This project is a continuation of an earlier project that investigated the accumulation of fine-grained sediment on the continental shelf near the mouth of the Amazon River. The earliest research proved that sediment was actively accumulating, and later research identified the sedimentary processes controlling accumulation. This project will examine in detail the operation of the processes and how they affect the formation of sedimentary strata. This new research will be done as the Sedimentology and Stratigraphy portion of AmasSeds (A Multi-disciplinary Amazon Shelf Sediment Study), which is a cooperative project between US and Brazilian scientists. The project involves collaboration of Physical, Chemical, Biological and Geological Sciences. %%% The project will investigate boundary layer flow and suspended sediment dynamics in the shallow marine environment. In view of progress to date and the capabilities of the instrumentation, the next logical step is to extend the work to include wave-current interactions and the details of shelf sediment transport. The proposed objectives are divided into four major unresolved issues resulting from prior Amazon studies: (1) sediment accumulation, (2) physical reworking, (3) dispersal of river sediment, and (4) origin of fine-scale stratigraphy. The project will use the shelf tripod GEOPROBE to collect data to address these issues and also construct a suspended sediment profiling system and use a high frequency echo sounder to investigate river sediment dispersal budgets and fluid mud properties respectively. Cooperative field studies are planned for four stages of river discharge beginning in 1989.
