1. SEDIMENTOLOGICAL AND STABLE ISOTOPE CHANGES AT THE MESSINIAN/PLIOCENE BOUNDARY IN THE EASTERN MEDITERRANEAN (HOLES 968A, 969A, AND 969B) ¹

Catherine Pierre,² Jean-Marie Rouchy,³ and Marie-Madeleine Blanc-Valleron³

ABSTRACT

The Messinian/Pliocene boundary was continuously cored in the Eastern Mediterranean at Hole 968A on the northern flank of the Eratosthenes seamount and at Holes 969A and 969B on the Mediterranean Ridge. It is marked by major changes of lithology, carbonate content, and stable isotope composition of mixed carbonate-siliciclastic sediments, which record a sharp modification of the hydric balance of the Mediterranean. During the terminal Messinian, after the salinity crisis, huge fresh-water dilution created brackish conditions of variable level of concentration in the deep shallow-water Mediterranean basins. In a period that probably lasted ~1000–2000 yr, the entire Mediterranean was refilled by marine waters at the onset of the early Pliocene so that homogeneous open-sea conditions were established in the different basins.

¹Robertson, A.H.F., Emeis, K.-C., Richter, C., and Camerlenghi, A. (Eds.), 1998. Proc. ODP, Sci. Results, 160: College Station, TX (Ocean Drilling Program).
²UMR 121, CNRS-Université-ORSTOM, Laboratoire d’Océanographie Dynamique et de Climatologie, Université Pierre et Marie Curie, 4 Place Jussieu, 75252 Paris Cedex 05, France. cat@lodyc.jussieu.fr
³URA 1761, Laboratoire de Géologie, Muséum National d’Histoire Naturelle, 43 rue Buffon, 75005 Paris, France.