The onset of the Messinian salinity crisis: Insights from Cyprus sections

Abstract

The Neogene basins of Southern Cyprus provide a good opportunity to improve the knowledge of the paleoenvironmental changes involved in the triggering of the Messinian evaporite deposition in the Mediterranean, and of their chronology, which is still questionable with regards to the parameters responsible for the triggering of the salinity crisis. It is still difficult to discriminate the individual effects of tectonics, climate, global sea-level changes. In Cyprus, considerable progress has been made on the events leading to the MSC, since the 70's, in high-resolution microfossil biostratigraphy, astrochronology, cyclostratigraphy and magnetostratigraphy. A study of the Tochni section, in the Psematismemos Basin, correlated with previously studied sections in the western Polemi and Pissouri basins, allows these regional paleoenvironmental changes to be correlated with the major events identified in other Mediterranean basins. The depth of the basins, in which evaporites were deposited, and the increase of salinity leading to the formation of evaporites are better constrained and studies confirm that restriction proceeded by steps throughout the Mediterranean. The very short time involved in the triggering of the onset of evaporite deposition in Cyprus basins is marked by tectonic instability, and development of very shallow water fauna and microbial communities indicating the water level lowered significantly just before the beginning of the massive gypsum precipitation. Correlation with other peri-Mediterranean basins, where similar changes have been observed, confirms that the period preceding the deposition of evaporites may correspond to the final closure of connections between the Atlantic Ocean and the Mediterranean Basin, leading to a sea-level drop and important hydrologic changes.