Premium
Carbon‐sulphur‐iron‐variations and sulphur isotope patterns of Silurian Graptolite Shales
Author(s) -
DILL H.,
NIELSEN H.
Publication year - 1986
Publication title -
sedimentology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.494
H-Index - 108
eISSN - 1365-3091
pISSN - 0037-0746
DOI - 10.1111/j.1365-3091.1986.tb01973.x
Subject(s) - geology , diagenesis , oil shale , sedimentary depositional environment , devonian , sulfur , anoxic waters , isotopes of carbon , total organic carbon , geochemistry , paleozoic , carbon fibers , paleontology , mineralogy , environmental chemistry , chemistry , oceanography , materials science , organic chemistry , structural basin , composite number , composite material
Black shale horizons (Graptolithenschiefer) in Silurian and Lower Devonian strata of the Franconian‐Thuringian Highlands (Frankenwald‐Thüringer Wald) of Germany have high metal concentrations (e.g. U,V,Mo). Organic carbon, sulphur and iron contents, degree of pyritization (DOP) and sulphur isotope ratios from the Lower Graptolite Shales, along with faunal and sedimentological evidence show that the depositional environment was anoxic. Although some data (e.g. C/S plots) do not suggest completely euxinic conditions, the DOP versus C plot indicates a Black Sea‐type environment. From the sulphur isotope data the environment fluctuated between‘open’and‘closed’with respect to sulphate supply, with higher carbon contents reflecting an increased bacterial reduction of the available sulphate. Diagenetic effects were responsible for somewhat unusual plots of C/S ratios, though iron availability may have been influential.