Quantitative Characterization of Terrestrially-derived Organic Matter in Recent and Ancient Marine Sediments Specific Objectives of this research are: (i) To improve and expand methods to recognize and characterize terrestrial (and marine) sedimentary organic matter, with special emphasis placed upon macromolecular components; (ii) to develop and refine mixing models, based on mass balance calculations using coupled concentration-isotope composition measurements on discrete components, which more accurately describe the contributions from river systems to shelf or basin sediments and to delineate these contributions as a function of distance from source. The approach builds upon previous studies. A detailed comparison of two established methods for characterizing OC, namely CuO oxidation and analytical pyrolysis will be performed. A side-by-side quantitative evaluation of the scope and limitations will provide useful quantitative geochemical information including a mass balance of the major constituents with respect to TOC for selected "end-member" samples. This task will be facilitated by bulk and compound specific isotopic measurements on representative components. This information will then be collated and will form the basis for mixing models developed to describe contributions from terrestrial (and marine) sources to sedimentary OC. The validity of these models will be appraised in investigations of sedimentary environments for which abundant supplementary geochemical information exists (Gulf of Mexico, Washington margin). Subsequently the models will be applied to key environments in which present understanding of terrestrial organic matter influences is more limited (Black Sea, Amazon shelf).
