Abstract: Post-Paleozoic Changes in Volumes and Organic-Carbon Content of Marine Sedimentary Reservoirs
William W. Hay, John R. Southam
Present volumes of marine sedimentary reservoirs can be estimated from study of seismic records, hypsographic data, and isostatic considerations. Because of the breakup of the continents and seafloor spreading, great changes in the volumes of these reservoirs have occurred. Since the calcareous plankton became abundant 100 m.y. ago, the volume of pelagic sediment in the deep sea probably has increased from a quasi steady-state Paleozoic value of 30 million cu km to the present 150 million cu km. Subsidence of rifted continental margin shelves since the Triassic has allowed them to accumulate about 125 cu km. The continental-rise deposits probably have increased from about 50 million cu km to the present estimated volume of 250 million cu km. Because the organic-carbon content of sediments generally increases with sedimentation rate, knowledge of the accumulation history of these reservoirs is critical to understanding where significant volumes of petroleum source rock are to be found. Continental shelves appear to accumulate organic carbon earl in their subsidence history whereas most of the organic carbon in continental-rise deposits may be much younger.
AAPG Search and Discovery Article #90968©1977 AAPG-SEPM Annual Convention and Exhibition, Washington, DC