The proposed research will identify patterns, processes and controls of deep-water carbonate sedimentation in the Lesser Antilles arc. The study will be based on analysis of Holocene to late Pleistocene sediments in existing piston and gravity cores. The following questions will be addressed: 1. what are the sources and transport mechanisms of deep-water carbonate sediments in the arc?, 2. do the deep-water sediments record cyclic variations in carbonate content, carbonate mineralogy, and frequency of turbidites that correspond to sea level fluctuations?, and 3. how is carbonate sedimentation affected by arc volcanism and input of terrigenous detritus form South American sources? A stratigraphic framework for the cores will be developed using foraminiferal biostratigraphy, tephrochronology, and oxygen isotope stratigraphy. Detailed core descriptions, total carbonate analyses, thin section petrography, scanning electron microscopy, x-ray diffraction, and strontium determinations will establish the distribution of carbonate, the relative contributions of pelagic and neritic carbonate components, and the proportions of volcanic and terrigenous detritus. The study represents the first in-depth analysis of modern deep-water carbonate sediments in a convergent margin. It will complement previous studies of volcanogenic and terrigenous sediments in the Lesser Antilles to show how deep-water deposition in a volcanic arc compares with periplatform sedimentation in passive margin settings. The findings will aid interpretation of other volcanic arc sequences, both modern ancient.
