Normal paraffins in shales as an indicator of depositional environment

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doi: 10.1016/S0016-7037(97)00238-X
Author(s): Yamamoto, Koshi; Okada, Takashi; Takayanagi, Yukio; Mimura, Koichi
Author Affiliation(s): Primary:
Nagoya University, Department of Earth and Planetary Sciences, Nagoya, Japan
Shin-Nippon Meteorological and Oceanographical Consultants, Osaka, Japan
Volume Title: Geochimica et Cosmochimica Acta
Source: Geochimica et Cosmochimica Acta, 61(20), p.4403-4410. Publisher: Pergamon, Oxford, International. ISSN: 0016-7037 CODEN: GCACAK
Note: In English. 22 refs.; illus., incl. sketch map
Summary: Analyses are presented of 15 shale partings from 10-61 m above a basal basalt overlain by bedded chert of Jurassic-Cretaceous age, Franciscan terrain, W North America. The basalt hydrothermally affected the overlying chert sequence up to ∼ 60 m above the basalt contact. Analyses are also presented of marine sediments cored in the NW Pacific during DSDP Leg 32, Site 305, and coastal sediments dredged off Shikoku, SW Japan. The composition of the n-paraffins in the last-named samples differ from those of the pelagic, Site 305 sediments, the coastal sediments containing abundant n-paraffins with C numbers 14-38 (maximum n-C31), indicating contributions of land plant materials. At site 305 n-paraffins are low in concentration and are mainly n-C14 to n-C21, due to marine organisms. New potential discriminant diagrams are presented for depositional environments based on the n-paraffins and isoprenoids in sediments. In the Franciscan samples, shales from the upper horizon have n-paraffins resembling those of the coastal sediments, while those of the lower horizon resemble those of the marine pelagic samples. The n-paraffin compositions of the Jurassic-Cretaceous samples have been well preserved from deposition and such compositions may evaluate depositional environments of ancient sedimentary rocks.
Year of Publication: 1997
Research Program: DSDP Deep Sea Drilling Project
Key Words: 02 Geochemistry; 06 Petrology, Sedimentary; Aliphatic hydrocarbons; Alkanes; Asia; Bedding; California; Cenozoic; Chemically precipitated rocks; Chert; Clastic rocks; Coastal environment; DSDP Site 305; Deep Sea Drilling Project; Depositional environment; Far East; Franciscan Complex; Geochemical indicators; Geochemistry; Holocene; Hydrocarbons; Japan; Kochi Japan; Leg 32; Marin County California; Marine environment; Marine sediments; Mesozoic; N-alkanes; North Pacific; Northwest Pacific; Organic compounds; Pacific Ocean; Paraffins; Pelagic environment; Planar bedding structures; Quaternary; Sedimentary rocks; Sedimentary structures; Sediments; Shale; Shikoku; United States; West Pacific
Coordinates: N331200 N335200 E1343900 E1323900
N320007 N320008 E1575101 E1575059
N374800 N382000 W1223000 W1230000
Record ID: 1998017604
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom