Origin and distribution of terrestrial organic matter in the NW Mediterranean (Gulf of Lions): Exploring the newly developed BIT index

摘要: The Branched and Isoprenoid Tetraether (BIT) index is based on the relative abundance of nonisoprenoidal glycerol dialkyl tetraethers (GDGTs) derived from organisms living in terrestrial environments versus a structurally related isoprenoid GDGT ‘‘crenarchaeol’’ produced by marine Crenarchaeota. BIT varies between 0 1, representing marine terrestrial organic matter (OM) end-members, respectively (Hopmans et al., Earth Planet. Sci. Lett., 224, 107–116, 2004). In this study, applicability of to trace OM tested combination with other organic parameters (TOC, C/N ratio, δ13Corg, total lipid, n-alkane) Gulf Lions, river-dominated continental margin western Mediterranean. We analyzed variety soils riverbed sediments from continent as well surface sediments shelf canyons. and riverbed shows high values (>0.9), while it 0.02 0.83 sediments, decreasing seaward inner slope. For sediments, are associated lower δ13Corg higher TOC contents n-alkane concentrations. Our results confirm that can be applied coastal environments order to characterize proposed Hopmans al. (2004). Therefore useful addition proxies presently available for studying origin distribution continental margins especially valuable multiproxy studies.