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Anoxic environments and oil source bed genesis

Abstract

The anoxic, aquatic, environment is a mass of water so depleted in oxygen that virtually all aerobic biological activity has ceased. Anoxic conditions occur where the demand for oxygen in the water column exceeds the supply. The specific cause for preferential lipid enrichment probably relates to the biochemistry of anaerobic bacterial activity. Recent evidence suggests that ancient organic-rich sediments containing hydrogen-rich kerogens (potential oil source beds) were deposited in similar anoxic environments. We propose the following classification for modern aquatic anoxic settings: (1) Large anoxic lakes - Permanent stratification promotes development of anoxic bottom water, particularly in large, deep lakes, which are not subject to seasonal overturn, e.g., Lake Tanganyika. (2) Anoxic silled basins - Landlocked silled basins with positive water balance tend to become anoxic. Typical are the Baltic and Black Seas. In arid region seas (Red and Mediterranean Seas), evaporation exceeds river inflow, causing negative water balance and well-aerated, nutrient-depleted bottom waters. (3) Anoxic layers caused by upwelling - Develop only when the oxygen supply in deep water cannot match demand by decaying organisms. Examples are the Benguela current and Peru coastal upwelling. (4) Open ocean anoxic layers - Found at intermediate depths in the northeastern Pacific and  More>>
Authors:
Demaison, G J; [1]  Moore, G T
  1. Chevron Overseas Petroleum Inc., San Francisco, CA
Publication Date:
Jan 01, 1980
Product Type:
Journal Article
Reference Number:
EDB-80-093921
Resource Relation:
Journal Name: Org. Geochem.; (United Kingdom); Journal Volume: 2:1
Subject:
02 PETROLEUM; 58 GEOSCIENCES; PETROLEUM DEPOSITS; EXPLORATION; GEOCHEMISTRY; AQUATIC ECOSYSTEMS; BALTIC SEA; BLACK SEA; ENVIRONMENT; INDIAN OCEAN; KEROGEN; LAKES; LIPIDS; OXYGEN; PACIFIC OCEAN; SEDIMENTARY BASINS; STRATIGRAPHY; UPWELLING; WATER; BITUMINOUS MATERIALS; CARBONACEOUS MATERIALS; CHEMISTRY; CRYOGENIC FLUIDS; ECOSYSTEMS; ELEMENTS; FLUIDS; GEOLOGIC DEPOSITS; GEOLOGIC STRUCTURES; GEOLOGY; HYDROGEN COMPOUNDS; NONMETALS; ORGANIC COMPOUNDS; OXYGEN COMPOUNDS; RESOURCES; SEAS; SURFACE WATERS; 020200* - Petroleum- Reserves, Geology, & Exploration; 580400 - Geochemistry- (-1989)
OSTI ID:
5325903
Country of Origin:
United Kingdom
Language:
English
Other Identifying Numbers:
Journal ID: CODEN: ORGED
Submitting Site:
TIC
Size:
Pages: 9-31
Announcement Date:
Sep 01, 1980

Citation Formats

Demaison, G J, and Moore, G T. Anoxic environments and oil source bed genesis. United Kingdom: N. p., 1980. Web. doi:10.1016/0146-6380(80)90017-0.
Demaison, G J, & Moore, G T. Anoxic environments and oil source bed genesis. United Kingdom. https://doi.org/10.1016/0146-6380(80)90017-0
Demaison, G J, and Moore, G T. 1980. "Anoxic environments and oil source bed genesis." United Kingdom. https://doi.org/10.1016/0146-6380(80)90017-0.
@misc{etde_5325903,
title = {Anoxic environments and oil source bed genesis}
author = {Demaison, G J, and Moore, G T}
abstractNote = {The anoxic, aquatic, environment is a mass of water so depleted in oxygen that virtually all aerobic biological activity has ceased. Anoxic conditions occur where the demand for oxygen in the water column exceeds the supply. The specific cause for preferential lipid enrichment probably relates to the biochemistry of anaerobic bacterial activity. Recent evidence suggests that ancient organic-rich sediments containing hydrogen-rich kerogens (potential oil source beds) were deposited in similar anoxic environments. We propose the following classification for modern aquatic anoxic settings: (1) Large anoxic lakes - Permanent stratification promotes development of anoxic bottom water, particularly in large, deep lakes, which are not subject to seasonal overturn, e.g., Lake Tanganyika. (2) Anoxic silled basins - Landlocked silled basins with positive water balance tend to become anoxic. Typical are the Baltic and Black Seas. In arid region seas (Red and Mediterranean Seas), evaporation exceeds river inflow, causing negative water balance and well-aerated, nutrient-depleted bottom waters. (3) Anoxic layers caused by upwelling - Develop only when the oxygen supply in deep water cannot match demand by decaying organisms. Examples are the Benguela current and Peru coastal upwelling. (4) Open ocean anoxic layers - Found at intermediate depths in the northeastern Pacific and northern Indian Oceans; due to distance from deep, oxygenated polar water sources. Analogous to world-wide anoxic events at times of global climatic warm-ups and major transgressions, as in late Jurassic and middle Cretaceous time. Petroleum exploration can be greatly assisted by using geochemistry to identify paleo-anoxic events in the stratigraphic record. Recognition of the proposed anoxic models in ancient sedimentary basins should help in regional mapping of oil shales and oil-source beds. 17 figures.}
doi = {10.1016/0146-6380(80)90017-0}
journal = []
volume = {2:1}
journal type = {AC}
place = {United Kingdom}
year = {1980}
month = {Jan}
}