Differentiating the Causes of Aged Organic Carbon in Marine Sediments

Abstract

Aged organic carbon (OC) is widely observed in surficial sediments deposited on continental margins, resulting from several factors including old OC input and sedimentological processes. While the supply of old OC to marine sediments has been examined and quantified in a range of continent margin settings, there have been few attempts to constrain the extent to which hydrodynamic processes, specifically lateral transport, contribute to the old age of sedimentary OC. Here, we propose a mathematical index, bAgedOC, to differentiate the causes of sedimentary aged OC, and apply this approach to two typical sediment transport pathways that follow the supply and dispersal of terrestrial OC in the marine environment, and further extrapolate it to submarine canyon, Arctic and deep-sea environments. The index, representing a modification of a widely used quantitative method, provides a novel approach to distinguish the contribution of lateral transport to the pre-depositional aging of OC in the oceanic region.