South Atlantic organic-rich sediments

facies, processes and environments of deposition

Research output: Contribution to journalArticle

Abstract

Organic-rich sediments (black shales) occur in parts of the South Atlantic ocean within Jurassic, Cretaceous and Neogene sections. These black shales are represented by various lithologies, including mudstones, marlstones, limestones, sandstones, pebbly mudstones and diatomites. They range from thin to very thick bedded, laminated, fissile or structureless, and show varying degrees and types of bioturbation. Texturally and compositionally they are equally varied. Organic carbon may be of principally marine or terrigenous source and forms from 1% to over 20% of the sediment. In many cases, the black shales are interbedded with organic-poor lithologies in cycles with irregular periodicities that average 20,000 to 140,000 years. The range of depositional processes of these black shales includes sliding, debris flows, high- and low-concentration turbidity currents, pelagic/hemipelagic sedimentation, and winnowing by shelf bottom currents. They occur in various palaeogeographical settings from nearshore shelf to ocean basin, and have been differently influenced by variations in bottom water oxygenation, organic matter supply and rates of sedimentation.
Original languageEnglish
Pages (from-to)287-299
Number of pages13
JournalGeological Society Special Publications
Volume26
DOIs
Publication statusPublished - 1987

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mudstone
lithology
sedimentation
diatomite
bottom current
oxygenation
turbidity current
marl
bioturbation
ocean basin
debris flow
bottom water
sediment
periodicity
Neogene
sliding
Jurassic
organic carbon
limestone
sandstone

Cite this

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title = "South Atlantic organic-rich sediments: facies, processes and environments of deposition",
abstract = "Organic-rich sediments (black shales) occur in parts of the South Atlantic ocean within Jurassic, Cretaceous and Neogene sections. These black shales are represented by various lithologies, including mudstones, marlstones, limestones, sandstones, pebbly mudstones and diatomites. They range from thin to very thick bedded, laminated, fissile or structureless, and show varying degrees and types of bioturbation. Texturally and compositionally they are equally varied. Organic carbon may be of principally marine or terrigenous source and forms from 1{\%} to over 20{\%} of the sediment. In many cases, the black shales are interbedded with organic-poor lithologies in cycles with irregular periodicities that average 20,000 to 140,000 years. The range of depositional processes of these black shales includes sliding, debris flows, high- and low-concentration turbidity currents, pelagic/hemipelagic sedimentation, and winnowing by shelf bottom currents. They occur in various palaeogeographical settings from nearshore shelf to ocean basin, and have been differently influenced by variations in bottom water oxygenation, organic matter supply and rates of sedimentation.",
author = "Stow, {D. A. V.}",
year = "1987",
doi = "10.1144/GSL.SP.1987.026.01.20",
language = "English",
volume = "26",
pages = "287--299",
journal = "Geological Society Special Publications",
issn = "0305-8719",
publisher = "Geological Society of London",

}

TY - JOUR

T1 - South Atlantic organic-rich sediments

T2 - facies, processes and environments of deposition

AU - Stow, D. A. V.

PY - 1987

Y1 - 1987

N2 - Organic-rich sediments (black shales) occur in parts of the South Atlantic ocean within Jurassic, Cretaceous and Neogene sections. These black shales are represented by various lithologies, including mudstones, marlstones, limestones, sandstones, pebbly mudstones and diatomites. They range from thin to very thick bedded, laminated, fissile or structureless, and show varying degrees and types of bioturbation. Texturally and compositionally they are equally varied. Organic carbon may be of principally marine or terrigenous source and forms from 1% to over 20% of the sediment. In many cases, the black shales are interbedded with organic-poor lithologies in cycles with irregular periodicities that average 20,000 to 140,000 years. The range of depositional processes of these black shales includes sliding, debris flows, high- and low-concentration turbidity currents, pelagic/hemipelagic sedimentation, and winnowing by shelf bottom currents. They occur in various palaeogeographical settings from nearshore shelf to ocean basin, and have been differently influenced by variations in bottom water oxygenation, organic matter supply and rates of sedimentation.

AB - Organic-rich sediments (black shales) occur in parts of the South Atlantic ocean within Jurassic, Cretaceous and Neogene sections. These black shales are represented by various lithologies, including mudstones, marlstones, limestones, sandstones, pebbly mudstones and diatomites. They range from thin to very thick bedded, laminated, fissile or structureless, and show varying degrees and types of bioturbation. Texturally and compositionally they are equally varied. Organic carbon may be of principally marine or terrigenous source and forms from 1% to over 20% of the sediment. In many cases, the black shales are interbedded with organic-poor lithologies in cycles with irregular periodicities that average 20,000 to 140,000 years. The range of depositional processes of these black shales includes sliding, debris flows, high- and low-concentration turbidity currents, pelagic/hemipelagic sedimentation, and winnowing by shelf bottom currents. They occur in various palaeogeographical settings from nearshore shelf to ocean basin, and have been differently influenced by variations in bottom water oxygenation, organic matter supply and rates of sedimentation.

U2 - 10.1144/GSL.SP.1987.026.01.20

DO - 10.1144/GSL.SP.1987.026.01.20

M3 - Article

VL - 26

SP - 287

EP - 299

JO - Geological Society Special Publications

JF - Geological Society Special Publications

SN - 0305-8719

ER -