Organic matter sources, transport, degradation and preservation on a narrow rifted continental margin: Shoalhaven, southeast Australia

A three-component mixing model was used to show that OM in continental shelf sediments consisted of 15-20% terrigenous biospheric OM (mostly modern plants), 15-25% fossil C, and marine OM. While such bimodal terrigenous input (modern plants and fossil C) is typical of active margins, this study reinforces the paradigm that OM residence times within major bioactive reservoirs during transfer (in turn related to geomorphic characteristics) strongly influence the composition of exported OM.