Clarification of C-S relationships of marine black shales using stable isotopic composition of reduced sulfur

Conference · Wed Jan 01 04:00:00 EST 1992 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:6035393

Zaback, D A; Pratt, L M ^[1]

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1. Indiana Univ., Bloomington, IN (United States). Dept. of Geological Sciences

Carbon-sulfur relationships are compared for the Miocene Monterey Formation (Santa Maria Basin, California) and the Upper Devonian New Albany Shale (Illinois Basin, Indiana). In both formations, C-S concentrations covary for samples with the lower to more intermediate organic carbon concentrations and become invariant at higher organic carbon concentrations. While the similarity of these relationships in Monterey and New Albany suggest sulfur diagenesis occurred in similar depositional environments, sulfur isotopic data clearly indicate differences in the depositional environments. In the Monterey, the most organic-rich laminated shales are characterized by isotopic enrichment of reduced S and low S ratios and indicate that sulfate reduction occurred under sulfate-limited conditions within the sediments. In the New Albany, organic-rich laminated shales exhibit isotopic depletion of reduced S coupled with low S[sub reduced]/C[sub org] and suggest sulfur diagenesis occurred under euxinic conditions. These data show that in the absence of sulfur isotopic data, misleading conclusions concerning depositional environments can be made when using C-S plots and the traditional interpretations that are associated with these types of plots.

• OSTI ID: 6035393
• Report Number(s): CONF-921058--
• Conference Information: Journal Name: Geological Society of America, Abstracts with Programs; (United States) Journal Volume: 24:7
• Country of Publication: United States
• Language: English

Related Subjects

04 OIL SHALES AND TAR SANDS
040200* -- Oil Shales & Tar Sands-- Reserves
Geology
& Exploration
040500 -- Oil Shales & Tar Sands-- Properties & Composition
BLACK SHALES
CALIFORNIA
CHEMISTRY
COMPARATIVE EVALUATIONS
DEPOSITION
DEVELOPED COUNTRIES
DIAGENESIS
EVALUATION
GEOCHEMISTRY
GEOLOGIC DEPOSITS
GEOLOGIC HISTORY
INDIANA
ISOTOPE RATIO
MINERAL RESOURCES
NORTH AMERICA
OIL SHALE DEPOSITS
RESOURCES
ROCKS
SEDIMENTARY ROCKS
SHALES
SULFUR CONTENT
USA