The early Paleocene up to the initial establishment of stable oceanographie conditions after the K/T boundary event is examined in the eastern Tethys based on stratigraphie, faunal, CaCO ₃, and δ ¹⁸O 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/P1a boundary, and at the Pla/Plb boundary. Species diversity increases rapidly above this interval. These faunal changes are accompanied by decreasing CaCO ₃accumulation interrupted by three major negative excursions: at the K/T boundary, in Subzone P1b, and at the P1b/P1c 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 P1c 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.