Paleoceanographic conditions following the earliest Pliocene flooding of the Tyrrhenian Sea

Abstract

High-resolution bio- and chemostratigraphy of an earliest Pliocene section from ODP Site 652 indicates that post-flood paleoceanographic conditions in the Tyrrhenian Sea can be sub-divided into two discrete intervals. A scenario derived from an integration of all the stratigraphic data indicates that normal paleoceanographic conditions were operating in the Tyrrhenian Sea only ~250 000yr after the cessation of Messinian evaporative conditions at the Miocene/Pliocene boundary. The post-flood interval is marked by an initial period of gradual infilling, the Sphaeroidinellopsis spp. acme interval, followed by a disintegration of oceanographic conditions and a second recovery period. A sudden influx of cold, deep Atlantic waters into the Tyrrhenian Sea, resulting from a major tectonic break in the Gibraltar sill, may have caused this catastrophic reversal in the orderly recovery of normal paleoceanographic conditions in the post-flood period. -from Authors