Benthic foraminifera distribution and stable isotope record of ODP Hole 160-963A@en

New centennial-scale data of benthic foraminifera assemblages and of stable isotopes of foraminifera shells from the Sicily Channel, representative of surface and bottom waters, over the interval between about 140 and 110 kyr BP, are presented. During this period anoxia developed on the eastern Mediterranean basin and sapropel S5 deposited. Although anoxic sediments have not been deposited in the Sicily Channel, this area is strategic to study the character of intermediate waters, whose chemical-physical properties strongly precondition the eastern Mediterranean deep water formation. So far, no data from these water masses have been obtained, apart from the isotopic composition of shells of the planktonic foraminifera species Neogloboquadrina pachyderma which lives at about 200 m depth, thus quite far from the intermediate water core. We conclude that, although with a reduced rate, the flowing of intermediate waters coming from the eastern basin, together with the surface water masses with a clear western affinity, implies the maintenance of an anti-estuarine circulation pattern across the Sicily Channel and in the Mediterranean Sea, also during one of the most severe episodes of anoxia of the Late Pleistocene.本研究报道了西西里海峡（Sicily Channel）距今约140~110千年（kyr BP）时段内的百年尺度底栖有孔虫（benthic foraminifera）组合及有孔虫壳体稳定同位素数据，该数据集可表征该区域表层与底层水体的环境特征。该时段内，东地中海盆地发生缺氧事件并沉积了腐泥层S5（sapropel S5）。尽管西西里海峡并未沉积缺氧沉积物，但该区域是研究中层水（intermediate waters）特征的关键区域——中层水的理化性质对东地中海深层水的形成具有极强的先决调控作用。迄今为止，除针对生活在约200米水深的浮游有孔虫（planktonic foraminifera）物种厚壳新球虫（Neogloboquadrina pachyderma）的壳体同位素组成开展过分析外，尚未获取该水团的直接观测数据，而该水深距离中层水核心区域甚远。本研究得出结论：尽管流速有所降低，但来自东盆地的中层水与具有显著西源属性的表层水团共同作用，表明在晚更新世（Late Pleistocene）最严重的缺氧事件之一期间，西西里海峡及地中海全域仍维持着逆河口环流（anti-estuarine circulation）模式。