The Mediterranean-Atlantic water mass exchange provides the ideal setting for deciphering the role of gateway evolution in ocean circulation. However, the dynamics of Mediterranean Outflow Water (MOW) during the closure of the Late Miocene Mediterranean-Atlantic gateways are poorly understood. Here, we define the sedimentary evolution of Neogene basins from the Gulf of Cádiz to the West Iberian margin to investigate MOW circulation during the latest Miocene. Seismic interpretation highlights a middle to upper Messinian seismic unit of transparent facies, whose base predates the onset of the Messinian salinity crisis (MSC). Its facies and distribution imply a predominantly hemipelagic environment along the Atlantic margins, suggesting an absence or intermittence of MOW preceding evaporite precipitation in the Mediterranean, simultaneous to progressive gateway restriction. The removal of MOW from the Mediterranean-Atlantic water mass exchange reorganized the Atlantic water masses and is correlated to a severe weakening of the Atlantic Meridional Overturning Circulation (AMOC) and a period of further cooling in the North Atlantic during the latest Miocene.

地中海-大西洋水质交换为解密通道演化在海洋环流中的作用提供了理想的环境。然而，人们对中新世晚期地中海大西洋通道关闭期间的地中海流出水（MOW）的动态了解甚少。在这里，我们定义了从加的斯湾到西伊比利亚边缘的新近纪盆地的沉积演化，以研究最新中新世期间的MOW环流。地震解释突出了透明相的墨西尼中上地震单元，其基础早于墨西尼盐度危机（MSC）的发作。它的相貌和分布暗示着大西洋边缘地区主要是半裙带性环境，这表明在地中海蒸发气沉积之前，MOW缺乏或存在间歇性，与渐进式网关限制同时进行。从地中海-大西洋水质交换所去除的MOW重组了大西洋水质，这与大西洋中子午翻覆环流（AMOC）的严重减弱以及最近中新世时期北大西洋的进一步降温有关。