ABSTRACT

The percentage of calcium carbonate in 80 box core tops from the Louisiana shelf and slope reveals that modern/Holocene patterns of CaCO³ sedimentation are directly related to the proximity of the Mississippi delta system. The input of non-carbonate siliciclastic material from this system affects that relationship between detrital carbonate input, in situ production of biogenic carbonate, and dilution by detrital siliciclastic components. Using the modern/Holocene patterns, it is possible to understand calcium carbonate records in exploration wells and boreholes from offshore Louisiana. These records exhibit large and small scale changes in the relationship between these components during the Plio-Pleistocene. Some of these changes in carbonate content are site specific while other changes record significant lateral (east-west) shifts in major siliciclastic depocenters along the developing margin during the Plio-Pleistocene.