Secular and environmental constraints on the occurrence of dinosterane in sediments

Journal Article · Mon Jun 01 00:00:00 EDT 1992 · Geochimica et Cosmochimica Acta; (United States)

DOI:https://doi.org/10.1016/0016-7037(92)90200-3· OSTI ID:5058381

Summons, R E; Boreham, C J ^[1]; Thomas, J ^[2]; Maxwell, J R ^[3]

---

1. Bureau of Mineral Resources, Geology and Geophysics, Canberra City (Australia)
2. WS Atkins Engineering Sciences, Epsom (United Kingdom)
3. Univ. of Bristol (United Kingdom)

The distribution patterns of sedimentary A-ring methylated steranes have changed markedly over geological time. Although dinosterane and its isomer 24-ethyl-4{alpha}-methylcholestane have been tentatively identified in three Proterozoic rock units, they are either not detectable or occur in low abundance relative to 3-methyl steranes throughout most of the Palaeozoic. Between Permian and middle Triassic times (260-220 Ma ago), 4-methyl sterane abundances in marine sediments increased markedly. The presence of dinosterane in some middle Triassic marine sediments is contemporaneous with the appearance of fossil cysts of uncontested dinoflagellate affinity. 4-Methyl steranes, including dinosterane or their precursor sterenes and sterols, then show a continuous presence, often in high abundance, in marine sediments from the late Triassic through to the present day. Assemblages of 4-methyl steranes and their precursors, but with dinosterane absent or in low relative abundance, are often the predominant steroids in lacustrine sediments in the Cainozoic. Dinosterane appears to arise predominantly from marine dinoflagellates and, as a consequence, is a useful biological marker for Mesozoic and Cainozoic marine organic matter. The isomer 24-ethyl-4{alpha}-methylcholestane is likely to have multiple origins although its very high abundance in Tertiary lacustrine sediments and oils, compared to older materials, suggests that dinoflagellates could also be the source in these cases.

• OSTI ID: 5058381
• Journal Information: Geochimica et Cosmochimica Acta; (United States), Vol. 56:6; ISSN 0016-7037
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
58 GEOSCIENCES
BIOLOGICAL MARKERS
ORIGIN
ABUNDANCE
AUSTRALIA
BRAZIL
CHINA
DINOFLAGELLATE
DISTRIBUTION
EXPERIMENTAL DATA
FEDERAL REPUBLIC OF GERMANY
FOSSILS
GAS CHROMATOGRAPHY
HYDROCARBONS
MASS SPECTROSCOPY
MOLECULAR STRUCTURE
PALEOZOIC ERA
PERMIAN PERIOD
PRECAMBRIAN ERA
SAMPLING
SEDIMENTARY BASINS
SEDIMENTS
STRATIGRAPHY
SWITZERLAND
TRIASSIC PERIOD
UNITED KINGDOM
USA
ANIMALS
ASIA
AUSTRALASIA
CHROMATOGRAPHY
DATA
DEVELOPED COUNTRIES
DEVELOPING COUNTRIES
EUROPE
GEOLOGIC AGES
GEOLOGIC STRUCTURES
GEOLOGY
INFORMATION
INVERTEBRATES
LATIN AMERICA
MASTIGOPHORA
MESOZOIC ERA
MICROORGANISMS
NORTH AMERICA
NUMERICAL DATA
ORGANIC COMPOUNDS
PROTOZOA
SEPARATION PROCESSES
SOUTH AMERICA
SPECTROSCOPY
020200* - Petroleum- Reserves
Geology
& Exploration
580000 - Geosciences