Significance of δDkerogen, δ13Ckerogen and δ34Spyrite from several Permian/Triassic (P/Tr) sections

wFor the first time we report delta D of kerogen (delta D-kerogen) for three Permian-Triassic (P-Tr) sequences (Hovea#3, Perth Basin, Western Australia; Jameson Land, East Greenland and Lusitaniadalen, Spitsbergen). We have compared delta D-kerogen with delta C-13 of kerogen (delta D-13(kerogen)) and delta S-34 of total reduced inorganic sulfur (IRIS, essentially pyrite; delta S-34(pyrite)) of all the sections and for one sample set with delta C-13 of carbonate (delta C-13(carbonate)) to establish (i) similarities between the sections and (ii) evaluate whether these signals are local and/or global. Stable isotope shifts occur for all three sample sets either at the P-Tr transition (Western Australia) or coinciding with the marine ecosystem collapse (Spitsbergen and East Greenland). delta D-kerogen reflects organic matter (OM)/ kerogen type and is not sensitive to the low level of thermal maturation. Reliable palaeoenvironmental information in terms of the use of AD can therefore only be obtained for the P-Tr transition from hydrogen compound-specific isotope analyses (CSIA) of biomarkers (Nabbefeld et al., 2010b). The negative shifts in delta D-13(kerogen) (primary) and delta C-13(kerogen) are attributed to the release of C-13-depleted carbon into the atmosphere, whereas the isotopic excursions in delta S-34(pyrite) relate to palaeoredox changes. However, the global coincidence in timing of the shifts in delta D-kerogen, delta S-34(pyrite) and delta C-13(kerogen), suggests a relation between the sulfur, carbon and hydrogen cycles. The negative shifts in delta C-13(carbonate) (primary) are in general attributed to the release of C-13-depleted source of carbon into the oceans and atmosphere, whereas delta C-13(kerogen) can reflect the latter in certain cases, but can also be superimposed by varying sources of OM/kerogen type. Isotopic excursions in delta S-34(pyrite) relate to global changes in the palaeoredox conditions that affect sulfur cycling in the ancient seas. (C) 2010 Elsevier B.V. All rights reserved.