The IMMAGE proposal is part of a drilling project that aims to recover a complete sedimentary record of the Atlantic-Mediterranean exchange before, during and after the Messinian Salinity Crisis (MSC).
Marine gateways play a critical role in the exchange of water, heat, salt and nutrients between oceans and seas. Changes in gateway geometry can therefore significantly alter both the pattern of global ocean circulation and associated heat transport and climate, as well as having a profound local impact. For the past five million years Mediterranean seawater has flowed out of the Gibraltar Straits, forming a saline plume at intermediate depths in the Atlantic that contributes to Atlantic Meridonal Overturning Circulation, and deposits distinctive contouritic sediments in the Gulf of Cadiz. However, before the Pliocene, two additional marine corridors also existed through northern Morocco and southern Spain.
The restriction and closure of these connections resulted in extreme salinity fluctuations in the Mediterranean, leading to the precipitation of thick Messinian Salinity Crisis evaporites. Understanding both the causes of high-amplitude salinity change in the Mediterranean and its consequences for thermohaline circulation in the Atlantic and other aspects of the global climate system, is dependent on recovering a complete record of Mediterranean-Atlantic exchange before, during and after the MSC.