Oceanic Sediments

Abstract

The ocean basins are the ultimate sink for all the material transported by rivers or blown by winds into the sea. In addition, they produce large quantitities of autochthonous biogenic material. In their areal extent, the sediments of the present-day deep ocean basins surpass all the other sedimentary environments by far. Even measured by volume and for a certain time slice, deep-sea sediments have presumably predominated over other sediment types, for example shelf deposits, for the last millions of years. However, in the ancient record, a relatively large proportion of former deepsea sediments is missing. These materials were subducted and partially transformed into metamorphic rocks at convergent plate margins, incorporated into orogenic belts, and eroded as a result of uplift. Nevertheless, even in ancient rock sequences on the continents, nonmetamorphic deep-sea sediments play a great part, and their identification and interpretation are an important objective in basin studies and paleogeographic reconstructions.