Possible paleo-exchange of water masses between the Mediterranean Sea, Marmara Sea and Black Sea

Abstract

In this article a way for possible paleo-exchange of water masses between the Aegean, the Marmara and the Black Sea is submitted. A key aspect according to the interpretation on hand of the possible paleo-exchange of water masses is the depth of the Bosphorus sill for the period 20000 - 7000 cal. yr. BP. Determining an established constant depth for the Bosphorus sill for the period of 20000 - 7000 cal. yr. BP is an incorrect approach to the interpretation of the paleo-climatic and paleo-geological events in the Black Sea region. Due to this reason two models of the Bosphorus sill - deep sill and shallow sill models have been accepted. The deep sill model is valid for the first two stages of the period 20 000 - 14 500 cal. yr. BP. The shallow sill model is valid for the period ~12500-7000 cal. yr. BP. For the last stage of possible paleo-exchange of water masses between Aegean, Marmara and Black Seas (7500-7000 cal. yr. BP) as a result of continuing increase in the global sea level, saline ocean water catastrophically entered the Black Sea. The new moment of possible paleo-exchange of water masses between Aegean, Marmara and Black Seas is that once started the freshwater Black Sea outflow to the Marmara Sea in 14000 cal. yr. BP did not stop until about 12500 cal. yr. BP but continued to about 9500 cal. yr. BP. That contradicts the theory of Ryan et. al., (1997), Aksu et al. (2002). A new explanation for the formation of the lower sapropel layer in the Marmara Sea has been offered.