Planktonic foraminifera and sedimentology of ODP Hole 115-708A

Pleistocene and Pliocene sediments from the top five cores of Hole 708A, western Indian Ocean, were subsampled to compare the degree of carbonate dissolution in pelagic and turbidite sediments. The extent of dissolution for each sample was established using the percent of whole planktonic tests and an index based on the dominance of planktonic genera resistant to dissolution. Most samples show evidence for dissolution; foraminifers are significantly more dissolved in pelagic sediments than turbidites. Sorting of sediment is evident in those samples where the percentages of whole juvenile tests are high, but adult tests are low.