质的变化。大型涡旋在流动边缘形成,并在此处脱离,进而

move at high angles or in a reverse direction to the main flow. Eddy kinetic energy, sea-surface topographic variations and surface current instabilities can all be transmitted through the water column and so result in a marked variation in kinetic energy imparted to the seafloor. Such variation can lead to an alternation of short (days to weeks) episodes of higher velocity benthic storms, and longer periods (weeks to months) of lower velocity. Benthic storms can result in further erosion and resuspension of large volumes of sediment, the incorporation of this sediment into the bottom current as suspended sediment load and transport downstream. Deposition occurs during the quieter low-velocity periods. Bottom currents also show longer-period variability (from decadal to millennial), with some of this being able to be attributed to changes in climate and sea-level, for example at the scale of Milankovitch cyclicity, e.g., [66,67].
以高角度或与主流方向相反的方向移动。涡旋动能、海面地形变化和表层洋流不稳定性都可以通过水柱传递,从而导致传递到海底的动能显著变化。这种变化可能导致短期(数天到数周)高速度底层风暴与较长时间(数周到数月)低速度阶段交替出现。底层风暴会引起进一步的侵蚀和大量沉积物的再悬浮,这些沉积物被纳入底流作为悬浮沉积物负载并向下游运输。沉积则发生在较为平静的低速阶段。底流还表现出较长周期的变异(从十年到千年),其中部分变异可归因于气候和海平面变化,例如米兰科维奇周期尺度的变化,[66,67]。

2.2.2. Deep-Water Tidal Bottom Currents
2.2.2. 深水潮汐底流

The specific characteristics of tidal currents in deep water are less well known [6,60]. They have been a continuous process throughout geological time, with a distinctive tidal periodicity. This can lead to alternating normal and reverse current directions and to periods of higher and lower velocity. The focussing effect of deep-ocean channels and gateways leads to maximum current velocities of 0.25 0.5 m s 1 0.25 0.5 m s 1 0.25-0.5ms^(-1)0.25-0.5 \mathrm{~m} \mathrm{~s}^{-1} in many slope canyons down to water depths of at least 4600 m , and maximum current velocities as high as 0.75 m s 1 0.75 m s 1 0.75ms^(-1)0.75 \mathrm{~m} \mathrm{~s}^{-1} in some cases. These flows may operate at right angles to alongslope bottom currents. However, where the tidal bottom current is directed in parallel with alongslope bottom currents, for example through contourite channels or gateways, the tidal component is added to the alongslope bottom current [68]. This may serve to alternately increase and decrease the mean bottom-current velocity.
深水潮流的具体特征尚不十分清楚[6,60]。潮流在地质时期内一直是一个持续的过程,具有独特的潮汐周期性。这可能导致正常和反向流向交替出现,以及流速的高低变化。深海通道和通道的聚焦效应使得许多坡谷中的最大流速达到 0.25 0.5 m s 1 0.25 0.5 m s 1 0.25-0.5ms^(-1)0.25-0.5 \mathrm{~m} \mathrm{~s}^{-1} ,水深至少达到 4600 米,某些情况下最大流速甚至高达 0.75 m s 1 0.75 m s 1 0.75ms^(-1)0.75 \mathrm{~m} \mathrm{~s}^{-1} 。这些流动可能与沿坡底流垂直。然而,当潮汐底流与沿坡底流平行时,例如通过轮廓流通道或通道,潮汐成分会叠加到沿坡底流中[68]。这可能导致平均底流速度交替增加和减少。

2.3. Pelagic and Hemipelagic Settling
2.3. 浮游和半浮游沉降

Pelagic settling is a process of vertical settling under the influence of gravity by which primary biogenic material and very fine-grained terrigenous or other detritus in the surface waters fall slowly to the seafloor. The rate of fall and hence of sediment accumulation is increased by both flocculation and by organic pelletisation, especially in high productive areas. In oligotrophic open-ocean systems, the process is quite continuous and accumulation is typically very slow, i.e., < 1 cm ka 1 < 1 cm ka 1 < 1cmka^(-1)<1 \mathrm{~cm} \mathrm{ka}^{-1}. However, in high productive margin areas, the process can occur as pulsed blooms or be seasonal [69]. In this case, sediment is mainly deposited during the onset of eutrophic periods where flocculation of blooming primary producers and production of large faecal pellets by growing zooplankton are favoured.
浮游沉降是一种在重力作用下的垂直沉降过程,表层水中的初级生物源物质以及非常细粒的陆源或其他碎屑物缓慢沉降到海底。沉降速度及沉积速率因絮凝作用和有机颗粒化作用而增加,尤其是在高生产力区域。在贫营养的开阔海洋系统中,该过程相当连续,沉积通常非常缓慢,即 < 1 cm ka 1 < 1 cm ka 1 < 1cmka^(-1)<1 \mathrm{~cm} \mathrm{ka}^{-1} 。然而,在高生产力的大陆边缘区域,该过程可能以脉冲性藻华或季节性形式发生[69]。在这种情况下,沉积主要发生在富营养期的开始阶段,此时有利于初级生产者的絮凝和生长中的浮游动物产生大量粪便颗粒。
Hemipelagic deposition [70] is a complex process involving both vertical settling and slow lateral advection through the water column (Figure 5). The driving forces behind this lateral advection include the inertia of river plumes (both within the water column and at the surface), glacial meltwater diffusion, turbid layer plumes, internal tides and waves and other slowly moving midwater currents. Cross-shelf and/or shelf-to-slope advection of selected fine particles, seafloor re-suspension and off-shelf spillover of fluid mud may also contribute to this process [71]. Between 1000 and 2000 m water depth, modern slope sediments are generally enriched in organic carbon older than 1000-2000 years. Hemipelagic deposition is a continuous process with very variable rates depending on the nature of biogenic and terrigenous inputs, e.g., 2 cm ka 1 2 cm ka 1 2cmka^(-1)2 \mathrm{~cm} \mathrm{ka}^{-1} on continental margins with little terrigenous input, 10 cm ka 1 10 cm ka 1 10cm*ka^(-1)10 \mathrm{~cm} \cdot \mathrm{ka}^{-1} for black shale hemipelagites in areas of high upwelling and over 20 cm ka 1 20 cm ka 1 20cm*ka^(-1)20 \mathrm{~cm} \cdot \mathrm{ka}^{-1} for high latitude glaciomarine hemipelagites.
半陆源沉积[70]是一个复杂的过程,涉及垂直沉降和通过水柱缓慢的横向平流(图 5)。驱动这种横向平流的力量包括河流羽流的惯性(既存在于水柱中也存在于水面上)、冰川融水扩散、浑浊层羽流、内潮和波浪以及其他缓慢移动的中层水流。选定细颗粒的跨陆架和/或陆架至陆坡的平流、海底再悬浮以及流体泥的陆架外溢也可能对这一过程有所贡献[71]。在 1000 至 2000 米水深之间,现代陆坡沉积物通常富含年龄超过 1000-2000 年的有机碳。半陆源沉积是一个连续的过程,其速率因生物源和陆源输入的性质而异,例如, 2 cm ka 1 2 cm ka 1 2cmka^(-1)2 \mathrm{~cm} \mathrm{ka}^{-1} 在陆源输入较少的大陆边缘, 10 cm ka 1 10 cm ka 1 10cm*ka^(-1)10 \mathrm{~cm} \cdot \mathrm{ka}^{-1} 在高上升流区域的黑色页岩半陆源沉积物中,以及 20 cm ka 1 20 cm ka 1 20cm*ka^(-1)20 \mathrm{~cm} \cdot \mathrm{ka}^{-1} 在高纬度冰川海洋半陆源沉积物中。

Figure 5. Schematic view (3D) of the hemipelagic and pelagic processes, identifying sediment supply from terrigenous and biological sources as well as its dispersion and settling through the water column. Typical physical parameters as shown.
图 5. 半深海沉积和远洋沉积过程的示意图(3D),显示了陆源和生物源沉积物的供应及其在水柱中的扩散和沉降。图中展示了典型的物理参数。

2.4. Flow Transformation, Process Interaction and Reworking
2.4. 流动转变、过程相互作用与再加工

As already noted, flow transformations commonly occur within turbidity currents and related mass gravity flows via downslope evolution of flow type (debris flow to high-concentration turbidity current to low-concentration turbidity current to a flow-lofted turbidity cloud) and via gravitational within-flow segregation (debris flow, turbidity current and grain flow alternation) [1,34,72-74].
如前所述,流动转变通常发生在浊流及相关的重力流中,通过流型的下坡演变(碎屑流到高浓度浊流,再到低浓度浊流,最后到流动悬浮的浊云)以及流内的重力分选(碎屑流、浊流和颗粒流交替)实现[1,34,72-74]。
Close interaction between different processes is also common (e.g., [ 1 , 17 , 57 , 60 , 61 ] [ 1 , 17 , 57 , 60 , 61 ] [1,17,57,60,61][1,17,57,60,61] ). Both turbidity currents and bottom currents will directly affect the slow settling of hemipelagic material, incorporating this fine-grained, often biogenic, material into their deposits. Bottom currents will similarly pirate the fine suspended load of distal turbidity currents [60] and of the upper parts of flows that have over-spilled channel levees. The sudden introduction of turbidity current material into bottom currents will affect the nature and concentration of the flow as well as the composition of the deposit. Both interbedded and hybrid facies will result. Deep tidal currents have the potential to interact with and modify the properties (e.g., velocity) of thermohaline and wind-driven bottom currents, especially where their velocity is enhanced in restricted passageways or channels [68].
不同过程之间的密切相互作用也很常见(例如, [ 1 , 17 , 57 , 60 , 61 ] [ 1 , 17 , 57 , 60 , 61 ] [1,17,57,60,61][1,17,57,60,61] )。浊流和底流都会直接影响半深海沉积物的缓慢沉降,将这些细粒、常为生物源的物质纳入其沉积物中。底流同样会掠夺远端浊流[60]及溢出河道堤岸上部流体的细悬浮物。浊流物质突然进入底流会影响流体的性质和浓度以及沉积物的组成,导致夹层和混合相沉积的形成。深潮流有可能与热盐环流和风驱动底流相互作用并改变其特性(如速度),尤其是在受限通道或河道中其速度增强的情况下[68]。
Downslope turbidity currents, alongslope bottom currents and deep tidal currents have the potential to rework any previously deposited sediment on the seafloor. The extent of reworking, the distance of transport as bedload and the degree of resuspension and incorporation into the over-riding flow will depend on both the properties of the flow (speed, capacity and competence) and the nature of the sediment (grain-size, competence and consolidation).
下坡浊流、沿坡底流和深海潮流都有可能重新搬运海底先前沉积的沉积物。重新搬运的范围、作为床载体的运输距离以及再悬浮和纳入上覆流体的程度,将取决于流体的性质(速度、运载能力和搬运能力)以及沉积物的性质(粒径、搬运能力和固结程度)。

3. Turbidite Deposits  3. 浊积物沉积物

3.1. Definition and Turbidite Facies
3.1. 定义与浊积物相

Turbidites are defined as all those sediments deposited by turbidity currents. They are geologically instantaneous event deposits, although the deposition of a single turbidite bed may take minutes
浊积物被定义为所有由浊流沉积的沉积物。它们是地质上瞬时事件的沉积物,尽管单层浊积物床的沉积可能需要几分钟时间。

(gravels and coarse sands) to a few days (fine silts and muds). Turbidites have been one of the better known and most intensively studied deep-water sediment facies since they were first recognised in the 1950s [11] and the first facies model was developed in [12]. They are now very well known from sediment cores recovered from modern deep-water systems, subsurface (hydrocarbon) boreholes and ancient outcrops exposed on land. They include a very wide range of deposit types, from very thin-bedded ( < 3 cm < 3 cm < 3cm<3 \mathrm{~cm} ) silt-mud layers to very thick-bedded ( 1 10 m 1 10 m 1-10m1-10 \mathrm{~m}, rarely more) graded gravel-sand-mud units.
(砾石和粗砂)到几天(细粉砂和泥)。自 20 世纪 50 年代首次被识别以来,浊积岩一直是较为知名且研究最为深入的深水沉积相之一[11],首个沉积相模型也在[12]中提出。如今,通过从现代深水系统、地下(碳氢化合物)钻孔以及陆地上暴露的古老露头中采集的沉积岩芯,浊积岩已被广泛了解。它们包括非常广泛的沉积类型,从非常薄层( < 3 cm < 3 cm < 3cm<3 \mathrm{~cm} )的粉砂-泥层到非常厚层( 1 10 m 1 10 m 1-10m1-10 \mathrm{~m} ,极少超过此数)的分级砾石-砂-泥单元。
There are very many different individual turbidite facies recognised. The most common of these have been variously synthesised into a range of facies schemes proposed by [1,2,13-19], amongst others. We show the principal facies models for turbidites in Figures 6-12. The deposit characteristics, as described below, are illustrated with photographs in Figures 7, 9 and 12. They are based on a long and extensive history of turbidite study and publications, as synthesised in [1,2,13-17,75-77], amongst others.
已识别出许多不同的单一浊积岩沉积相。其中最常见的被不同学者综合归纳为一系列沉积相方案,如[1,2,13-19]等人所提出。我们在图 6-12 中展示了浊积岩的主要沉积相模型。下文描述的沉积特征通过图 7、9 和 12 中的照片加以说明。这些模型基于长期且广泛的浊积岩研究和出版物,综合于[1,2,13-17,75-77]等文献。

Figure 6. The coarse-grained turbidite family for gravel, pebbly sand and sandy turbidites. The ideal Lowe facies model showing the complete sequence of divisions R2-S3 [78], and typical partial sequences found commonly in nature, is given.
图 6. 砾石、卵砾砂和砂质浊积岩的粗粒浊积岩系列。理想的 Lowe 相模型展示了完整的 R2-S3 分层序列[78],以及自然界中常见的典型部分序列。

Figure 7. Cont.  图 7. 续。
Figure 7. Coarse-grained turbidite/debrite family: photographic examples. (A) Very thick-bedded structureless sandstone turbidite succession (deep-water massive sands), Carpathian Flysch, Romania. (B) Clast-supported conglomerate turbidite with clast-alignment and erosive, reverse-graded base, Dana Point, California. © Shale-clast-rich sandstone, turbidite-debrite transition, Carmelo, California. (D) Sandy, matrix-supported conglomerate (to boulder-rich sandstone) non-cohesive debrite, Tabernas Basin, SE Spain. (E) Matrix-supported cohesive debrite, near Benidorm, SE Spain. (F) Deep-water massive sandstone turbidite with water-escape dish-structures, Cantua Basin, California. (G) Deep-water massive sandstone turbidite, structureless, Peira Cava, SE France. (H) Deep-water massive sandstone turbidite, structureless, with patchy grain-size variation, Peira Cava, SE France.
图 7. 粗粒浊积岩/碎屑岩系列:照片示例。(A) 非常厚层的无结构砂岩浊积岩层序(深水巨厚砂),喀尔巴阡飞地岩,罗马尼亚。(B) 碎屑支撑的砾岩浊积岩,具有碎屑排列和侵蚀性逆级配基底,加利福尼亚 Dana Point。(C) 富含页岩碎屑的砂岩,浊积岩-碎屑岩过渡,加利福尼亚 Carmelo。(D) 砂质、基质支撑的砾岩(至富含巨砾砂岩)非胶结碎屑岩,西班牙东南部 Tabernas 盆地。(E) 基质支撑的胶结碎屑岩,西班牙东南部 Benidorm 附近。(F) 具有水逃逸碟状结构的深水巨厚砂岩浊积岩,加利福尼亚 Cantua 盆地。(G) 无结构的深水巨厚砂岩浊积岩,法国东南部 Peira Cava。(H) 无结构且具有斑驳粒度变化的深水巨厚砂岩浊积岩,法国东南部 Peira Cava。

3.2. Turbidite Characteristics
3.2. 浊积岩特征

Bedding. Turbidites generally show very well-defined bedding. Distinct beds with sharp bases and sharp to gradational tops are the norm. Interbedding of well-defined sandstone and mudstone beds is one of the distinctive characteristics by which turbidites are recognised. Individual beds vary widely in thickness, from < 1 cm < 1 cm < 1cm<1 \mathrm{~cm} to > 10 m > 10 m > 10m>10 \mathrm{~m}, whereas the frequency of bed thickness typically follows a power-law distribution in many turbidite successions.
层理。浊积岩通常表现出非常清晰的层理。具有清晰基底和从尖锐到渐变顶面的明显层理是常态。清晰的砂岩层与泥岩层交错出现,是识别浊积岩的一个显著特征。单个层理的厚度变化很大,从 < 1 cm < 1 cm < 1cm<1 \mathrm{~cm} > 10 m > 10 m > 10m>10 \mathrm{~m} 不等,而在许多浊积岩层序中,层理厚度的频率通常遵循幂律分布。
Structures. Primary sedimentary structures indicative of deposition by unidirectional currents are very common, especially in thin- to thick-bedded turbidites. These include parallel and cross-lamination/bedding, lenticular and discontinuous lamination (in thin and very thin beds) and spaced to indistinct lamination (in thick and very thick beds). Large-scale cross-bedding or dune-cross-bedding is rare, except where it occurs by flow by-passing on the channel floor. Parts of beds as well as whole beds may be entirely structureless, at least to the naked eye. This is especially true for thick and very thick beds, which may also show well-developed water-escape structures (pipes, dishes and convolute lamination) indicative of very rapid deposition. The bases of beds commonly show loads, flame structures and scours (flutes and grooves). Sedimentary structures are typically organised systematically into sequences through normally-graded beds. These form the basis of the turbidite facies models described below.
结构。指示单向流沉积的原生沉积结构非常常见,尤其是在薄层至厚层浊积岩中。这些结构包括平行层理和交错层理/层理、透镜状和不连续层理(出现在薄层和极薄层中)以及间隔层理到模糊层理(出现在厚层和极厚层中)。大规模的交错层理或沙丘交错层理较为罕见,除非发生在通道底部的流体绕流处。部分岩层甚至整个岩层可能完全无结构,至少肉眼无法辨认。厚层和极厚层尤其如此,这些岩层还可能显示发育良好的排水结构(管状、盘状和卷曲层理),表明沉积速度非常快。岩层基底通常显示负载结构、火焰结构和冲刷痕迹(凹槽和沟槽)。沉积结构通常系统地组织成通过正常分级岩层的序列。这些构成了下文所述浊积岩相模型的基础。
Bioturbation. Turbidites commonly develop a top-down ichnofacies, reworking the upper parts of a bed while leaving the lower parts unaffected. Bioturbation is best developed where the repeat frequency of turbidite events is relatively low, meaning the turbidites are interbedded with more slowly-accumulated hemipelagites and/or contourites. Detailed studies have revealed distinctive ichnofacies for different turbidite settings [79-82]. In a submarine fan environment, thick-bedded sandstones of channel axes are characterised by low-intensity and low-diversity Ophiomorpha and Thalassinoides ichnofacies. Intensity of burrowing and diversity of the assemblage increases across the channel margin (Pychosiphon-Thalassinoides ichnofacies) to the overbank-levee environments. In these thin-bedded sand-mud turbidites, a diverse Planolites-Chondrites ichnofacies dominates. In a slope apron environment, typified by the Nereites ichnofacies, bioturbation is generally more intense and diverse. The Ophiomorpha sub-ichnofacies (with Diplocriterion and Scolicia) characterises the mid-upper slope turbidites, whereas the Paleodictyon sub-ichnofacies characterises the distal slope.
生物扰动。浊积岩通常形成自上而下的生痕化石群,重塑地层的上部而不影响下部。生物扰动在浊积事件重复频率较低的地方发展得最好,这意味着浊积岩与沉积较慢的半陆相沉积物和/或轮廓流沉积物交错层理。详细研究揭示了不同浊积环境下独特的生痕化石群[79-82]。在海底扇环境中,通道轴的厚层砂岩以低强度和低多样性的 Ophiomorpha 和 Thalassinoides 生痕化石群为特征。穿孔强度和群落多样性沿通道边缘(Pychosiphon-Thalassinoides 生痕化石群)向泛滥平原-堤岸环境增加。在这些薄层砂-泥浊积岩中,多样的 Planolites-Chondrites 生痕化石群占主导地位。在坡地围裙环境中,以 Nereites 生痕化石群为典型,生物扰动通常更为强烈和多样。Ophiomorpha 亚生痕化石群(含 Diplocriterion 和 Scolicia)特征化中上坡浊积岩,而 Paleodictyon 亚生痕化石群则特征化远坡区。
Texture. Sedimentary textures of turbidites yield important information on the capacity and competence of the turbidity current, as well as on the distance of transport and likely provenance. Mean grain size ranges from gravel to sand to silt/clay sizes, for coarse, medium and fine-grained turbidites, with isolated clasts in excess of 1 m length in some examples. Sorting is equally variable, but generally better (i.e., moderate to well-sorted) for fine- and medium-grained turbidites. Normal grading is the most common feature observed, either through the whole bed or at the top/base only, although completed ungraded beds also occur. In coarse-grained turbidites there may be a basal zone of reverse-grading overlain by a normally graded or ungraded bed. In fine-grained turbidites, graded silt-laminated units are typical in which the alternation of silt and mud laminae is the result of shear sorting through the basal boundary layer of the flow during deposition [52].
质地。浊积岩的沉积质地提供了关于浊流的运载能力和能量,以及运输距离和可能的来源地的重要信息。平均粒径范围从砾石到砂,再到粉砂/粘土尺寸,分别对应粗、中、细粒浊积岩,在某些实例中还可见超过 1 米长的孤立砾块。分选同样变化多样,但细粒和中粒浊积岩的分选通常较好(即中等至良好分选)。正常分级是最常见的特征,可能贯穿整个岩层,或仅出现在顶部或底部,尽管也存在完全无分级的岩层。在粗粒浊积岩中,底部可能存在逆分级带,覆盖于其上的则是正常分级或无分级的岩层。在细粒浊积岩中,典型的是分级的粉砂层理单元,其中粉砂和泥质层理的交替是由于沉积过程中流体底部边界层的剪切分选所致[52]。
Grain-size breaks. Abrupt changes in grain size across an intra-bed surface are a common feature of turbidites everywhere [83,84]. Five types were recognised in [85] between coarse and fine sand, medium and fine sand and between sand and mud. We would add two further marked breaks, namely, between gravel and sand and between silt and mud.
粒度断层。层内面上粒度的突然变化是浊积岩的普遍特征[83,84]。文献[85]中识别了五种类型,分别发生在粗细砂之间、中细砂之间以及砂和泥之间。我们还将补充两种明显的断层,即砾石与砂之间以及粉砂与泥之间。
Fabric. Turbidites commonly show well-developed long-axis grain or clast alignment parallel to the flow direction. Grain and clast imbrication shows up-flow inclination. Strong flow-parallel and bed parallel clay and silt alignment is typical of mud turbidites.
构造。浊积岩通常表现出沿流向排列良好的长轴颗粒或砾石排列。颗粒和砾石的重叠排列显示出上游倾斜。泥质浊积岩典型地具有强烈的与流向和平行于层面的粘土和粉砂排列。
Composition. Turbidites are most commonly siliciclastic, bioclastic, volcaniclastic or of mixed composition. More rarely, they are composed of chemiclastic material, i.e., reworked evaporites. They are characterised by (a) allochthonous elements introduced into an area so that the turbidite
组成。浊积岩最常见的是硅质碎屑岩、生物碎屑岩、火山碎屑岩或混合成分。较少见的是由化学碎屑物质组成,即再沉积的蒸发岩。其特征是(a)外来成分被引入某一地区,使得浊积岩

composition may differ markedly from that of in situ interbedded facies and (b) material derived from a shallow water and/or continental provenance.
组成可能与原位夹层相的组成显著不同,且(b)材料来源于浅水和/或大陆源区。

3.3. Turbidite Facies Models
3.3. 浊积岩相模型

These composite characteristics from multiple datasets have been synthesised into facies models for coarse-grained turbidites [25,34,78,86], medium-grained turbidites [12,87], and fine-grained turbidites [21,88,89]. For convenience, these are referred to as the Lowe, Bouma, and Stow sequences or facies models, after the authors who first established each respective scheme. Each of these facies models shows a characteristic sequence of sedimentary structures and grading which reflects deposition from a single turbidity current event (Figures 6-11). They are event deposits. The different structures are referred to as divisions within the sequence. The Stow sequence (T0-T8) (Figure 10) is more or less equivalent to the D-E divisions of the Bouma sequence (A-E) (Figure 8), or the E1-3 divisions of [88].
这些来自多个数据集的综合特征已被整合为粗粒浊积岩[25,34,78,86]、中粒浊积岩[12,87]和细粒浊积岩[21,88,89]的岩相模型。为了方便起见,这些模型分别被称为 Lowe、Bouma 和 Stow 序列或岩相模型,均以最早建立各自方案的作者命名。每个岩相模型都显示了沉积结构和分级的特征序列,反映了单次浊流事件的沉积(图 6-11)。它们是事件沉积物。不同的结构被称为序列中的分段。Stow 序列(T0-T8)(图 10)大致相当于 Bouma 序列(A-E)(图 8)中的 D-E 分段,或[88]中的 E1-3 分段。

Figure 8. The medium-grained turbidite family for sand and sand-mud turbidites. The ideal Bouma facies model showing the complete sequence of divisions A-E [12], and typical partial sequences found commonly in nature, is given. F is now commonly used for pelagites above a turbidite
图 8. 中粒浊积岩系列,适用于砂质和砂-泥质浊积岩。理想的 Bouma 岩相模型展示了完整的 A-E 分段序列[12],以及自然界中常见的典型部分序列。F 现在通常用于表示浊积岩上方的远洋沉积物。
Complete sequences are generally present in < 10 % < 10 % < 10%<10 \% of observed turbidites. More common are partial sequences in which the same order of divisions is preserved but not all are present in any one bed. For each sequence, the lower divisions represent deposition from the current when it is more energetic and the upper divisions when it is less energetic. For a single turbidity current, this can be achieved from more proximal to more distal, respectively, and also from channel axis to overbank. The same high to low energy regime applies to Lowe, Bouma and Stow turbidites. In some cases, Lowe divisions are overlain by Bouma divisions in a single bed or Bouma divisions by Stow divisions. Rarely, all three can occur in megaturbidites.
完整的沉积序列通常出现在观察到的浊积岩中约 < 10 % < 10 % < 10%<10 \% 的比例。更常见的是部分序列,其中各个分层的顺序保持不变,但在同一层中并非全部存在。对于每个序列,下部分层代表浊流能量较高时的沉积,上部分层则代表能量较低时的沉积。对于单一浊流,这种变化可以分别从近源区到远源区实现,也可以从河道轴线到河道外滩实现。相同的高能到低能环境适用于 Lowe、Bouma 和 Stow 浊积岩。在某些情况下,单层中 Lowe 分层上覆 Bouma 分层,或 Bouma 分层上覆 Stow 分层。极少数情况下,三者都可出现在巨型浊积岩中。
Fine-grained and medium-grained turbidites are best characterised by the Stow and Bouma models. These are shown, together with a typical range of partial sequences, in Figures 8-11. Modern and ancient examples of both types are shown in Figures 9 and 12. They represent deposition from uniform turbidity currents in the depletive regime of the Kneller matrix [90]. They are the most abundant and widespread types of turbidite in both marine and lacustrine settings. Coarse-grained turbidites are best characterised by the Lowe model (R1-S3) (Figure 6). All three models include distinct grain-size breaks, although these are not generally indicated on standard figures. For the Stow sequence, the most marked break is between the T0 and T1 divisions; for the Bouma sequence, between
细粒和中粒浊积岩最好用 Stow 和 Bouma 模型来描述。这些模型及其典型的部分序列范围见图 8-11。现代和古代这两种类型的实例见图 9 和 12。它们代表了 Kneller 矩阵[90]中耗散区均匀浊流的沉积。它们是海洋和湖泊环境中最丰富且分布最广的浊积岩类型。粗粒浊积岩则最好用 Lowe 模型(R1-S3)(图 6)来描述。所有三种模型都包含明显的粒度断层,尽管这些断层通常未在标准图中标出。对于 Stow 序列,最显著的断层位于 T0 和 T1 层之间;对于 Bouma 序列,位于部分序列中的砂和泥之间(AE 和 CE 层);对于 Lowe 序列,位于砾石和砂层之间(R3-S1)。

sand and mud in partial sequences (AE and CE divisions); and for the Lowe sequence, between gravel and sand divisions (R3-S1).
砂和泥在部分序列中(AE 和 CE 层);以及 Lowe 序列中砾石和砂层之间(R3-S1)。

Figure 9. Cont.  图 9。续。
Figure 9. Medium-grained turbidite family: photographic examples. (A) Sandstone turbidite succession (thin-, medium- and thick-bedded) interbedded with fine-grained turbidites (mud-rich), Annot Basin, SE France. (B) Sandstone-mudstone turbidite succession, thin- and medium-bedded, Zumaia Formation, N Spain. Scale stick 1.5 m . © Sandstone-mudstone turbidite succession, thin-bedded, Aberystwyth Grit Formation, Wales. (D) Sandstone-mudstone turbidite succession, thin- and medium-bedded, Apennines, Italy. (E) Example from Aberystwyth Grit Formation, Wales, showing Bouma sequence A-E turbidite. (F) Example from Misaki Formation, Japan, showing Bouma sequence A-E turbidite. (G) Example from Mzia Field, offshore Tanzania, showing sandy turbidites interbedded with fine-grained mud-silt turbidites. Core width 10 cm , scale bar in inches. (H) Example from North Brae Field, UK North Sea, showing sandy turbidites interbedded with fine-grained mud-silt turbidites. Core width 10 cm .
图 9. 中粒度浊积岩系列:照片示例。(A) 砂岩浊积岩层序(薄层、中层和厚层)与细粒浊积岩(富泥)交错层理,Annot 盆地,法国东南部。(B) 砂岩-泥岩浊积岩层序,薄层和中层,Zumaia 组,西班牙北部。比例尺 1.5 米。© 砂岩-泥岩浊积岩层序,薄层,Aberystwyth 砂岩组,威尔士。(D) 砂岩-泥岩浊积岩层序,薄层和中层,亚平宁山脉,意大利。(E) 来自 Aberystwyth 砂岩组的示例,显示 Bouma 序列 A-E 浊积岩。(F) 来自日本 Misaki 组的示例,显示 Bouma 序列 A-E 浊积岩。(G) 来自坦桑尼亚近海 Mzia 油田的示例,显示砂质浊积岩与细粒泥-粉砂浊积岩交错层理。岩心宽度 10 厘米,比例尺以英寸为单位。(H) 来自英国北海 North Brae 油田的示例,显示砂质浊积岩与细粒泥-粉砂浊积岩交错层理。岩心宽度 10 厘米。

Figure 10. The fine-grained turbidite family for silt and mud turbidites. The ideal Stow facies model showing the complete sequence of divisions T0-T8 [21,89], and typical partial sequences found commonly in nature, is given.
图 10. 细粒浊积物家族,适用于粉砂和泥质浊积物。理想的 Stow 相模型展示了完整的 T0-T8 分层序列[21,89],以及自然界中常见的典型部分序列。

Figure 11. Alternative fine-grained turbidite facies models.
图 11. 替代的细粒浊积物相模型。

Variations from the Standard Models
标准模型的变异

There are several variations from the standard facies models described above, in addition to the widespread occurrence of partial sequences. These variations may arise due to (a) flow transformations during a single downslope event, between debris flows and within high to low concentration turbidity currents, (b) the actual process and rate of deposition through the traction carpet or boundary layer and © the well-documented process-facies continuum of turbidity currents and turbidites, as outlined above.
除了广泛存在的部分序列外,上述标准相模型还存在若干变异。这些变异可能源于:(a) 单次下坡事件中流动的转变,包括碎屑流之间以及高浓度到低浓度浊流内的变化,(b) 通过牵引地毯或边界层的实际沉积过程和速率,以及 (c) 如上所述,浊流和浊积物的过程-相连续体的充分证实过程。
In terms of composition, the Lowe, Bouma and Stow models were developed from siliciclastic systems but have been shown to apply equally to bioclastic and volcaniclastic turbidites [91-93]. Some differences have been documented for calcareous bioclastic turbidites. For example, calcarenite turbidites may display a large-scale dune cross-bedded division, which is typically missing from siliciclastic turbidites. Calcilutite turbidites show a less distinct silt laminated division than siliciclastics, and a more gradual, often reverse-graded, upward transition into hemipelagic or pelagic ooze [55,91]. Too few examples of chemiclastic turbidites have been described to establish what differences they may display [94].
在成分方面,Lowe、Bouma 和 Stow 模型最初是从硅质碎屑系统中发展而来,但已被证明同样适用于生物碎屑和火山碎屑浊积岩[91-93]。对于含钙生物碎屑浊积岩,已有一些差异被记录。例如,钙砂岩浊积岩可能表现出大尺度的沙丘交错层理,这在硅质碎屑浊积岩中通常缺失。钙泥岩浊积岩显示出比硅质碎屑岩更不明显的粉砂层理分层,以及向上逐渐过渡到半深海或深海软泥的过程,这种过渡通常是逆级配的[55,91]。关于化学碎屑浊积岩的描述实例太少,尚无法确定其可能表现出的差异[94]。
In distal turbidite environments and channel levee-overbank settings, silt beds ( > 70 % > 70 % > 70%>70 \% silt-sized particles) are more abundant than sands and commonly occur as thin or medium-bedded turbidites. These silt beds exhibit the same suite of structures (the Bouma sequence) as sand-mud turbidites. Ungraded structureless silts are found more proximally and can be attributed to AE-division Bouma turbidites. Strachan et al., 2016 [36] describes other variations of silt and silty-sand turbidites with a wide ranging of grading styles, including ungraded, reverse and normal-graded silt turbidites from proximal settings (Figure 8).
在远端浊积岩环境和河道堤岸泛滥平原环境中,粉砂层( > 70 % > 70 % > 70%>70 \% 粒径为粉砂级的颗粒)比砂层更为丰富,通常以薄层或中层浊积岩形式出现。这些粉砂层表现出与砂-泥浊积岩相同的一系列结构(Bouma 序列)。无分级的无结构粉砂更多见于近端区域,可归因于 AE 段 Bouma 浊积岩。Strachan 等人(2016)[36] 描述了粉砂和粉砂-砂浊积岩的其他变体,具有多种分级样式,包括来自近端环境的无分级、逆分级和正分级粉砂浊积岩(见图 8)。

Figure 12. Fine-grained turbidite family, variously interbedded with other turbidite and related facies: photographic examples. (A) Very-thin-bedded turbidites (sand/silt to mud ) with partial Stow sequences. Note distinctive faded-ripple basal divisions (Stow T0), long-wavelength low-amplitude ripples (lenticular lamination, Stow T2) and parallel silt-mud lamination (Stow T3). (B) Very-thin-bedded turbidites (silt to mud) with partial Stow sequences (as above). Note also that the lower bed is a disorganised fine-grained turbidite. © Very-thin-bedded turbidites (silt to mud) with partial Stow sequences (as above), including upper muddy divisions (Stow T4-6). (D)-Thin-bedded and very-thin-bedded turbidite succession (sand, silt and mud), Aberystwyth Grits, Wales. Width of view is 0.75 m .
图 12. 细粒浊积岩系列,与其他浊积岩及相关相互交错:照片示例。(A) 极薄层浊积岩(砂/粉砂至泥质),含部分 Stow 序列。注意独特的褪色波纹基底分层(Stow T0)、长波长低振幅波纹(透镜状层理,Stow T2)和平行粉砂-泥质层理(Stow T3)。(B) 极薄层浊积岩(粉砂至泥质),含部分 Stow 序列(同上)。还注意下层为无序细粒浊积岩。(C) 极薄层浊积岩(粉砂至泥质),含部分 Stow 序列(同上),包括上部泥质分层(Stow T4-6)。(D) 薄层及极薄层浊积岩连续体(砂、粉砂和泥质),威尔士阿伯里斯特威斯砂岩。视野宽度为 0.75 米。
Medium- to very-thick-bedded mud turbidites are known from a variety of environments, including ponded basins [72,95-97], channel-fill successions [17], open slope and base-of slope settings [70] and distal fan lobes [98]). Thick mud turbidites may appear completely structureless or homogeneous and are also known as homogenites or unifites. In distal and basin plain settings they may be associated with hemiturbidites, the result of very slow deposition from the suspension cloud that develops above and beyond the feather edge of true turbidite deposition [32,33]. Hemiturbidites have the same composition as the associated mud turbidites but are structureless, ungraded and very fine-grained, and are bioturbated throughout. Very-thick-bedded and structureless sand turbidites are also common in certain settings (e.g., channel-fill and confined basins). These beds are part of the deep-water massive sand facies association [99].
中厚至极厚层理的泥质浊积岩已知存在于多种环境中,包括积水盆地[72,95-97]、河道充填层序[17]、开阔坡面及坡脚环境[70]以及远端扇叶[98]。厚层泥质浊积岩可能表现为完全无结构或均质状态,也称为均质岩或单一岩。在远端和盆地平原环境中,它们可能与半浊积岩相关联,后者是由悬浮云在真正浊积岩沉积羽毛边缘之上及之外非常缓慢沉积形成的[32,33]。半浊积岩与相关泥质浊积岩成分相同,但无结构、无分级且粒度极细,并且贯穿生物扰动。在某些环境(如河道充填和受限盆地)中,极厚层理且无结构的砂质浊积岩也很常见。这些岩层属于深水巨厚砂岩相组合的一部分[99]。
There is a group of thin-, medium- and thick-bedded turbidites that do not show clear Stow or Bouma sequences, have absent or very indistinct lamination and do not have a clear separation between their sand/silt and mud fractions [26,55]. Some show distinctive normal grading whereas others have poor grading and abundant small mudstone clasts. We interpret these as the deposits of immature, surge-type turbidity currents. They may have developed from cohesive debris flows.
有一组薄层、中层和厚层的浊积岩,它们没有明显的 Stow 或 Bouma 序列,层理缺失或非常不明显,且其砂/粉砂和泥质部分之间没有明显分界[26,55]。有些显示出明显的正常分级,而另一些则分级较差,含有大量小泥岩砾块。我们将这些解释为未成熟的、冲击型浊流的沉积物。它们可能由胶结性碎屑流发展而来。

4. Contourite Deposits  4. 轮廓流沉积物

4.1. Definition and Facies
4.1. 定义与相

Contourites are defined as all those sediments deposited or substantially reworked by the persistent action of bottom currents [ 28 , 57 , 100 , 101 ] [ 28 , 57 , 100 , 101 ] [28,57,100,101][28,57,100,101]. The term ‘contourite’ was originally used specifically for sediments deposited in the deep sea by contour-parallel (alongslope) bottom currents driven by thermohaline circulation. It has since been widened to embrace a range of sediments affected by
轮廓流沉积物被定义为所有由底层洋流持续作用沉积或大幅重塑的沉积物 [ 28 , 57 , 100 , 101 ] [ 28 , 57 , 100 , 101 ] [28,57,100,101][28,57,100,101] 。“轮廓流”一词最初专指由热盐环流驱动的沿等深线(沿坡)底层洋流在深海沉积的沉积物。此后,该术语的范围已扩大,涵盖了受多种沉积物影响的情况

different types of current, including those that act in shallower water [101]-i.e., upper slope and outer shelf depths-as well as in large lakes and inland seas. These are referred to as shallow-water and lacustrine contourites, respectively.
不同类型的洋流,包括作用于较浅水域的洋流[101]——即上陆坡和外陆架深度——以及大型湖泊和内陆海洋中的洋流。这些分别被称为浅水和湖泊轮廓沉积物。
A wide range of different contourite facies are now recognised, as illustrated in Figure 13. These range in grain size from fine muds, through silts and sands, to sand and gravel lag deposits, and are often poorly sorted mixtures of different grain size fractions. In composition they are equally varied, including siliciclastic, bioclastic (calcareous and siliceous), volcaniclastic, and chemogenic (manganiferous) varieties, commonly displaying a mixed composition.
目前已识别出多种不同的轮廓沉积相,如图 13 所示。这些沉积物的粒度范围从细泥、粉砂和砂,到砂砾滞留沉积物,通常是不同粒径组分的混合且分选较差。在成分上也同样多样,包括硅质碎屑、生物碎屑(含钙质和硅质)、火山碎屑和化学成因(含锰)类型,常表现为混合成分。

BI-GRADATIONAL CONTOURITE FACIES: Fine grained mud-sand contourites
双渐变轮廓沉积相:细粒泥-砂轮廓沉积物

Figure 13. The bi-gradational contourite family for fine-grained mud-sand contourites. The ideal bi-gradational facies model showing the complete sequence of divisions C1-C5 [28,102] and typical partial sequences found commonly in nature is given.
图 13. 细粒泥-砂轮廓沉积物的双渐变轮廓沉积物系列。理想的双渐变沉积相模型展示了完整的 C1-C5 分区序列[28,102]及自然中常见的典型部分序列。
Siliciclastic contourites are well known from a wide range of marine settings, including continental slopes, abyssal plains and shallow-marine and high-latitude settings, and are most easily recognised as part of large-scale contourite drift deposits. They commonly occur as thick featureless units which are poorly bedded, with a more or less cyclic alternation of muddy, silty and sandy facies, characterised as bi-gradational sequences (Figure 13). In any one location they tend to show a very uniform, monotonous aspect in terms of colour, texture and composition. They are generally highly bioturbated, often with an indistinct mottled appearance, and may further show distinct burrows of varied (deep-water) ichnofacies [103,104]. There may be rare primary lamination present (partly destroyed by bioturbation), diffuse and indistinct, in places marked by colour change and in places by irregular winnowed concentrations of coarser material.
硅质碎屑质轮廓沉积物在多种海洋环境中广为人知,包括大陆坡、深海平原以及浅海和高纬度环境,最容易被识别为大规模轮廓沉积漂积物的一部分。它们通常以厚实且无明显特征的单元出现,层理较差,呈现泥质、粉砂质和砂质相的或多或少循环交替,特征为双渐变序列(图 13)。在任何一个地点,它们在颜色、质地和成分方面往往表现出非常均一、单调的特征。它们通常生物扰动严重,常呈现不明显的斑驳外观,并可能进一步显示出各种(深水)生痕相的明显生痕孔[103,104]。可能存在罕见的原生层理(部分被生物扰动破坏),呈弥散且不明显的状态,有些地方以颜色变化标记,有些地方则以不规则的淘洗粗颗粒集中体现。
Sandy contourites (Figure 14) are known to make up thin to thick ( 5 500 m 5 500 m 5-500m5-500 \mathrm{~m} thick) sheeted drifts, covering extensive areas of the seafloor over the outer shelf/upper slope, across slope terraces and in oceanic gateways and flooring contourite channels. In such areas, the seafloor is typically ornamented by a range of current-induced bedforms (ripples, dunes and furrows) and the underlying sediment may preserve internal sedimentary structures such as cross-lamination, large-scale cross-bedding and parallel lamination. Structureless and bioturbated sands are also common.
砂质轮廓沉积物(图 14)已知可形成薄至厚( 5 500 m 5 500 m 5-500m5-500 \mathrm{~m} 厚)的层状漂积,覆盖外陆架/上坡、坡地阶地以及海洋通道和轮廓沉积通道的广泛海底区域。在这些区域,海底通常布满各种由洋流引起的床面形态(波纹、沙丘和沟槽),底层沉积物可能保存有内部沉积结构,如交错层理、大尺度交错层理和平行层理。无结构和生物扰动的砂层也很常见。
SANDY CONTOURITE MODELS: Muddy-sands, fine-medium sands, medium-coarse sands
砂质轮廓沉积模型:泥质砂、细-中砂、中-粗砂

Figure 14. The sandy contourite family for muddy sands, fine-to-medium sands and medium-to-coarse sands. After [105].
图 14. 泥质砂、细至中砂和中至粗砂的砂质轮廓沉积物系列。资料来源:[105]。
Calcareous bioclastic contourites are prevalent wherever the dominant supply to the bottom-current and drift systems is made up of carbonate material. This may be from erosion and downslope reworking of carbonate banks and bioherms, or from pelagic fall-out, especially in regions underlying high primary productivity. Apart from compositional differences, their characteristics are otherwise similar to those of siliciclastic contourites. These calcicontourites are well known from ancient contourite successions exposed on land, which are described in a subsequent section.
含钙生物碎屑轮廓沉积物广泛分布于底流和漂积系统的主要供应物质为碳酸盐材料的区域。这些材料可能来自碳酸盐礁台和生物礁的侵蚀及坡下重工作用,或来自远洋沉降,尤其是在高初级生产力区域的底部。除成分差异外,其特征与硅质轮廓沉积物相似。这些钙质轮廓沉积物在陆地上暴露的古老轮廓沉积层中有较好记录,后续章节将对此进行描述。
We show the principal facies models for contourites in Figures 13 and 14. The deposit characteristics, as described below, are illustrated with photographs in Figures 15 and 16. As for turbidites (above), these are based on a long and extensive history of contourite study and publications, as synthesised in [1,3,15,17,28,77,106-109], amongst others.
我们在图 13 和图 14 中展示了轮廓沉积物的主要相模型。下文描述的沉积特征通过图 15 和图 16 中的照片加以说明。与上述浊积物类似,这些模型基于长期且广泛的轮廓沉积研究和出版物的综合总结,[1,3,15,17,28,77,106-109]等文献中均有体现。

Figure 15. Cont.  图 15. 续。
Figure 15. Contourite family: photographic examples of modern contourites, core sections. Locality: ( A H ) ( A H ) (A-H)(\mathbf{A}-\mathbf{H}) and ( J M ) ( J M ) (J-M)(\mathbf{J}-\mathbf{M}) are from the Gulf of Cadiz, N Atlantic while ( I , N ) ( I , N ) (I,N)(\mathbf{I}, \mathbf{N}) are from the Hebridean margin, NE Atlantic. (A-G) from [105]. (A) Muddy contourite, bioturbated. (B) Silty mud contourite, bioturbated and with thin silt lenses. © Muddy silt contourite, bioturbated and with thin silt lenses. (D) Muddy sand contourite, bioturbated and with irregular lenses. (E) Muddy fine sand contourite, with parallel lamination. (F) Muddy fine sand contourite, structureless. (G) Medium to coarse-grained sand collected as grab sample from seafloor contourite. (H) Part of bi-gradational contourite sequence (divisions as shown). (I) Muddy and silty contourites. (J) Core sections from contourite depositional system drilled during the Integrated Ocean Drilling Program (IODP) Expedition 339, showing muddy and silty contourites with indistinct lamination, and complete bi-gradational contourite sequence (right). (K-L) Sandy contourites, with parallel and cross-bedding. (M) Sandy contourite, structureless and muddy, Campos slope, offshore Brazil. (N) Pebbly sand contourite, Barra contourite sand sheet.
图 15. 轮廓流沉积物家族:现代轮廓流沉积物的照片示例,岩心剖面。地点: ( A H ) ( A H ) (A-H)(\mathbf{A}-\mathbf{H}) ( J M ) ( J M ) (J-M)(\mathbf{J}-\mathbf{M}) 来自大西洋北部的加的斯湾, ( I , N ) ( I , N ) (I,N)(\mathbf{I}, \mathbf{N}) 来自大西洋东北部的赫布里底海岸边缘。(A-G) 来源于[105]。(A) 泥质轮廓流沉积物,生物扰动。(B) 粉砂质泥轮廓流沉积物,生物扰动,带有薄的粉砂透镜。(C) 泥质粉砂轮廓流沉积物,生物扰动,带有薄的粉砂透镜。(D) 泥质砂轮廓流沉积物,生物扰动,带有不规则透镜。(E) 泥质细砂轮廓流沉积物,具有平行层理。(F) 泥质细砂轮廓流沉积物,无结构。(G) 从海底轮廓流采集的中到粗粒砂抓取样品。(H) 部分双向渐变轮廓流序列(划分如图所示)。(I) 泥质和粉砂质轮廓流沉积物。(J) 综合海洋钻探计划(IODP)第 339 次远征钻探的轮廓流沉积系统岩心剖面,显示泥质和粉砂质轮廓流沉积物,层理不明显,以及完整的双向渐变轮廓流序列(右侧)。(K-L) 砂质轮廓流沉积物,具有平行层理和交错层理。(M) 砂质轮廓流沉积物,无结构且泥质,巴西近海坎波斯坡。(N) 卵砾砂轮廓流沉积物,巴拉轮廓流砂层。

Figure 16. Cont.  图 16. 续。
Figure 16. Contourite family: photographic examples of ancient contourites. (A) Miocene siliciclastic contourite succession, Rifean Gateway, Morocco. The view shows large-scale alternation of more mud-rich (grey) and more sand-rich (brown) contourites, as well as small-scale contourite cyclicity. (B) Detail from (a) above of sandy contourite, poorly sorted and structureless. © Detail from (a) above of muddy/silty contourite, poorly sorted and structureless. Note that surface mud wash has been partly scraped away to show a mud (grey) to silt (brown) sequence. (D,E) Sandy contourite succession, siliciclastic, Rifean Gateway, Morocco. The view shows large-scale cross-stratification and parallel stratification. It is interpreted as deep tidal bottom currents enhancing flow speed of thermohaline bottom currents. (F) Oligo-Miocene carbonate contourite succession, Petra tou Romiou, southern Cyprus. A pencil lying along typical lenticular calcarenite contourite facies is shown. (G) Oligo-Miocene carbonate contourite succession, Petra tou Romiou, southern Cyprus. Bi-gradational sequence from calcilutite/calcisiltite near base (hammer handle, sampling numbers 3-4) to lenticular calcarenite (numbers 6-9) to calcilutite/calcisiltite (sampling number 10). (H) Detail of lenticular calcarenite contourites.
图 16. 轮廓流沉积物家族:古代轮廓流沉积物的照片实例。(A) 摩洛哥里费安通道中新世硅质碎屑轮廓流沉积序列。视图显示了更多泥质(灰色)和更多砂质(棕色)轮廓流沉积物的大尺度交替,以及小尺度的轮廓流周期性。(B) 上图(a)中砂质轮廓流沉积物的细节,分选差且无结构。© 上图(a)中泥质/粉砂质轮廓流沉积物的细节,分选差且无结构。注意表面泥质冲刷部分被刮去,显示出泥(灰色)到粉砂(棕色)的序列。(D,E) 摩洛哥里费安通道硅质碎屑砂质轮廓流沉积序列。视图显示大尺度的交错层理和平行层理。解释为深层潮汐底流增强了热盐底流的流速。(F) 塞浦路斯南部 Petra tou Romiou 的渐新世-中新世碳酸盐轮廓流沉积序列。图中放置了一支铅笔,沿着典型的透镜状砂灰岩轮廓流相。(G) 塞浦路斯南部 Petra tou Romiou 的渐新世-中新世碳酸盐轮廓流沉积序列。 从基底附近的钙泥岩/钙粉砂岩(锤柄,采样编号 3-4)到透镜状钙砂岩(编号 6-9)再到钙泥岩/钙粉砂岩(采样编号 10)的双渐变序列。(H)透镜状钙砂岩轮廓沉积物的细节。

4.2. Contourite Characteristics
4.2. 轮廓沉积物特征

Bedding. Contourite bedding is poorly developed or indistinct in thick muddy successions developed under low-energy bottom-current systems but becomes more evident with an increased silt
层理。轮廓沉积物的层理在厚厚的泥质沉积物中发育较差或不明显,这些沉积物形成于低能量底流系统下,但随着由高能流体输送的粉砂和砂成分的增加,层理变得更加明显。

and sand component delivered by higher-energy currents. The sand supply is influenced by long-term ( 5000 20 , 000 y 5000 20 , 000 y 5000-20,000y5000-20,000 \mathrm{y} ) fluctuations in mean bottom-current velocity, as well as by variation in sediment supply, either turbidite or pelagic influx. Sand-rich contourite successions are generally well-bedded due to common mud-rich interbeds.
砂的供应受长期( 5000 20 , 000 y 5000 20 , 000 y 5000-20,000y5000-20,000 \mathrm{y} )平均底流速度波动的影响,同时也受沉积物供应变化的影响,无论是浊积物还是远洋沉积物输入。富砂的轮廓沉积物层序通常层理发育良好,因为常见的泥质夹层存在。
Structures. Contourites recovered from mud-rich drift systems are characterised by a notable absence of clear, distinct lamination and by the presence of common to abundant pervasive bioturbation. In some cases they appear completely homogeneous, whereas in other cases they show indistinct and discontinuous parallel lamination, partial grain alignment, sub-horizontal to irregular erosion surfaces, thin layers and lenses of coarser material. Cross-lamination is only rarely present in silts and fine sands.
结构。来自富含泥质的漂积系统的轮廓沉积物的特征是明显缺乏清晰、明显的层理,并且普遍存在常见到丰富的生物扰动。在某些情况下,它们看起来完全均质,而在其他情况下,则表现为模糊且不连续的平行层理、部分颗粒排列、亚水平至不规则的侵蚀面、薄层和较粗物质的透镜体。交错层理仅偶尔出现在粉砂和细砂中。
The paucity of cross-lamination is somewhat surprising as the present-day seafloor beneath bottom currents is commonly covered with ripples, dunes, lineation and other current-induced bedforms. However, the presence of pervasive bioturbation rather than lamination might be explained by relatively low rates of semi-continuous contourite accumulation, meaning bioturbation is able to keep pace with deposition and effectively destroy most primary lamination. For muddy contourites, the low current velocities and sediment concentrations are insufficient to result in any clear primary lamination, although minor erosion/non-depositional surfaces and silty/sandy lens and layers are evidence of repeated and alternating phases of erosion, winnowing and deposition.
交错层理的稀少有些令人惊讶,因为现今海底在底流作用下通常覆盖着波纹、沙丘、线状结构及其他由水流引起的床面形态。然而,广泛存在的生物扰动而非层理的出现,可能是由于半连续的等深流沉积速率较低,意味着生物扰动能够跟上沉积速度,有效破坏大部分原始层理。对于泥质等深流来说,较低的流速和沉积物浓度不足以形成明显的原始层理,尽管轻微的侵蚀/非沉积面以及粉砂/砂质透镜和层理则表明了反复交替的侵蚀、筛选和沉积阶段。
Laminated and cross-laminated sandy contourites are known from beneath higher-velocity bottom currents with large-scale bedforms (e.g., dunes) evident on the sea-floor. The lamination is distinct, typically diffuse and widely-spaced, and may be associated with limited bioturbation. The presence of such structures clearly indicates bedload tractional movement of granular sediments by the bottom current. Preservation of the primary lamination is due to rapid sedimentation, high current velocity, and/or the dearth of organic matter. Ancient contourites with cross-lamination preserved have been documented from the Miocene in Morocco [110] and Oligocene in Cyprus [111].
层状和交错层状的砂质轮廓沉积物已知存在于较高流速的底流之下,海底可见大规模的床形(如沙丘)。这些层理清晰,通常呈弥散状且间距较大,可能伴有有限的生物扰动。这类结构的存在明确表明底流通过床载牵引运动搬运颗粒沉积物。原始层理的保存归因于快速沉积、高流速和/或有机物质的缺乏。保存有交错层理的古轮廓沉积物已在摩洛哥中新世[110]和塞浦路斯渐新世[111]得到记录。
Bioturbation. Pervasive bioturbation has long been recognised as a distinctive feature of contourites [28,100,103], with well-developed bioturbation common throughout the beds (rather than top-down as for turbidites (see above)). There is a clear link between ichnofacies assemblage and a combination of current strength and organic matter supply. Strong bottom currents deposit sand-rich contourites which are relatively poor in organic matter and which have common omission surfaces and hiatuses. Long-term omission yields indurated discontinuity surfaces marked by a stiffto hard-ground ichnofacies; where overlain by sand, a typical Glossifungites ichnofacies is present, and, where covered by mud, a sharp-walled piped zone results. The upper parts of sandy contourite layers contain biodeformational structures resulting from ploughers and passively ventilated tube systems. These burrows become overprinted by deeper penetrating ones like Skolithos, Scolicia and Planolites, in addition to the U-shaped Teichichnus deep-dwelling crustacean burrows such as Thalassinoides and Gyrolithes.
生物扰动。广泛的生物扰动长期以来被认为是轮廓沉积物的一个显著特征[28,100,103],且生物扰动在整个沉积层中普遍存在(而非像浊积岩那样自上而下分布(见上文))。生物迹化石组合与底流强度和有机质供应的组合之间存在明显联系。强底流沉积的砂质轮廓沉积物有机质相对较少,常见省略面和间断层。长期的省略形成硬化的不连续面,表现为坚硬地面生物迹化石群;当其上覆有砂层时,典型的 Glossifungites 生物迹化石群出现;当被泥层覆盖时,则形成锐壁的管状区。砂质轮廓沉积层的上部含有由犁形生物和被动通气管系统形成的生物变形结构。这些生物洞穴随后被更深层穿透的生物迹如 Skolithos、Scolicia 和 Planolites 覆盖,此外还有 U 形的 Teichichnus 以及深居甲壳类生物洞穴如 Thalassinoides 和 Gyrolithes。
Weak bottom currents deposit mud-rich contourites that are generally richer in organic matter. Within such organic-rich muds, oxygen consumption by benthic animals and bacteria may lead the anoxia of pore water at shallow burial depths. The ichnofauna is both small in size of individuals and low in diversity (including monospecific populations). Chondrites and Trichichnus are often dominant, together with Phycosiphon, Planolites and less specific ‘mycellia’ traces. Pyritisation is common. Where omission surfaces occur, vertical tubes and Glossifungites ichnofacies are evident.
弱底流沉积富含泥质的轮廓沉积物,通常有较高的有机质含量。在这些富含有机质的泥质中,底栖动物和细菌的耗氧作用可能导致浅埋深度孔隙水的缺氧。生痕动物群体个体体型较小且多样性低(包括单一物种群体)。软骨虫属(Chondrites)和三毛虫属(Trichichnus)常占主导地位,同时伴有藻管属(Phycosiphon)、平面虫属(Planolites)及较不特异的“菌丝状”痕迹。黄铁矿化现象普遍存在。在存在省略面的位置,可见垂直管道和 Glossifungites 生痕相。
Contourite bi-gradational sequences (see below) show a distinctive variation in ichnofacies linked to current strength through the sandy (larger and more diverse assemblage), silt-mottled and muddy sequence divisions (smaller and less diverse assemblage).
轮廓沉积双向渐变序列(见下文)显示出生痕相的显著变化,这与流速有关,贯穿砂质(个体较大且群落多样性较高)、粉砂斑驳和泥质序列部分(个体较小且群落多样性较低)。
Texture. The sedimentary texture of contourites provides important information on the nature of transport and deposition by bottom currents [63]. Mean grain size, and in particular, the sortable silt component, is a key indicator of flow speed [112,113]. Bivariate cross plots (e.g., mean size versus sorting) reveal the carrying capacity and degree of winnowing, as well as the input of external material to the bottom current [105]. Grain-size distribution spectra are more or less unimodal, and, on cumulative
质地。轮廓沉积物的沉积质地为底流的运输和沉积性质提供了重要信息[63]。平均粒径,尤其是可分选粉砂组分,是流速的关键指标[112,113]。双变量交叉图(例如,平均粒径与分选度)揭示了承载能力和筛选程度,以及外来物质对底流的输入[105]。粒径分布谱大多为单峰型,且在累积曲线上

frequency plots, commonly show a tripartite subdivision into a coarser-grained bedload fraction moved by traction, an intermediate fraction moved as saltation load, and a finer-grained fraction transported wholly in suspension. Still coarser-grained contourites (coarse sand and gravel-rich) are moved wholly and intermittently as bedload.
频率图通常显示出三分法划分:由牵引力搬运的较粗颗粒床载物分级、中间分级作为跳跃负载搬运,以及完全悬浮运输的较细颗粒分级。更粗颗粒的轮廓沉积物(富含粗砂和砾石)则完全且间歇性地作为床载物搬运。
The dominant grain size of mud-rich contourite drift deposits is clayey silt and silty clay ( 125 0.5 μ m 125 0.5 μ m 125-0.5 mum125-0.5 \mu \mathrm{~m} ). They commonly show poor sorting (1.4-2.5 phi) and may contain significant (up to 15 % 15 % 15%15 \% ) sand-size material ( > 63 μ m ) ( > 63 μ m ) ( > 63 mum)(>63 \mu \mathrm{~m}). The sand fraction is typically made up of biogenic tests (calcareous or siliceous) or ice-rafted material at high latitudes. Sandy contourites are mostly fine- to medium-grained and are more rarely coarse-grained or pebbly. In many cases, they are only moderately to poorly sorted ( 0.8 2 phi 0.8 2 phi 0.8-2phi0.8-2 \mathrm{phi} ), partly as a result of bioturbational mixing with mud grade material, whereas the laminated sands may be moderately well-sorted ( 0.5 0.7 phi 0.5 0.7 phi 0.5-0.7phi0.5-0.7 \mathrm{phi} ).
泥质轮廓流堆积物的主导粒径为粘土质粉砂和粉砂质粘土( 125 0.5 μ m 125 0.5 μ m 125-0.5 mum125-0.5 \mu \mathrm{~m} )。它们通常表现出较差的分选(1.4-2.5 phi),并且可能含有显著的(高达 15 % 15 % 15%15 \% )砂粒大小的物质 ( > 63 μ m ) ( > 63 μ m ) ( > 63 mum)(>63 \mu \mathrm{~m}) 。砂粒部分通常由生物成因的壳体(含钙质或硅质)或高纬度地区的冰漂物组成。砂质轮廓流大多为细至中粒,较少为粗粒或砾石。在许多情况下,它们的分选仅为中等至较差( 0.8 2 phi 0.8 2 phi 0.8-2phi0.8-2 \mathrm{phi} ),部分原因是与泥质物料的生物扰动混合,而层理砂则可能分选较好( 0.5 0.7 phi 0.5 0.7 phi 0.5-0.7phi0.5-0.7 \mathrm{phi} )。
Bi-gradational grading is the norm for most mud-sand contourite successions (see Contourite Facies Models below). Individual bi-gradational units are typically between 0.5 m to 3.0 m in thickness. They are less evident in finer-grained mud-dominated successions and are more truncated (or absent) in sand-rich successions.
双向渐变分选是大多数泥砂轮廓流层序的常态(见下文轮廓流相模型)。单个双向渐变单元的厚度通常在 0.5 米至 3.0 米之间。在细粒泥质主导的层序中,这种特征不太明显,而在富砂层序中则更为截断(或缺失)。
Fabric. The sedimentary fabric or microfabric of contourites is still poorly known, and some conflicting results have been published. There is some evidence that grain alignment of silts and fine magnetic particles (using anisotropy of magnetic susceptibility measurements) shows flow-parallel trends. However, other data indicate a more chaotic grain orientation. A recent detailed study using scanning electron microscopy with automated image analysis has revealed that both silt and clay microfabrics show a combination of preferred bed-parallel alignment, semi-random/preferred and wholly random grain orientation. This is interpreted as the result of flow shear during deposition creating a weak to strong fabric, depending on current strength, and pervasive bioturbation tending to disrupt that fabric [114].
结构。轮廓沉积物的沉积结构或微结构仍然知之甚少,且已有一些相互矛盾的研究结果。部分证据表明,粉砂和细磁性颗粒的颗粒排列(通过磁化率各向异性测量)呈现与流向平行的趋势。然而,其他数据则显示颗粒取向较为混乱。最近一项利用扫描电子显微镜结合自动图像分析的详细研究发现,粉砂和粘土的微结构均表现出床面平行优选排列、半随机/优选以及完全随机的颗粒取向组合。这被解释为沉积过程中流动剪切作用形成的弱到强结构,具体取决于流速强度,而广泛的生物扰动则倾向于破坏该结构[114]。
Composition. Contourites vary in composition from one region to another, as evidenced by the different facies types, e.g., siliciclastic, calcareous, volcaniclastic, and others (see above). Quite commonly, they display a mixed terrigenous-biogenic composition which can be quite uniform throughout any one contourite depositional system. This uniform admixture of components indicates a range of sources and supply routes, as well as depositional mixing of components, which has been persistent across time. These include (a) the vertical settling of pelagic material from the surface, (b) slow horizontal advection and suspension cascading of hemipelagic material, © downslope input from turbidity currents and hyperpycnal plumes, (d) downslope flux via spillover processes and (e) alongslope supply via the bottom current from material that has been eroded, winnowed and re-suspended from the seafloor upstream from or adjacent to the site of deposition.
组成。等深流沉积物的组成因地区而异,如不同的相类型所示,例如硅质碎屑、含钙质、火山碎屑等(见上文)。它们通常表现出陆源-生物混合的组成,在任何一个等深流沉积系统中都可能相当均匀。这种成分的均匀混合表明存在多种来源和供应路径,以及成分的沉积混合,这种情况在时间上持续存在。这些包括:(a) 表层浮游物质的垂直沉降,(b) 半远洋沉积物的缓慢水平平流和悬浮级联,(c) 由浊流和超密流羽流带来的下坡输入,(d) 通过溢流过程的下坡通量,以及(e) 由底流沿坡供应的物质,这些物质来自沉积地点上游或邻近海底被侵蚀、筛选和再悬浮的材料。
Certain processes and hence component inputs will dominate in different contourite settings. In most cases, the sand-sized fraction will show partial fragmentation, rounding and iron-staining, which is all indicative of bottom-current transport as saltation load and bedload.
在不同的等深流沉积环境中,某些过程及其组成成分的输入将占主导地位。在大多数情况下,砂粒级部分会表现出碎裂、圆磨和铁锈染色,这些特征均表明底流以跳跃负荷和床载方式运输沉积物。

4.3. Contourite Facies Models
4.3. 等深流沉积相模型

Separate facies models for muddy and sandy contourites were originally proposed in the late 1970s [100,115]. Subsequent work demonstrated that these muddy and sandy facies, together with intervening silty contourites, commonly occur in composite sequences or partial sequences a few decimetres in thickness (typical range 0.5 3 m 0.5 3 m 0.5-3m0.5-3 \mathrm{~m} ). The now standard bi-gradational facies model shows overall negative grading (coarsening-up) from muddy through silt-mottled to sandy contourites and then positive grading (fining-up) back through silt-mottled to muddy contourite facies [116]. Well-defined sedimentary structures are generally absent, in part because they have been thoroughly destroyed by bioturbation. There may be an indistinct and discontinuous parallel lamination and lenses of coarser material. Primary structures, including rare cross-lamination, are more evident in coarse silts and sands than in finer-grained facies. This model applies to all compositional types.
泥质和砂质等深流相的独立相模型最早于 20 世纪 70 年代末提出[100,115]。后续研究表明,这些泥质和砂质相连同夹杂其中的粉砂质等深流相,通常出现在厚度仅几分米的复合序列或部分序列中(典型范围 0.5 3 m 0.5 3 m 0.5-3m0.5-3 \mathrm{~m} )。现行标准的双向渐变相模型显示整体负向分级(由细变粗),从泥质通过粉砂斑驳到砂质等深流相,然后正向分级(由粗变细)回到粉砂斑驳再到泥质等深流相[116]。明确的沉积结构通常缺失,部分原因是被生物扰动彻底破坏。可能存在不清晰且不连续的平行层理以及较粗物质的透镜体。原生结构,包括罕见的交错层理,在粗粉砂和砂中比在细粒相中更为明显。该模型适用于所有成分类型。
Components of a complete sequence are referred to by the notation C1-5, as illustrated in Figure 13, after [28]. Partial sequences are very common in which divisions occur in the same order but with the omission of one or more divisions. Top-cut-out sequences reflect the abrupt truncation of the full sequence, whereas base-cut-out sequences reflect the gradual onset in deposition after a period of erosion. Partial sequences can occur downstream of a narrow gateway or channel, with middle-only sequences deposited proximally and top/base only sequences more distally. Base-only partial sequences are referred to as C1, C1-2 or C1-3, and top-only sequences as C3-5, C4-5 or C5, as appropriate.
完整序列的组成部分用符号 C1-5 表示,如图 13 所示,参考文献[28]。部分序列非常常见,其划分顺序相同,但省略了一个或多个部分。顶部截断序列反映了完整序列的突然截断,而底部截断序列则反映了经历一段侵蚀期后沉积的逐渐开始。部分序列可能出现在狭窄通道或水道的下游,近端沉积中间部分序列,远端则沉积顶部或底部序列。仅底部的部分序列称为 C1、C1-2 或 C1-3,顶部序列称为 C3-5、C4-5 或 C5,视具体情况而定。
The principal controls on deposition of the bi-gradational sequence are (a) long-term variation in mean bottom-current velocity and (b) episodic variation of sediment input [63,66,116,117]. A lower mean current speed leads to mud transport and deposition (C1 and C5 divisions), whereas higher speeds deposit sands (C3 division). Alternatively, a periodic supply of coarser (sandy) material can be from lateral input by turbidity currents, for example, or by enhanced vertical settling of sand-sized biogenic material during periods of high surface productivity. Contourite sequences show a more or less regular cyclicity, typically between 5000 and 20,000 years, which may be related to an interaction of the two dominant controls.
生物渐变序列沉积的主要控制因素是(a)长期平均底流速度的变化和(b)沉积物输入的间歇性变化[63,66,116,117]。较低的平均流速导致泥质物质的运输和沉积(C1 和 C5 层),而较高的流速则沉积砂质物质(C3 层)。另外,较粗(砂质)物质的周期性供应可能来自侧向的浊流输入,例如,或在表层生产力高的时期通过增强的砂粒级生物物质垂直沉降。等流沉积序列表现出或多或少的规律性周期,通常在 5000 至 20000 年之间,这可能与两种主要控制因素的相互作用有关。
Contourite sands occur as part of the bi-gradational sequence or partial sequences (the C3 division) in mud-rich drifts, where they are relatively poorly-sorted and bioturbated, with or without some lamination and cross-lamination preserved. However, they also occur independently in sand sheets and contourite channels, where they are not part of a standard contourite sequence. Three different sandy contourite types (or facies models) are recognised (Figure 14), namely, (a) fine-grained bioturbated sandy facies, with some mud; (b) fine to medium-grained, clean (mud-free) sands that are mostly structureless sands with rare bioturbation and lamination; and © medium- to coarse-grained, laminated and cross-bedded sands that are mud-free and generally without bioturbation. They may contain pebbly horizons.
轮廓沉积砂作为泥质漂积物中双渐变序列或部分序列(C3 部分)的一部分出现,其颗粒分选较差且受生物扰动,可能带有或不带有一定的层理和交错层理。然而,它们也独立存在于砂层和轮廓沉积通道中,此时不属于标准的轮廓沉积序列。识别出三种不同的砂质轮廓沉积类型(或相模型)(图 14),即:(a)含有一定泥质的细粒生物扰动砂相;(b)细至中粒、干净(无泥)砂,主要为无结构砂,偶有生物扰动和层理;(c)中至粗粒、带层理和交错层理的砂,干净且通常无生物扰动,可能含有砾石层。

5. Hemipelagic Deposits  5. 半深海沉积物

5.1. Definition and Facies
5.1. 定义与相特征

Hemipelagites are fine-grained sediments, typically muds and sandy muds, which comprise mixtures of terrigenous and biogenic material, of which the terrigenous component is silt-rich. They are deposited by a combination of vertical settling and very slow lateral advection [70]. Hemipelagites are one of the principal marine sediment types covering large tracts of continental margins worldwide and forming the ‘background’ facies of many deep-water successions [1,4,17]. Many black-shale source rocks and organic-rich shale-gas reservoirs are largely of hemipelagic origin, although other processes may also be involved in the deposition of black shales [118].
半陆相沉积物是细粒沉积物,通常为泥质和砂质泥,包含陆源和生物源物质的混合物,其中陆源成分富含粉砂。它们通过垂直沉降和非常缓慢的横向平流共同沉积[70]。半陆相沉积物是覆盖全球大陆边缘大片区域的主要海洋沉积类型之一,构成许多深水地层的“背景”相[1,4,17]。许多黑色页岩烃源岩和富有机质的页岩气储层主要起源于半陆相沉积,尽管黑色页岩的沉积也可能涉及其他过程[118]。
More specifically, hemipelagites are defined as fine-grained sediments that are typical of marginal outer shelf and slope settings. They comprise an admixture of biogenic pelagic material (generally > 10 % > 10 % > 10%>10 \% ) and terrigenous or volcaniclastic material (generally > 10 % > 10 % > 10%>10 \% ), in which a significant proportion ( > 40 % > 40 % > 40%>40 \% ) of the terrigenous (or volcaniclastic) fraction is silt-size or greater ( > 4 μ m > 4 μ m > 4mum>4 \mu \mathrm{~m} ).
更具体地说,半陆相沉积物被定义为典型于边缘外陆架和坡地环境的细粒沉积物。它们由生物源远洋物质(通常为 > 10 % > 10 % > 10%>10 \% )和陆源或火山碎屑物质(通常为 > 10 % > 10 % > 10%>10 \% )的混合物组成,其中陆源(或火山碎屑)部分中有相当比例( > 40 % > 40 % > 40%>40 \% )为粉砂粒径或更大( > 4 μ m > 4 μ m > 4mum>4 \mu \mathrm{~m} )。
This definition follows closely that from several earlier attempts to characterise the widespread ‘background’ sediment in many deep-water settings that are similar to open-ocean pelagic facies, but with a greater input from siliciclastic (and/or volcaniclastic) material from land [ 17 , 119 , 120 ] [ 17 , 119 , 120 ] [17,119,120][17,119,120]. They also have a far greater rate of sedimentation (typically 5 15 cm ka 1 5 15 cm ka 1 5-15cmka^(-1)5-15 \mathrm{~cm} \mathrm{ka}^{-1} ) than pelagic sediments (typically < 1 cm ka 1 < 1 cm ka 1 < 1cmka^(-1)<1 \mathrm{~cm} \mathrm{ka}^{-1} ) and are more likely to preserve organic carbon [118,121].
该定义紧随早期几次尝试对许多深水环境中广泛存在的“背景”沉积物进行表征的定义,这些沉积物类似于开阔海洋的远洋沉积相,但陆地硅质碎屑(和/或火山碎屑)物质的输入更多 [ 17 , 119 , 120 ] [ 17 , 119 , 120 ] [17,119,120][17,119,120] 。它们的沉积速率也远高于远洋沉积物(通常为 5 15 cm ka 1 5 15 cm ka 1 5-15cmka^(-1)5-15 \mathrm{~cm} \mathrm{ka}^{-1} ,而远洋沉积物通常为 < 1 cm ka 1 < 1 cm ka 1 < 1cmka^(-1)<1 \mathrm{~cm} \mathrm{ka}^{-1} ),且更有可能保存有机碳[118,121]。
Hemipelagites have close similarities with other deep-water facies with which they are commonly associated, including (a) pelagites, both biogenic oozes and abyssal red clays; (b) muddy contourites; © fine-grained turbidites; and (d) hemiturbidites. There is a complete gradation between hemipelagites and muddy contourites, as bottom-current velocity increases, and open ocean pelagites, with increasing distance from land and diminishing terrestrial input. Hemiturbidites are sediments with partly muddy turbidite and partly hemipelagite characteristics [32].
半远洋沉积物与其常见的其他深水沉积相有密切相似性,包括(a)远洋沉积物,既有生物源泥浆也有深渊红粘土;(b)泥质等深流沉积物;(c)细粒浊积岩;以及(d)半浊积岩。随着底流速度的增加,半远洋沉积物与泥质等深流沉积物之间存在完全的渐变;随着距陆地距离的增加和陆源输入的减少,半远洋沉积物与开阔海洋远洋沉积物之间也存在渐变。半浊积岩是具有部分泥质浊积岩和部分半远洋沉积物特征的沉积物[32]。
We show the principal facies models for hemipelagites in Figure 17. The deposit characteristics, as described below, are illustrated with photographs in Figure 18.
我们在图 17 中展示了半远洋沉积物的主要沉积相模型。下文所述的沉积特征在图 18 的照片中有所展示。
HEMIPELAGITE FACIES MODELS: Fine-grained, mixed-composition hemipelagites
半陆相沉积相模型:细粒、混合成分的半陆相沉积物

Figure 17. Hemipelagite facies models. The standard model shows simple compositional cyclicity between more clay-rich and more biogenic-rich parts. Variations depend on the input of different components.
图 17. 半陆相沉积相模型。标准模型显示了富含粘土和富含生物成分部分之间的简单成分周期性变化。变化取决于不同成分的输入。

Figure 18. Cont.  图 18. 续。
Figure 18. Hemipelagite and pelagite family: photographic examples. (A) Typical bioturbated and colour-varied hemipelagites, IODP Site 1385 (Expedition 339), offshore SW Portugal. (B) Carbonate-rich (whitish) and clay-rich (brownish) hemipelagite-pelagite facies, central Argentine Abyssal Plain. Dark grey/black horizons are iron-manganese-rich layers, which may indicate the influence of weak bottom currents. © Bioturbated hemipelagites-pelagites (whitish) interbedded with graded mud turbidites (dark brown), Plio-Pleistocene, DSDP Site 530, SE Angola Basin, S Atlantic. (D) Detail from succession as above, hemipelagite over turbidite with intense bioturbation. (E) Pelagite (micritic limestone), Eocene, Petra tou Romiou, southern Cyprus. Some evidence for interbedding with fine calcareous contourites, i.e., small bi-gradational sequence from calcilutite to calcisiltite and back to calcilutite (marked with a black line). (F) Pelagite, white micritic limestone (chalk) and black chert nodule (from siliceous pelagite), Durdle Door, Dorset, southern England. (G) Hemipelagite (pale) interbedded and inter-bioturbated with volcaniclastic ash layers (dark). Some evidence of possible transport by bottom currents. Miocene Misaki Formation, Miura, Japan. (H) Pelagites: interbedded limestone (white) and organic-rich chert (black) beds, Cretaceous, central Umbria, Italy. Core width 10 cm in (a-d).
图 18. 半远洋沉积物和远洋沉积物家族:照片示例。(A) 典型的生物扰动和颜色多样的半远洋沉积物,IODP 1385 站点(第 339 次航次),葡萄牙西南海域。(B) 富含碳酸盐(白色)和富含粘土(棕色)的半远洋-远洋沉积相,阿根廷中央深海平原。深灰/黑色层位为富铁锰层,可能表明弱底流的影响。(C) 生物扰动的半远洋-远洋沉积物(白色)与分级泥质浊积岩(深棕色)交错层理,更新世-上新世,DSDP 530 站点,安哥拉盆地东南部,南大西洋。(D) 上述地层的细节,半远洋沉积物覆盖强烈生物扰动的浊积岩。(E) 远洋沉积物(微晶灰岩),始新世,塞浦路斯南部 Petra tou Romiou。部分证据显示与细粒碳酸盐轮廓沉积物交错层理,即从钙泥岩到钙粉砂岩再回到钙泥岩的小型渐变序列(以黑线标记)。(F) 远洋沉积物,白色微晶灰岩(白垩)和黑色燧石结核(来自硅质远洋沉积物),英国南部多塞特郡 Durdle Door。(G) 半远洋沉积物(浅色)与火山碎屑灰层(深色)交错且相互生物扰动。 一些可能由底流搬运的证据。中新世三崎组,日本三浦。(H)远洋沉积物:夹层石灰岩(白色)和富有机质的燧石(黑色)层,白垩纪,意大利翁布里亚中部。(a-d)中岩心宽度为 10 厘米。

5.2. Hemipelagic Characteristics
5.2. 半远洋沉积物特征

Bedding. There is an absence or indistinctness of beds in thick successions of modern hemipelagites, where the subtle, often cyclic, variation in composition can lead to a cyclic colour variation (bedding) [1, 17,70]. Typically, the composition varies between more and less carbonate/biogenic-rich or more and less organic-carbon-rich, yielding darker and lighter-coloured beds with intensely bioturbated and gradational contacts. However, burial, compaction and diagenesis can then produce a much more distinctly bedded succession. Furthermore, where hemipelagites are interbedded with other facies (turbidites, for example), the overall succession becomes well bedded.
层理。在现代厚厚的半远洋沉积物中,层理缺失或不明显,其中成分的细微且常呈周期性变化可导致周期性色彩变化(层理)[1, 17,70]。通常,成分在更多或更少的碳酸盐/生物源物质和更多或更少的有机碳之间变化,形成颜色较深和较浅的层,层与层之间生物扰动强烈且接触渐变。然而,埋藏、压实和成岩作用随后可产生更明显的层理序列。此外,当半远洋沉积物与其他相(例如浊积岩)交错时,整体地层序列表现出良好的层理。
Structures. Primary sedimentary structures are completely absent in those hemipelagites deposited in oxygenated water. There is no current activity and a complete bioturbational overturn has served to homogenise the sediment. Where bottom waters are low in oxygen, then parallel lamination may be preserved, with low to absent bioturbation [122,123]. This is most typically a fissile lamination with laminae showing a sub-parallel, wavy, anastomosing pattern [124]. Lamination is best developed in completely anoxic conditions and under high rates of sedimentation, but shows no evidence of current influence.
结构。在氧化水体中沉积的半陆相沉积物中,完全不存在原生沉积结构。没有水流活动,完全的生物扰动翻转使沉积物均质化。在底水缺氧的情况下,可能保留平行层理,生物扰动较少或缺失[122,123]。这通常表现为易裂层理,层理呈亚平行、波状、网状交织的模式[124]。层理在完全缺氧条件下和高沉积速率下发育最佳,但无水流影响的证据。
Bioturbation. Pervasive, high-intensity and diverse bioturbation is typical for hemipelagites deposited under normal oxygenated conditions, commonly with depth-related zonation or tiering evident [125,126]. It is characterised by the Zoophycos and Nereites ichnofacies, within which traces include Zoophycos, Chondrites, Planolites, Thalassinoides and Phycosiphon, as well as many others. Trace fossil zonation, with multiple tiering, is most evident in more rapidly deposited hemipelagites, especially where they are interbedded with turbidites. Complete bioturbational mottling is more common under slow rates of deposition. During the transition from fully oxygenated to low-oxygen and anoxic conditions, ichnofossils decrease in size, abundance and diversity, from a highly mixed assemblage through to no bioturbation [127].
生物扰动。广泛、高强度且多样化的生物扰动是正常含氧条件下沉积的半陆源沉积物的典型特征,通常表现出与深度相关的分带或分层现象[125,126]。其特征为 Zoophycos 和 Nereites 生痕化石群,其中的痕迹包括 Zoophycos、Chondrites、Planolites、Thalassinoides 和 Phycosiphon 等多种。生痕化石的分带及多层次分层在沉积较快的半陆源沉积物中尤为明显,特别是在与浊积岩交错出现时。完全的生物扰动斑驳在沉积速率较慢时更为常见。在从完全含氧向低氧及缺氧条件过渡的过程中,生痕化石的大小、数量和多样性逐渐减少,从高度混合的组合体逐渐减少至无生物扰动[127]。
Texture. Grain size characteristics of hemipelagites are strongly influenced by their composition as well as by distance from source. They are mostly fine-grained (mean 5 35 μ m 5 35 μ m 5-35 mum5-35 \mu \mathrm{~m} ) and poorly sorted, and have a broad spread of grain sizes, including bimodal, trimodal and polymodal distributions. Skewness is normal to slightly fine-skewed, and most distributions are more or less platykurtic. The fine silt mode ( 5 10 μ m 5 10 μ m 5-10 mum5-10 \mu \mathrm{~m} ) is most common, reflecting dominant nannofossil contribution. Modes at medium to coarse silt sizes reflect specific inputs of fluvial, eolian, volcanic or glacial material, whereas coarse silt and fine sand modes are more likely related to different biogenic pelagic components (foraminifers, radiolarians and diatoms). Coarser grains are introduced, in particular, by ice rafting at high latitudes and by volcaniclastic activity.
质地。半陆相沉积物的粒度特征受其组成以及距源距离的强烈影响。它们大多为细粒(平均 5 35 μ m 5 35 μ m 5-35 mum5-35 \mu \mathrm{~m} )且分选较差,粒径分布范围广泛,包括双峰、三峰和多峰分布。偏度为正态至略偏细粒,大多数分布或多或少呈现低峰态。细粉砂模式( 5 10 μ m 5 10 μ m 5-10 mum5-10 \mu \mathrm{~m} )最为常见,反映了纳诺化石的主导贡献。中到粗粉砂的模式反映了河流、风成、火山或冰川物质的特定输入,而粗粉砂和细砂模式更可能与不同的生物源远洋成分(有孔虫、放射虫和硅藻)相关。较粗的颗粒尤其由高纬度的冰筏作用和火山碎屑活动引入。
Fabric. Contrary to earlier studies that suggested a well-aligned fabric [70], more recent work indicates that hemipelagites are characterised by random to semi-random silt and clay fabrics [114]. The lack of a well-aligned microfabric is further accentuated by the presence of isolated large grains as well as by intense bioturbation.
结构。与早期研究提出的具有良好排列结构[70]相反,最新研究表明半陆相沉积物的粉砂和粘土结构呈随机到半随机分布[114]。孤立的大颗粒存在以及强烈的生物扰动进一步加剧了缺乏良好排列微观结构的特征。
Composition. Hemipelagites, by definition, have a mixed composition [70,119,128]. Biogenic components are dominated by open ocean planktonic microfossils, either calcareous (nannofossils and foraminiferans) or siliceous (radiolarians and diatoms). More minor amounts of other biogenic material, including sponge, spicules, dinoflagellates, silicoflagellates, benthic foraminiferans and a variety of macrofossils, may also be present. Terrigenous components depend on the source area and supply. Clay minerals and silt-sized siliciclastics (quartz and feldspar, etc.) are derived from river plumes and winds; the latter may also introduce chemogenic particles. Lithic grains and an immature mineral assemblage are typical of ice-rafted debris. Volcaniclastic particles may dominate in island arc settings around volcanic seamounts and plateaus. Chemogenic components form authigenically in slowly accumulating hemipelagites, including ferromanganese nodules, phosphorites and glauconite.
组成。半陆相沉积物,按定义,具有混合成分[70,119,128]。生物成分以远洋浮游微体化石为主,既有钙质的(纳米化石和有孔虫),也有硅质的(放射虫和硅藻)。还可能含有较少量的其他生物成分,包括海绵针、鞭毛虫、硅鞭毛虫、底栖有孔虫以及各种大型化石。陆源成分取决于源区和供应。粘土矿物和粉砂级硅质碎屑(石英和长石等)来自河流羽流和风力输送;后者还可能引入化学成因颗粒。岩屑颗粒和未成熟矿物组合是冰漂碎屑的典型特征。火山碎屑颗粒可能在火山海山和高原周围的岛弧环境中占主导。化学成因成分在缓慢沉积的半陆相沉积物中自生形成,包括铁锰结核、磷灰石和绿泥石。
Total organic carbon content, although generally very low, may be significantly higher ( 1 10 % 1 10 % 1-10%1-10 \% ) in areas of enhanced preservation of organic matter [129,130]. These include regions of high primary productivity in surface waters (upwelling zones), low bottom-water oxygenation (semi-enclosed basin
总有机碳含量虽然通常非常低,但在有机质保存增强的区域可能显著更高( 1 10 % 1 10 % 1-10%1-10 \% )[129,130]。这些区域包括表层水体初级生产力高的地区(上升流区)、底层水体氧气含量低的半封闭盆地

and, mid-water oxygen minima) and high influx of organic matter from land or via turbidity currents. High total organic carbon is especially characteristic of laminated hemipelagites deposited under anoxic conditions.
以及中层水体氧气极小区,还有来自陆地或通过浊流输入的有机质量高的区域。高总有机碳含量尤其是缺氧条件下沉积的层理半深海沉积物的典型特征。

5.3. Hemipelagic Facies Models
5.3. 半深海相模型

Hemipelagite is often considered to be a rather elusive sediment facies and almost a bucket-term for a wide range of sediment types that form background deposits over large tracts of the continental shelf and slope and in many marginal or confined basins. An estimated 15 20 % 15 20 % 15-20%15-20 \% of the present-day seafloor is composed of hemipelagites, and, volumetrically, they are still more abundant because of their great thicknesses along continental margins. Many modern examples have been described from around the world, some of which are summarised in [70]. Limestone-marl cyclic sedimentation is commonly reported from ancient successions (see papers in [131,132]) in which the marlstone units are hemipelagic and the limestones pelagic in nature. Interbedded turbidites and hemipelagites have been described in detail in [91,133], together with the distinguishing features between the two facies types.
半陆相沉积物通常被认为是一种相当难以捉摸的沉积相,几乎成为涵盖广泛沉积类型的统称,这些沉积类型形成了大陆架和大陆坡大面积的背景沉积,以及许多边缘或受限盆地的沉积。估计现今海底约有 15 20 % 15 20 % 15-20%15-20 \% 由半陆相沉积物组成,从体积上看,由于其在大陆边缘的巨大厚度,半陆相沉积物仍然更为丰富。世界各地已有许多现代实例被描述,其中一些在[70]中有所总结。古代地层中常见石灰岩-泥灰岩的周期性沉积(见[131,132]中的论文),其中泥灰岩单元为半陆相性质,石灰岩则为远洋相性质。[91,133]中详细描述了夹层的浊积岩和半陆相沉积物,并阐明了这两种沉积相类型的区别特征。
There have been, however, few attempts to develop a comprehensive facies model for hemipelagites [ 4 , 15 , 115 ] [ 4 , 15 , 115 ] [4,15,115][4,15,115]. A more recent refinement of the model elucidates the detailed facies characteristics and better represents the variety of hemipelagic facies that exist [70]. Further detailed observations of a typical hemipelagic succession offshore of SW Iberia are provided by [134]. The composite facies model shown in Figure 17, together with its several variations, has been compiled from this earlier work and represents the detailed characteristics outlined above.
然而,关于半陆相沉积物的综合相模型的研究尝试很少 [ 4 , 15 , 115 ] [ 4 , 15 , 115 ] [4,15,115][4,15,115] 。该模型的最新改进阐明了详细的相特征,并更好地反映了存在的多种半陆相相[70]。关于西南伊比利亚海岸外典型半陆相地层的进一步详细观察见文献[134]。图 17 所示的综合相模型及其若干变体,汇编自上述早期研究,代表了上述详细特征。
Hemipelagites are fine-grained sediments, widespread over the shelf, slope and marginal basin settings. The standard facies model in Figure 17 shows indistinct bedding based on compositional (and colour) variation, with gradational contacts between beds due to extensive bioturbational mixing. Compaction, burial and diagenesis commonly accentuate such differences and yield a more well-bedded succession but retain the cyclicity in composition/colour. There are no primary sedimentary structures but a pervasive bioturbation with a high diversity of trace fossils in the Zoophycos-Nereites ichnofacies occurs. A tiered trace-fossil zonation is common where the rate of accumulation is more rapid. The mean size is fine ( 5 35 μ m ) ( 5 35 μ m ) (5-35 mum)(5-35 \mu \mathrm{~m}) and the sediment poorly sorted, with a bimodal to polymodal, mesokurtic to platykurtic distribution. The microfabric is random to semi-random. Composition is mixed biogenic and terrigenous, mostly supplied from the surface waters by vertical settling and slow lateral advection.
半陆相沉积物是细粒沉积物,广泛分布于陆架、陆坡和边缘盆地环境中。图 17 中的标准相模型显示基于成分(和颜色)变化的模糊层理,层与层之间因广泛的生物扰动混合而呈渐变接触。压实、埋藏和成岩作用通常会加剧这些差异,形成更明显的层理,但仍保留成分/颜色的周期性。没有原生沉积结构,但普遍存在生物扰动,并伴有 Zoophycos-Nereites 迹化石群中高多样性的迹化石。在沉积速率较快的情况下,常见分层的迹化石带。平均粒径为细粒 ( 5 35 μ m ) ( 5 35 μ m ) (5-35 mum)(5-35 \mu \mathrm{~m}) ,沉积物分选较差,呈双峰到多峰分布,峰度介于中峰态到低峰态之间。微观结构为随机到半随机。成分为混合的生物源和陆源物质,主要通过垂直沉降和缓慢的横向输送从表层水体供应。
Variations from the standard model are also shown in Figures 17 and 18. These illustrate some of the variability that exists due to compositional differences. Glacigenic hemipelagites at high latitudes are dominated by terrigenous material derived from ice rafting and by very poor sorting. Biogenic-rich hemipelagites are typical of low latitudes and upwelling zones, with little fluvial supply. Horizons with a reddish hue may indicate periods of time with a greater influx of wind-blown material (rich in iron-III). Volcaniclastic hemipelagites have an interspersed and poorly-sorted admixture of volcanic debris. Organic-rich hemipelagites have a darker grey-black colour and may display distinctive fissile lamination, with an absence of bioturbation where deposited under anoxic conditions. Cyclic variation of composition and colour is the norm for all types of hemipelagites, and is most commonly linked to climatic cyclicity.
图 17 和图 18 中也展示了与标准模型的变异情况。这些图说明了由于成分差异而存在的一些变异性。高纬度的冰川源半盆地沉积物主要由冰筏运输的陆源物质组成,且分选极差。富含生物成分的半盆地沉积物典型于低纬度和上升流区,河流输入较少。带有红色调的地层可能表明风吹物质(富含三价铁)输入较多的时期。火山碎屑半盆地沉积物夹杂有分布不均且分选较差的火山碎屑。富含有机质的半盆地沉积物呈较深的灰黑色,可能显示出明显的易裂层理,且在缺氧条件下沉积时无生物扰动。所有类型的半盆地沉积物成分和颜色的周期性变化是常态,且最常与气候周期性相关。

6. Hybrid Deposits  6. 混合沉积物

Hybrid deposits (in deep-water) can be defined as those sediments showing characteristics intermediate between the deposits that are typical of other deep-water facies, namely, turbidites, contourites and hemipelagites. They result from process interaction, flow transformation and seafloor reworking of earlier deposits. A range of different types have been identified, but they are not necessarily easy to recognise from their mixed characteristics.
混合沉积物(深水中)可以定义为那些显示出介于其他典型深水相沉积物之间特征的沉积物,即浊积岩、轮廓流沉积物和半盆地沉积物。它们是由过程相互作用、流动转变以及对早期沉积物的海底再加工形成的。已经识别出多种不同类型,但由于其混合特性,它们不一定容易被识别。
Hemiturbidites were first described from the distal Bengal Fan in the Indian Ocean [32], where they result from the progressive dilution and flow lofting of very low-concentration turbidity currents [33]
半浊积岩最早在印度洋孟加拉扇的远端被描述[32],在那里它们是由极低浓度浊积流的逐渐稀释和流体上升[33]

and upward mixing into the overlying water column, leading to a process of mixed hemipelagic and turbiditic settling. The generally thick-bedded deposits are very fine-grained silty muds, with a mixed turbidite-hemipelagite composition and pervasive bioturbation throughout.
以及向上混入上覆水柱中形成的,导致半盆地沉积与浊积沉积混合沉降的过程。通常厚层沉积物为非常细粒的粉质泥,具有混合的浊积岩-半盆地沉积物组成,并且贯穿始终存在广泛的生物扰动。
Hybrid event beds, as defined by [34], are the result of flow transformation within downslope gravity flows (or composite flows). These flows show an increase in concentration distally, meaning the high-concentration turbidity current transforms, in part, into a mudflow or debris flow. The resultant hybrid event bed typically shows a massive or laminated sandstone turbidite overlain by a debrite, as well as other hybrid variations [1,37]. A similar process of flow transformation was proposed by [72] to explain very thick-bedded structureless muds in distal basin-plain settings. In this case, a low-concentration turbidity current transforms into a highly-concentrated mudflow.
混合事件层床,如[34]所定义,是坡下重力流(或复合流)内流动转变的结果。这些流在远端表现出浓度的增加,意味着高浓度的浊流部分转变为泥流或碎屑流。由此形成的混合事件层床通常表现为一层厚实或层理的砂岩浊积岩,上覆一层碎屑流沉积物,以及其他混合变体[1,37]。[72]提出了类似的流动转变过程,以解释远端盆地平原环境中非常厚的无结构泥质沉积物。在这种情况下,低浓度的浊流转变为高浓度的泥流。
Bottom-current reworked pelagites and hemipelagites commonly occur where weak bottom currents interact with the background vertical settling processes in the open ocean, and gently winnow and rework the deposits. This may be evident from local winnowing and concentration of foraminiferal sands, regional variations in thickness, and/or widespread hiatuses. Reeder et al. [135] has interpreted the relatively high rates of hemipelagic accumulation in the Sicily gateway as the result of bottom-current lofting and re-suspension of the bottom-current load into the overlying water column. Marked thickness variations in mid-ocean pelagic successions, as noted by [136], can be interpreted as a weak bottom-current influence on an otherwise normal pelagite facies.
底流重塑的远洋沉积物和半远洋沉积物通常出现在弱底流与开放海洋中背景垂直沉降过程相互作用的区域,底流轻微筛选并重塑沉积物。这可能通过局部筛选和有孔虫砂的集中、厚度的区域变化和/或广泛的缺失层表现出来。Reeder 等人[135]将西西里通道半远洋沉积速率相对较高解释为底流将底流负载物扬起并重新悬浮到上覆水柱中的结果。正如[136]所指出的,中洋远洋沉积层的显著厚度变化可以解释为弱底流对本应为正常远洋沉积相的影响。
Bottom-current reworked turbidites have proved more difficult to identify with certainty. Some good modern examples have been described from the Columbia gateway in the SW Atlantic [137-139], the Tanzanian margin [140] and the Sicily gateway in the Mediterranean [135]. Some of the sediments described from mixed drift systems, such as those on the Antarctic Peninsula margin [141] and Tanzanian margin [140], have been interpreted as the result of sediment supply from turbidity currents, followed by the capture of the fine suspended cloud by active bottom currents. This material is then deposited at varying distances from the supply channel across the adjacent levees or mixed drift bodies in a down-current direction. They show clear, but somewhat irregular lamination coupled with bioturbation where lamination is less pronounced. Bulk grain-size analysis shows a very poorly sorted silty clay grain size, although individual silty laminae are no doubt slightly coarser grained. A mixed turbidite/contourite facies type seems reasonable.
经底流重塑的浊积岩更难以确定识别。一些较好的现代实例已在西南大西洋的哥伦比亚通道[137-139]、坦桑尼亚大陆边缘[140]以及地中海的西西里通道[135]被描述。从混合漂积系统中描述的一些沉积物,如南极半岛大陆边缘[141]和坦桑尼亚大陆边缘[140],被解释为浊积流提供沉积物,随后活跃的底流捕获细悬浮云所致。这些物质随后沿着供应通道下游方向,在相邻的堤岸或混合漂积体上不同距离处沉积。它们显示出清晰但略显不规则的层理,并伴有生物扰动,层理较不明显处尤为如此。整体粒度分析显示为极差选的粉质粘土粒度,尽管单个粉质层理无疑粒度稍粗。混合浊积岩/轮廓流相类型似乎合理。
We therefore recognise three different types of these hybrid turbidite-contourite beds that result from (a) short lateral diversion of a turbidity current by a bottom current (e.g., forming asymmetric levees), with little change to the fine-grained turbidite deposited; (b) longer-distance bottom-current transport of sediment captured from the top/tail of a turbidity current, yielding a deposit with turbidite composition and contourite characteristics (e.g., mixed drifts); and © reworking of the tops of already deposited turbidites by strong bottom currents, which can cause winnowing and cleaning of the turbidite sands, removal of the upper turbidite divisions or the superposition of contourite sands, muds and/or bioturbation.
因此,我们识别出三种不同类型的混合型浊积岩-轮廓沉积床,这些类型分别源于:(a) 底流对浊积流的短距离横向偏转(例如,形成不对称堤坝),对沉积的细粒浊积岩几乎没有影响;(b) 底流对从浊积流顶部或尾部捕获的沉积物进行长距离运输,形成具有浊积岩成分和轮廓沉积特征的沉积物(例如,混合漂积物);以及 (c) 强底流对已沉积浊积岩顶部的再加工,可能导致浊积砂的筛选和清理、上部浊积层的移除,或轮廓砂、泥及/或生物扰动的叠加。

7. Discussion  7. 讨论

7.1. Controversy  7.1. 争议

The processes and facies characteristics of turbidites, contourites and hemipelagites, as outlined above, are each quite different from one another, much like apples and oranges! In theory, therefore, it should be relatively easy to distinguish between them. Turbidity currents are single, episodic events that result in a geologically instantaneous deposit (over minutes to days). For the most part, they are relatively high-energy, downslope currents capable of marked seafloor erosion as well as deposition. Bottom currents are continuous over long periods of time (over millions of years), with relatively slow accumulation of contourite deposits under low-energy alongslope currents, except where higher flow velocity causes a temporary hiatus or erosion. Hemipelagic settling is a continuous low-energy process
如上所述,浊积岩、轮廓沉积物和半盆地沉积物的形成过程及相特征彼此截然不同,就像苹果和橘子一样!因此,理论上应当相对容易区分它们。浊积流是单一的、偶发的事件,导致地质上瞬时的沉积(持续数分钟到数天)。它们大多是相对高能的下坡流,能够显著侵蚀海底并进行沉积。底流则是持续存在的,时间跨度长达数百万年,轮廓沉积物在低能的沿坡流作用下缓慢累积,除非流速较高导致暂时的中断或侵蚀。半盆地沉积是一个持续的低能过程,

that takes place in the absence of current activity, such that hemipelagites accumulate very slowly and continuously (over millions of years).
发生在无流活动的情况下,因此半盆地沉积物以极其缓慢且连续的方式累积(持续数百万年)。
The facies models for the three sediment types, therefore, are distinct and different from each other, and, in many cases, it is quite easy to distinguish between them. However, this is not always so, such that a definitive interpretation may not be possible from the data available, especially when that data is only the small-scale observation of sediment facies and structures in a core or outcrop. It is strongly recommended here that purely speculative interpretations without sufficient evidence are not made. Difficulty and controversy arise for several reasons:
因此,这三种沉积物类型的相模型是各自独特且彼此不同的,在许多情况下,区分它们相当容易。然而,情况并非总是如此,尤其当可用数据仅限于岩心或露头中沉积相和结构的小尺度观察时,可能无法做出明确的解释。这里强烈建议不要在缺乏充分证据的情况下进行纯粹的推测性解释。困难和争议产生的原因有几个:

(1) The processes themselves show a degree of overlap as part of a process continuum, meaning the deposit characteristics also overlap as part of a facies continuum. This is particularly true for distinguishing between fine-grained turbidites and silty-muddy contourites, and also for distinguishing between muddy contourites and hemipelagites.
(1)这些过程本身作为一个过程连续体,表现出一定程度的重叠,这意味着沉积物特征作为相连续体也存在重叠。这一点在区分细粒浊积岩和粉砂-泥质轮廓沉积物,以及区分泥质轮廓沉积物和半盆地沉积物时尤为明显。

(2) The three facies types commonly occur closely interbedded in continental margin deposits. Episodic turbidites are blanketed by hemipelagites in some slope settings, and interbedded with contourites in other cases. Muddy contourites deposited by weak bottom currents are almost indistinguishable from interbedded hemipelagites.
(2) 这三种相类型通常在大陆边缘沉积物中紧密互层。在某些坡地环境中,间歇性浊积岩被半盆地沉积物覆盖,而在其他情况下则与轮廓流沉积物互层。由弱底流沉积的泥质轮廓流沉积物几乎无法与互层的半盆地沉积物区分开来。

(3) Strong bottom currents can winnow, erode and partially or completely rework turbidites. However, very similar erosion and reworking of turbidites can be caused by subsequent by-passing turbidity currents flowing over the pre-existing deposit. It is not easy to distinguish between these two events, especially where the composition of material moved or reworked by the different currents is the same.
(3) 强烈的底流可以筛选、侵蚀并部分或完全重塑浊积岩。然而,随后流经已有沉积物的浊浊流也能引起非常相似的浊积岩侵蚀和重塑。区分这两种事件并不容易,尤其是在不同流体移动或重塑的物质成分相同时。

(4) There is a significant amount of contradictory information in the literature. Some authors claim that traction structures are widespread in all contourites, as though tractional movement of sediment were the preserve of bottom currents (e.g., [6,142]). In fact, neither contention is true. Primary structures are either not present or largely destroyed by bioturbation in finer-grained contourites, whereas they may be preserved in sandy contourites. The lamination and cross-lamination in turbidites is also the result of bedload traction. The simplistic diagrams showing sedimentary structures interpreted as diagnostic of contourites (e.g., [6,142,143]) are very misleading, as all the structures depicted can equally be generated by turbidity currents and many by other processes as well.
(4)文献中存在大量矛盾的信息。一些作者声称牵引结构在所有等深流沉积物中普遍存在,仿佛沉积物的牵引运动是底流的专属现象(例如,[6,142])。实际上,这两种说法都不正确。细粒等深流沉积物中,原生结构要么不存在,要么被生物扰动大部分破坏,而在砂质等深流沉积物中则可能得以保存。浊积岩中的层理和交错层理同样是床载牵引的结果。那些将沉积结构解释为等深流诊断特征的简化图示(例如,[6,142,143])非常具有误导性,因为图中展示的所有结构同样可以由浊积流产生,且许多结构也可由其他过程形成。

(5) Individual sedimentary characteristics, such as parallel lamination, cross-bedding and structureless muds/sands, can occur in almost every environment. Even combinations of several features are not definitive. Heterolithic facies with silt/sand laminae and micro-cross-lamination with interlaminated mud (e.g., fading ripples) are typical of fine-grained turbidites, but similar facies are also common in tidal and deltaic settings. Dune cross-bedded sands may be typical of some sandy contourites, and only rare in turbidites, but they are also common on the floors of turbidity current channels, in estuarine and other shallow-water nearshore and shelf deposits and in fluvial and eolian environments.
(5) 个别沉积特征,如平行层理、交错层理和无结构的泥质/砂质沉积物,几乎可以出现在所有环境中。即使是多种特征的组合也不能作为决定性依据。含有粉砂/砂质层理和夹层泥质的微交错层理(例如,消退波纹)的异质相相是细粒浊积岩的典型特征,但类似的相也常见于潮汐和三角洲环境中。沙丘交错层理砂岩可能是某些砂质轮廓流沉积物的典型特征,在浊积岩中则较为罕见,但它们也常见于浊积流通道底部、河口及其他浅水近岸和陆架沉积物中,以及河流和风成环境中。
However, as evidenced in this paper, much progress has been made over the past decade in distinguishing between end-member facies in terms of their sedimentary structures, facies sequences, ichnofacies, sediment textures, composition and microfabric. However, equally, it must be acknowledged that clear distinction is not always possible on the basis of sedimentary characteristics alone. In any particular study, the only scientifically valid method to follow, in the absence of definitive evidence, is not to make a single interpretation but to acknowledge and highlight any uncertainties.
然而,正如本文所示,过去十年在区分端元相方面取得了很大进展,这些端元相在沉积结构、相序列、生痕相、沉积物质地、成分和微构造方面各不相同。然而,同样必须承认,仅凭沉积特征并不总能清晰地区分。在任何具体研究中,缺乏确凿证据时,唯一科学有效的方法不是做出单一解释,而是承认并突出任何不确定性。

7.2. Comparing Apples and Oranges
7.2. 比较苹果和橘子

The wide range of facies types within each of the main groups (turbidites, contourites and hemipelagites) is not always fully recognised. Coarse-, medium- and fine-grained turbidites are completely different from one another; for example, a 2 m thick structureless sand and a 2 mm thick wispy silt lamina may both be turbidites, the one very proximal and the other very distal. Taking our apples and oranges metaphor (above), it is tempting to assume that these two facies must be from
在每个主要组(浊积岩、轮廓沉积物和半盆地沉积物)内存在的广泛相类型并不总是被充分认识。粗粒、中粒和细粒浊积岩彼此完全不同;例如,一层 2 米厚的无结构砂和一层 2 毫米厚的细丝状粉砂层都可能是浊积岩,一个非常近源,另一个非常远源。采用我们上文的苹果和橘子比喻,很容易假设这两种相一定来自于

altogether different groups, i.e., turbidites (apples) and contourites (oranges). In fact, they are simply different types of turbidites (apples).
完全不同的群体,即浊积岩(苹果)和轮廓沉积物(橘子)。事实上,它们只是不同类型的浊积岩(苹果)。
We suggest that this error is very often made when attempting to interpret ancient successions on the basis of the appearance of sediment facies or sedimentary structures alone. Very many fine-grained turbidites have been erroneously interpreted as contourites, as carefully documented in [27,28,92,100]. The problems of misinterpretation continue, however, to be exacerbated by the contradictory information in the literature, as highlighted above. Most of the sedimentary structures attributed to contourites by [143,144], especially those depicting thin and very thin beds, are almost certainly due to fine-grained turbidites in our view. We see ample evidence for these structures in turbidite systems (see above), but very few recorded from present-day contourite drifts.
我们认为,当仅根据沉积相或沉积结构的外观来解释古老地层时,这种错误经常发生。许多细粒浊积岩被错误地解释为轮廓沉积物,这在文献[27,28,92,100]中有详细记录。然而,如上所述,文献中矛盾的信息使误解问题持续加剧。我们认为,[143,144]归因于轮廓沉积物的大多数沉积结构,尤其是那些描绘薄层和极薄层的结构,几乎肯定是由细粒浊积岩形成的。我们在浊积岩系统中(见上文)发现了大量这类结构的证据,但在现今的轮廓沉积物堆积区中几乎没有记录。
A further complication arises in determining the depositional process for medium- and thick-bedded sandy facies in deep-water. Parallel-lamination is the norm for turbidite beds with Bouma B-division structures; ripple cross-lamination is typical of Bouma C-division turbidites; and dune-cross bedding is common for by-pass turbidites on channel floors. However, all these structures are now known to occur in sandy contourites [105]. In this case, the apples (turbidites) and oranges (contourites) may actually appear almost identical in their sedimentary characteristics. Guessing an interpretation on the basis of these data alone is not valid. Other criteria must be used where available.
在确定深水中等厚度和厚层砂质相的沉积过程时,出现了进一步的复杂情况。具有 Bouma B 段结构的浊积岩层通常表现为平行层理;Bouma C 段浊积岩典型地表现为波纹交错层理;而通道底部的绕流浊积岩常见沙丘交错层理。然而,现在已知所有这些结构也出现在砂质绕流沉积物中[105]。在这种情况下,苹果(浊积岩)和橙子(绕流沉积物)在沉积特征上实际上可能几乎一模一样。仅凭这些数据进行猜测性解释是不合理的。必须在有条件时使用其他标准。
The Miocene sand-rich succession in the Rifean Corridor, Morocco, with extensive parallel and cross-bedding, was interpreted to be of contourite origin on the basis of careful geological scrutiny and multiple criteria [145]. These included unidirectional cross-bedding and bioturbation, microfossil evidence for deposition at a water depth of 150 300 m 150 300 m 150-300m150-300 \mathrm{~m}, associated facies with bi-gradational sequences typical of mixed contourites, location of the sandstone bodies within a narrow former oceanic gateway between the Atlantic Ocean and Mediterranean Sea, the elongation of these bodies along the length of the gateway and the association of the bodies with several regional hiatuses in the sedimentary record, as well as elongate mounded drifts and moats identified in seismic profiles at the western mouth of the gateway. The authors further concluded that the Rifean Corridor bottom current may have been modulated by a strong deep tidal component.
摩洛哥里费走廊中新近纪富含砂的地层,具有广泛的平行层理和交错层理,经仔细的地质审查和多重标准[145]被解释为轮廓流沉积起源。这些标准包括单向交错层理和生物扰动、微体化石证据表明沉积于 150 300 m 150 300 m 150-300m150-300 \mathrm{~m} 水深、与典型混合轮廓流的双渐变相序列相关的相组合、砂岩体位于大西洋与地中海之间狭窄的前海洋通道内、这些砂岩体沿通道长度方向的延伸,以及砂岩体与沉积记录中多个区域性缺失期的关联,还有在通道西口地震剖面中识别出的细长堆积丘和沟槽。作者进一步得出结论,里费走廊的底流可能受强烈深层潮汐成分的调制。
This interpretation is an example of applying multiple criteria and a three-scale approach, as discussed below.
这一解释是应用多重标准和三尺度方法的一个例子,详见下文讨论。

7.3. Three Scales of Interpretation
7.3. 三个解释尺度

Whereas most turbidites or debrites can be readily identified as such even with cursory field examination, there are others that are so easily designated. Thick structureless sands, parallel-laminated sands and ripple-laminated sands, for example, are found in almost every depositional environment from fluvial to deltaic and from coastal to deep marine. Structureless and bioturbated muds are also commonplace. It is still notoriously difficult to recognize contourite deposits and the influence of bottom currents in ancient successions, and even more so to recognise where a turbidite has been modified by a bottom current or where internal tides and waves have affected the seafloor sediment [143]. There are several simplified schemes published that purport to provide diagnostic criteria for recognizing and differentiating between different deep-water facies (e.g., [60,61,142]. However, careful scrutiny shows them to be wanting and inconclusive [ 27 , 29 , 57 , 100 ] [ 27 , 29 , 57 , 100 ] [27,29,57,100][27,29,57,100].
虽然大多数浊积岩或碎屑岩即使通过粗略的野外检查也能轻易识别,但也有一些并非如此容易区分。例如,厚的无结构砂、平行层理砂和波纹层理砂几乎存在于从河流到三角洲、从沿海到深海的各种沉积环境中。无结构和生物扰动的泥质沉积物也很常见。识别古老地层中的轮廓流沉积物及底流影响仍然极其困难,更难的是识别浊积岩是否被底流改造,或内部潮汐和波浪是否影响了海底沉积物[143]。已有若干简化方案声称能提供识别和区分不同深水相的诊断标准(例如,[60,61,142])。然而,仔细审视后发现这些方案存在不足且结论不明确 [ 27 , 29 , 57 , 100 ] [ 27 , 29 , 57 , 100 ] [27,29,57,100][27,29,57,100]
A logical and scientifically valid three-scale approach is now well accepted by many deep-water specialists for the field identification of ancient contourites [ 87 , 91 , 99 , 138 , 139 , 145 , 146 ] [ 87 , 91 , 99 , 138 , 139 , 145 , 146 ] [87,91,99,138,139,145,146][87,91,99,138,139,145,146]. We here propose that this same approach should be followed wherever possible for all three types of deep-water facies, and have therefore modified and extended the set of criteria to be fulfilled and questions answered, as presented below. This method clearly acknowledges the need to consider all evidence at the small scale (in the field, borehole and through laboratory analysis); at the medium scale (depositional body, formation and region); and at the large scale (sedimentary system, oceanographic and tectonic setting). A similar three-scale approach has also been established for assessing seismic criteria in the recognition of contourite systems [141,147,148].
一种逻辑且科学有效的三尺度方法现已被许多深水专家广泛接受,用于现场识别古代等深流沉积物 [ 87 , 91 , 99 , 138 , 139 , 145 , 146 ] [ 87 , 91 , 99 , 138 , 139 , 145 , 146 ] [87,91,99,138,139,145,146][87,91,99,138,139,145,146] 。我们在此提出,应尽可能对所有三种深水相类型遵循相同的方法,因此对需满足的标准和需回答的问题进行了修改和扩展,具体如下所示。该方法明确承认需要在小尺度(现场、钻孔及实验室分析)、中尺度(沉积体、地层和区域)以及大尺度(沉积系统、海洋学和构造环境)上综合考虑所有证据。类似的三尺度方法也已被建立,用于评估识别等深流系统的地震标准[141,147,148]。
A sequential workflow procedure is suggested below, working from the small to medium to large scale. Of course, it is equally valid to work the other way round, from the large scale to the small scale, or to make observations concurrently. Equally, it is not always possible to consider all attribute types and at all scales of observation, but the more that are available for scrutiny, then the more reliable the interpretation will become.
下面建议一个顺序工作流程,按小尺度到中尺度再到大尺度进行。当然,反过来从大尺度到小尺度工作,或同时进行观察,同样是有效的。同样,也不总是可能考虑所有属性类型和所有观察尺度,但可供审查的属性越多,解释就越可靠。

7.3.1. Small Scale (Field, Borehole and Laboratory Analysis)
7.3.1. 小尺度(现场、钻孔和实验室分析)

  1. Do the sediments have the range of features as described in the text above (Sections 3-5) and illustrated in the facies photographs (Figures 7 , 9 , 12 , 15 , 16 7 , 9 , 12 , 15 , 16 7,9,12,15,167,9,12,15,16 and 18) that are typical of turbidites, contourites or hemipelagites? This necessitates observation of a combination of features, rather than a single attribute, and also multiple observations of a particular characteristic, rather than only one or two examples. More specifically:
    沉积物是否具有上述文本(第 3-5 节)中描述并在相貌照片(图 7 , 9 , 12 , 15 , 16 7 , 9 , 12 , 15 , 16 7,9,12,15,167,9,12,15,16 和 18)中展示的典型浊积岩、轮廓沉积物或半盆地沉积物的特征?这需要观察多种特征的组合,而非单一属性,也需要对某一特征进行多次观察,而非仅一两个例子。更具体地说:

    (a) Sedimentary structures: An assemblage of structures, rather than single structures, is required for more definitive diagnosis, especially the presence of a sequence of structures that match those of the idealised facies models and their variation as partial sequences. Note that structures such as ripple cross-lamination are formed by tractional grain movement at the base of many flow types-turbidity currents, bottom currents, and deep tidal currents, for example.
    (a) 沉积结构:需要一组结构的组合,而非单一结构,才能进行更明确的诊断,尤其是存在一系列与理想化相模型相匹配的结构序列及其作为部分序列的变化。注意,诸如波纹交错层理等结构,是由多种流动类型底部的牵引颗粒运动形成的——例如浊流、底流和深海潮流。

    (b) Textures: These are very variable for all three facies types. Single observations of textural parameters (mean size, sorting and skewness, etc.) are not, therefore, adequate. Multiple analyses are required. Good progress is being made in characterising different facies types through bi-variate cross plots of textural attributes-e.g., mean-size versus sorting, sorting versus skewness, the coarsest one-percentile © versus median (M) (CM plots) [105,149]. Distinguishing between facies in this way seems to be better for silt to medium sand grades, but is more equivocal for both finer and coarser grain sizes.
    (b) 纹理:这三种相类型的纹理变化都非常大。因此,单次观察纹理参数(平均粒径、分选和偏度等)是不够的。需要多次分析。通过纹理属性的双变量交叉图(例如平均粒径与分选、分选与偏度、最粗 1 百分位(C)与中位数(M)(CM 图)[105,149])对不同相类型进行表征,已取得良好进展。以这种方式区分相类型似乎对粉砂到中砂级别效果较好,但对更细或更粗粒径则较为模糊。

    © Grading: This is an important distinguishing feature, where present. Many turbidites show normal grading or graded laminated beds but others do not. In ancient turbidites in particular, the sand and mud divisions of single beds have a sharp grain-size break rather than a gradational contact. Many contourites show bi-gradational sequences (i.e., reverse to normal grading), but others, especially many sandy contourites, do not. Hemipelagites show no systematic grading.
    © 分级:这是一个重要的区分特征(如果存在的话)。许多浊积岩显示正常分级或分级层理床,但其他则没有。尤其是在古老的浊积岩中,单层床的砂和泥部分之间存在明显的粒度断层,而非渐变接触。许多轮廓沉积物显示双重分级序列(即逆向到正常分级),但其他,特别是许多砂质轮廓沉积物,则没有。半盆地沉积物则不显示系统性的分级。

    (d) Composition: There are no easy general rules for distinguishing facies on the basis of composition alone. This depends principally on the nature of the source and supply of material, which can vary widely within and between the different facies. Where there are marked differences in composition between beds or facies within a single succession, this then should be investigated in terms of potentially different processes and supply routes.
    (d) 组成:仅凭组成来区分相位没有简单的通用规则。这主要取决于物质的来源和供应性质,而这些在不同相位内及相位之间可能有很大差异。如果在单一地层序列中不同层或相位之间存在显著的组成差异,则应从潜在的不同过程和供应路径角度进行研究。

    (e) Bioturbation and trace fossils: Turbidites generally show intermittent episodes of bioturbation in between events; the bioturbation penetrates from the top of a turbidite bed downwards. Contourites (especially finer-grained facies) show persistent and pervasive bioturbation throughout more or less continuous sedimentation; there may be omission surfaces and/or a more restricted ichnofacies. Sandy contourites (especially coarser-grained ones) show less bioturbation. Hemipelagites generally show pervasive, tiered and diverse bioturbation and ichnofacies assemblages. Dysoxic to anoxic bottom water conditions will restrict or prevent bioturbation of all deep-water facies.
    (e) 生物扰动和遗迹化石:浊积岩通常在事件之间显示间歇性的生物扰动;生物扰动从浊积岩层的顶部向下渗透。轮廓沉积物(尤其是较细粒的相)在或多或少连续的沉积过程中表现出持续且广泛的生物扰动;可能存在省略面和/或较为受限的遗迹相。砂质轮廓沉积物(尤其是较粗粒的)生物扰动较少。半陆相沉积物通常表现出广泛、分层且多样的生物扰动和遗迹相组合。缺氧至无氧的底水条件会限制或阻止所有深水相的生物扰动。
  2. Are there any clear paleocurrent measurements available that indicate a predominantly alongslope or downslope flow direction? Hemipelagites show no evidence of current activity. However, it must be noted that interpretation of paleocurrent evidence is fraught with difficulties. Turbidites can show very variable patterns due to flow instability and reflection, channel meandering, flow-stripping across levees and Coriolis deflection. Sandy contourites within contourite channels are also known to show variable directions due to channel margin interference and interaction with other processes such as deep tidal currents, and with mesoscale and macroscale eddies. It is therefore essential to obtain multiple measurements rather than simply a few, and to establish general flow
    是否有明确的古流向测量数据表明流动方向主要沿坡向或下坡向?半陆相沉积物没有显示出流动活动的证据。然而,必须指出的是,古流向证据的解释存在诸多困难。浊积岩由于流动不稳定和反射、河道弯曲、流动剥离越过堤岸以及科里奥利力偏转,可能表现出非常多变的模式。轮廓流通道内的砂质轮廓流也因通道边缘干扰以及与其他过程(如深海潮流)和中尺度及大尺度涡旋的相互作用而显示出方向多变。因此,必须获得多次测量,而不仅仅是少数几次,并建立总体流动方向。

    trends. Especially where different facies are interbedded, they may show differences in dominant flow direction.
    趋势。特别是在不同相互层理的地层中,它们可能表现出主导流向的差异。
  3. Where there is a possibility of interbedded turbidite/contourite sequences, can a distinction be made between the two facies present on the basis of character, composition and/or paleocurrent evidence? Where there is a possibility of mixed hemipelagite-pelagite/contourite/turbidite sequences, is there sufficient evidence for the influence of bottom currents or turbidity currents during sedimentation? Note that interbedding of different facies types is likely to be the norm on many continental margins, meaning this facies pattern should be specifically examined.
    在可能存在浊积岩/轮廓沉积物交错层序的情况下,是否可以根据特征、成分和/或古流向证据区分这两种相?在可能存在混合半盆地沉积物-盆地沉积物/轮廓沉积物/浊积岩层序的情况下,是否有足够的证据表明沉积过程中底流或浊流的影响?请注意,不同相类型的交错层理很可能是许多大陆边缘的常态,因此应特别检查这种相模式。
  4. Can any cyclicity present be clearly related to long-term variation in bottom-current velocity or sediment supply, or to short-term terrigenous sediment input or biogenic productivity? Can the nature and duration of such cyclicity be precisely identified through biostratigraphical chronology, magnetostratigraphy, or by tuning to the astronomical time-scale?
    任何存在的周期性是否可以明确与底流速度或沉积物供应的长期变化相关,或与短期陆源沉积物输入或生物生产力相关?是否可以通过生物地层年代学、磁性地层学或天文时间尺度调谐,精确识别这种周期性的性质和持续时间?
  5. Is there sufficient combined evidence to allow a most-likely interpretation at this stage? In many cases, this will not be possible, and it is therefore important not to force an interpretation that has a high degree of uncertainty. Several options can be presented and either probability or uncertainty factors noted. Particular care must be taken for inferred reworked turbidites, for which we currently lack definitive criteria, and also for indistinct muddy contourites, which are not easily differentiated from hemipelagites.
    目前是否有足够的综合证据支持最可能的解释?在许多情况下,这是不可能的,因此重要的是不要强行给出高度不确定的解释。可以提出多种选项,并注明概率或不确定性因素。对于推断的再工作浊积岩,尤其需要特别注意,因为我们目前缺乏明确的判定标准;对于不明显的泥质等深流沉积物,也难以与半陆源沉积物区分开来。
At this stage, further observations and/or analytical work may be required as well as interrogation of the evidence from medium- and large-scale observations.
在此阶段,可能需要进一步的观察和/或分析工作,以及对中尺度和大尺度观察证据的深入探讨。

7.3.2. Medium Scale (Depositional Body, Formation or Region)
7.3.2. 中尺度(沉积体、地层或区域)

  1. Do regional trends in facies occurrence, paleocurrent directions, textures, and mineralogical or geochemical tracers exist that would support (a) a generally alongslope bottom-current origin; (b) a downslope turbidity-current supply route; or © vertical settling in the absence of current activity? This can best be interrogated on the basis of careful regional mapping in the field, data from multiple boreholes in the subsurface and high-resolution seismic data where available. Laboratory analyses from this wide dataset will need to be collated.
    是否存在沉积相分布、古流向、岩理以及矿物学或地球化学示踪剂的区域性趋势,以支持(a)一般沿坡底流的起源;(b)沿坡下的浊流供应路径;或(c)在无流体活动情况下的垂直沉降?这最好通过现场的细致区域测绘、地下多个钻孔的数据以及可获得的高分辨率地震数据来探讨。需要汇总来自这一广泛数据集的实验室分析结果。
  2. Is there any evidence of (a) bottom-current activity, such as widespread unconformities, condensed sequences, regional variation in thickness (allowing reconstruction of mound-like geometry) and drift geometry; (b) turbidity current activity, such as localised channel erosion, abundant shale clasts and associated mass-transport deposits; or © a complete absence of anything other than slow continuous and pervasive hemipelagic sedimentation? This requires a similar approach to that for (1) above. In addition, biostratigraphic data is needed, for example, from micropaleontological analyses.
    是否有(a)底流活动的证据,如广泛的不整合面、浓缩层序、厚度的区域变化(可用于重建丘状几何形态)和漂积体几何形态;(b)浊流活动的证据,如局部通道侵蚀、大量页岩碎屑及相关的质量运输沉积物;或(c)除缓慢连续且普遍的半陆相沉积外,完全没有其他沉积活动的证据?这需要采用与上述(1)类似的方法。此外,还需要生物地层学数据,例如来自微古生物学分析的数据。
  3. Is it possible to reconstruct the shape and 3D geometry of the whole sedimentary body? If so, are the elongation and propagation trends parallel or perpendicular to the inferred margin? Or is the geometry a widespread drape over underlying topography? Both surface mapping and subsurface seismic data will be required to answer these questions.
    是否有可能重建整个沉积体的形状和三维几何结构?如果可以,延伸和传播的趋势是与推断的边缘平行还是垂直?还是几何形态是覆盖在下伏地形上的广泛披覆?要回答这些问题,需要同时利用地表测绘和地下地震数据。
  4. Are the associated facies, paleontological data and rates of accumulation compatible with a deep-water depositional setting interpretation? It is important to interrogate and confirm the depositional setting and to consider facies associations and medium-scale vertical sequences of facies or bed thicknesses. Even where it is difficult to gather evidence from putative turbidites or contourites, it may be easier to observe that the interbedded associated facies are dominantly of deep-water pelagic and hemipelagic type. Vertical trends of turbidite bed thickness have been extensively studied and documented, so that thinning-up, thickening-up, and compensation cycles can be recognised. Regular cyclicity with orbital periodicity is well known for hemipelagite-pelagite successions. Work is currently ongoing with regard to bed thickness and cyclicity variation in contourites, but the need for precise chronology is paramount.
    相关的相、古生物学数据和沉积速率是否与深水沉积环境的解释相符?重要的是要质疑并确认沉积环境,同时考虑相组合和中尺度的相垂直序列或层厚度。即使难以从推测的浊积岩或轮廓沉积物中收集证据,也可能更容易观察到夹层的相关相主要是深水远洋和半远洋类型。浊积岩层厚的垂直变化趋势已被广泛研究和记录,因此可以识别出向上变薄、向上变厚和补偿循环。半远洋-远洋沉积物序列的规则周期性与轨道周期性密切相关。目前关于轮廓沉积物的层厚和周期性变化的研究正在进行中,但精确年代学的需求至关重要。
  5. Is there any seismic evidence for depositional setting and style? Consider, in particular, the small- and medium-scale seismic criteria listed by [ 141 , 148 ] [ 141 , 148 ] [141,148][141,148], such as seismic facies, architectural
    是否有任何地震证据支持沉积环境和沉积方式?特别考虑 [ 141 , 148 ] [ 141 , 148 ] [141,148][141,148] 列出的中小尺度地震标准,如地震相、构造

    elements and progradational/aggradational patterns. However, it is important to note that features such as giant sediment waves ( 1 3 km 1 3 km 1-3km1-3 \mathrm{~km} wavelength) (typical as a recognised seismic facies) may be formed as the result of both bottom current and turbidity current activity [150]. Their link to downslope creep processes (perhaps of hemipelagic sediments) is less well established.
    元素和前进/堆积模式。然而,重要的是要注意,诸如巨型沉积波( 1 3 km 1 3 km 1-3km1-3 \mathrm{~km} 波长)(作为公认的地震相典型特征)等特征,可能是由底流和浊流活动共同形成的[150]。它们与下坡蠕变过程(可能是半盆地沉积物)的联系尚未得到充分证实。

7.3.3. Large Scale (System, Ocean or Continent)
7.3.3. 大尺度(系统、海洋或大陆)

  1. Do the conclusions from Stages 1 and 2 above fit with what is known from other independent lines of evidence concerning major oceanographic or paleoceanographic features and continental reconstructions? Are bottom currents or turbidity currents to be expected in the depositional setting reconstructed, and are interbedded facies to be expected?
    上述第 1 阶段和第 2 阶段的结论是否与其他独立证据线所知的主要海洋学或古海洋学特征及大陆重建相符?在重建的沉积环境中,是否应预期存在底流或浊流?是否应预期存在夹层相?
  2. What kind of bottom-current systems might have existed in the study area at the time of deposition, taking into account constraints imposed by known paleoclimatic conditions and inferred basin location and geometry?
    考虑到已知的古气候条件和推断的盆地位置及几何形态限制,沉积时研究区可能存在何种类型的底流系统?
  3. Was there an obvious sediment source and downslope supply route for turbidity currents?
    是否存在明显的沉积物来源和向下坡供应的浊流路径?
  4. Is there any independent seismic evidence for the oceanographic setting, shelf-slope geometry and potential water depth at the time of deposition? Consider, in particular, the large- and medium-scale seismic criteria listed by [114].
    是否有任何独立的地震证据支持沉积时的海洋环境、大陆架-坡地形及潜在水深?特别考虑[114]列出的大尺度和中尺度地震标准。

8. Conclusions  8. 结论

Significant progress has been made in the last two decades in distinguishing between turbidites, contourites and hemipelagites in modern and ancient deep-water systems. However, there is still much controversy surrounding classification, especially where the interpretation of ancient series is concerned. There are four main reasons for this: (1) the transport-depositional processes show a degree of overlap as part of a continuum, meaning the deposit characteristics also overlap; (2) the three facies commonly occur interbedded within continental margin deposits, meaning interpretation based on occurrence is not always possible; (3) there are many published examples of speculative interpretations of ancient sediments where the evidence is limited (e.g., sedimentary structures alone) and the conclusions erroneous; and (4) several sets of conflicting criteria for facies interpretation exist in the literature, especially for contourites but also for sandy turbidites and debrites.
在过去二十年中,在区分现代和古代深水系统中的浊积岩、轮廓沉积物和半盆地沉积物方面取得了显著进展。然而,关于分类仍存在许多争议,尤其是在古代地层的解释方面。造成这种情况的主要有四个原因:(1)运输-沉积过程表现出一定程度的重叠,作为一个连续体的一部分,导致沉积物特征也存在重叠;(2)这三种相常常交错出现在大陆边缘沉积物中,因此仅凭出现情况进行解释并不总是可行;(3)文献中存在许多对古代沉积物的推测性解释,证据有限(例如,仅凭沉积结构),且结论错误;(4)文献中存在多套相互矛盾的相解释标准,尤其是针对轮廓沉积物,也包括砂质浊积岩和碎屑岩。
There is good agreement now on the nature of the end-member processes and their physical parameters.
目前对于端元过程的性质及其物理参数已有较好的一致意见。
  • Turbidity currents are episodic short-duration events (lasting hours to days) which show wide variation in flow size, speed and concentration. They are turbulent suspensions of mud and sand in water which are propelled downslope by gravity acting on the excess density. They can develop internal segregation in terms of process and sediment concentration, as well as downslope flow transformation.
    浊流是短暂的间歇性事件(持续数小时到数天),其流量大小、速度和浓度变化范围广泛。它们是在水中悬浮的泥沙混合物,由于密度过剩而受重力驱动沿坡面下滑。浊流内部可以在过程和沉积物浓度方面形成分层,并且沿坡面流动会发生转变。
  • Bottom currents are semi-continuous long-duration processes (lasting thousands to millions of years) which are generally low-concentration and which have a relatively low flow speed. They can be driven by surface winds, thermohaline circulation and tides. They are affected by intermittent eddies, benthic storms, flow cascading and tsunamis.
    底流是半连续的长时间过程(持续数千年至数百万年),通常浓度较低,流速相对较慢。它们可以由表面风、热盐环流和潮汐驱动。底流受间歇性涡流、底层风暴、流动级联和海啸的影响。
  • Hemipelagic deposition is a continuous process through geological time, involving both vertical settling and slow lateral advection through the water column. Together with pelagic settling, these are ‘background’ processes which are only evident in the absence of either turbidity currents or bottom currents.
    半盆地沉积是一个贯穿地质时间的连续过程,涉及垂直沉降和通过水柱的缓慢横向输送。与远洋沉降一起,这些是“背景”过程,仅在没有浊流或底流的情况下才明显。
These end-member processes lead to deposits that are characterised by specific sedimentary features, including sedimentary structures, facies sequences, ichnofacies, sediment textures, composition and microfabric. These characteristics are best summarised in terms of standard facies models or sequences and the variations from these models that are typically encountered in natural
这些端元过程形成的沉积物具有特定的沉积特征,包括沉积结构、相序列、生痕相、沉积物质地、成分和微构造。这些特征最好通过标准相模型或相序列及其在自然系统中常见的变异来总结。

systems. We have synthesised data on the principal facies models and illustrated each type with photographs of modern and ancient examples from well-established systems.
我们综合了主要相模型的数据,并通过现代和古代典型系统的照片对每种类型进行了说明。
  • Turbidites, including coarse-, medium-, and fine-grained turbidites, characterised by the Lowe, Bouma and Stow sequences respectively. We note that it is not always possible to distinguish between facies at the fine end of the spectrum, i.e., muddy turbidites, contourites and hemipelagites. Equally, some of the sand-only turbidites and contourites may show very similar features.
    浊积岩,包括粗粒、中粒和细粒浊积岩,分别以 Lowe、Bouma 和 Stow 序列为特征。我们注意到,在细粒端的相之间(即泥质浊积岩、轮廓流沉积物和半盆地沉积物)并不总是能够区分。同样,一些仅含砂的浊积岩和轮廓流沉积物可能表现出非常相似的特征。
  • Contourites, including bi-gradational mud-sand and sandy contourite facies models. The bi-gradational sequence (C1-C5) is well established, whereas the sandy contourite models are relatively new. Contourites are much less well known than turbidites from ancient series on land or in the subsurface. This is an important area for future research.
    等深流沉积物,包括双渐变泥-砂和砂质等深流相模型。双渐变序列(C1-C5)已被充分确立,而砂质等深流模型则相对较新。与陆地或地下古老地层中的浊积岩相比,等深流沉积物的认识要少得多。这是未来研究的重要领域。
  • Hemipelagites have a simple cyclic facies model, showing compositional and colour variation. There is a wide range of types depending on dominant sediment supply, i.e., biogenic, terrigenous, volcaniclastic and glacigenic. Organic-rich black-shale hemipelagites have different and specific characteristics.
    半盆地沉积物具有简单的循环相模型,显示出成分和颜色的变化。根据主导沉积物供应的不同,即生物源、陆源、火山碎屑和冰川源,存在多种类型。富有机质的黑色页岩半盆地沉积物具有不同且特定的特征。
It must be recognised that clear distinction is not always possible on the basis of sedimentary characteristics alone, and that uncertainties should be highlighted in any interpretation. It is far better to declare a lack of sufficient evidence than to make a speculative interpretation that may be misleading to subsequent workers. Wherever possible, a three-scale approach to distinction for all deep-water facies types should be attempted, including large-scale (oceanographic and tectonic setting), regional-scale (architecture and association), and small-scale (sediment facies) observations. It is only by using this rigorous scientific method that a valid outcome can be achieved.
必须认识到,仅凭沉积特征并不总能明确区分,应在任何解释中突出不确定性。与其做出可能误导后续研究者的推测性解释,不如坦率承认证据不足。在可能的情况下,应尝试对所有深水相类型采用三尺度区分方法,包括大尺度(海洋学和构造环境)、区域尺度(构造和组合)以及小尺度(沉积相)观察。只有通过这种严谨的科学方法,才能获得有效的结果。
The authors are aware of further work that is currently in progress on microfacies characterisation of deep-water carbonates, microfabric discrimination of fine-grained clastic facies, textural discrimination of turbidites and contourites and the distinctive nature of facies cyclicity and meso-scale sequences (5-50 m ). All of these approaches are expected to yield important data and results for this ongoing debate. Future approaches to the deep-water sedimentary systems that we believe will be especially significant include (a) direct long-term seafloor observations, measurement and sampling; (b) establishing a sound evidential link between the process of deposition and nature of the deposit; © resolving the nature and effects of process interaction; and (d) working towards a clearer understanding of the broader societal impact of our deep-sea research. Finally, we should always read published work (including this paper) with a critical mind.
作者们了解到,目前正在进行关于深水碳酸盐岩微相特征、细粒碎屑岩微构造区分、浊积岩与轮积岩的纹理区分以及相循环性和中尺度序列(5-50 米)独特性质的进一步研究。所有这些方法预计将为这一持续的争论提供重要的数据和结果。我们认为,未来对深水沉积系统特别重要的研究方法包括:(a)直接的长期海底观测、测量和采样;(b)建立沉积过程与沉积物性质之间的可靠证据联系;(c)解决过程相互作用的性质及其影响;(d)努力更清晰地理解我们深海研究对更广泛社会的影响。最后,我们应始终以批判的眼光阅读已发表的研究成果(包括本文)。
Author Contributions: This paper is a wide-ranging review compilation. It is based on many years of work by D.S., and, more recently, by Z.S. on the topic of contourites. The original draft was written by D.S. and then modified after discussion with Z.S. The figures have been jointly compiled and drafted. All authors have read and agreed to the published version of the manuscript.
作者贡献:本文是一篇广泛的综述汇编。它基于 D.S.多年的工作,以及最近 Z.S.在等深流沉积物主题上的研究。原始稿件由 D.S.撰写,随后在与 Z.S.讨论后进行了修改。图表由双方共同编制和绘制。所有作者均已阅读并同意发表的稿件版本。

Funding: The compilation of this review paper received no specific external funding. However, the data and ideas were collected over many years and were the result of a wide range of funding.
资金来源:本综述论文的汇编未获得特定的外部资金支持。然而,数据和观点是在多年积累的基础上收集的,得益于多种资金来源的支持。

Acknowledgments: Huge thanks are due, in particular, to the very many students and colleagues who have contributed to our deep-water research efforts over the years, on land, at sea and in subsurface cores. The manuscript has benefited much from the input of several careful and detailed reviewers.
致谢:特别感谢多年来在陆地、海上及地下岩心研究中,为我们的深水研究工作做出贡献的众多学生和同事。多位细致入微的审稿人对稿件的完善也提供了极大帮助。

Conflicts of Interest: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the results.
利益冲突:作者声明不存在利益冲突。资助方未参与研究设计、数据收集、分析或解释,亦未参与稿件撰写或发表决定。

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