Each year the Amazon River delivers approximately 1 billion metric tons of sediment to the equatorial Atlantic (Meade et al., 1985). A portion of this debris is highly weathered and contains abundant reactive Fe, Mn, AI, and Si oxides. The associated terrestrial organic matter is biologically refractory (Hedges et al., 1986). Upon entering the Amazon Shelf region, particles are exposed to seawater brine, mixed with labile planktonic organic matter, and incorporated into the seabed where a variety of geochemical reactions take place. Major research efforts within the AmasSeds Project include elucidating the types and rates of these diagenetic reactions (particularly those associated with the decomposition of organic matter), their governing factors, and their influence on the properties of overlying water and preserved deposits.