ICDP workshop on amphibious drilling to Investigate Miocene Mediterranean-Atlantic Gateway Exchange (IMMAGE)

Startdate: 22 November, 2016
Enddate: 24 November, 2016

Status: done

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 evaporites during the Messinian Salinity Crisis (MSC). Understanding both the causes of high-amplitude salinity change in the Mediterranean, its impact on the position and nature of the plume of water formed by Mediterranean overflow, and the consequences for thermohaline circulation in the Atlantic, is dependent on recovering a complete record of Mediterranean-Atlantic exchange before, during and after the MSC. These sediments would also allow us to test physical oceanographic hypotheses for extreme high density overflow dynamics that do not exist in the world today on this scale.