The early Paleocene up to the initial establishment of stable océanographie conditions after the K/T boundary event is examined in the eastern Tethys based on stratigraphie, faunal, CaCO3, and δ18O isotope analyses. The earliest Paleocene is characterized by redeposited and bioturbated sediments containing abundant reworked Cretaceous foraminifers and nannofossils mixed in with a characteristic basal Tertiary assemblage. Widespread hiatuses are identified in this interval based on abrupt truncation of dominant species and outcrop observations: at the K/T boundary, the P0/Pla boundary, and at the P l a / P lb boundary. Species diversity increases rapidly above this interval. These faunal changes are accompanied by decreasing CaCO3 accumulation interrupted by three major negative excursions: at the K/T boundary, in Subzone Plb, and at the Plb/Plc boundary coincident with deposition of a black organic-rich clay layer and the decline and eventual extinction of the dominant Cretaceous survivor Guembelitria. Stable-carbonate deposition began in foraminiferal Subzone Pic and the nannofossil NP1/NP2 Zone boundary about 400,000 years after the K/T boundary event, correlative with initial stabilization of foraminiferal assemblages as indicated by relatively stable species populations.
|Number of pages||10|
|Journal||Special Paper of the Geological Society of America|
|State||Published - 1 Jan 1990|