Eastern Mediterranean surface water temperatures and delta O-18 composition during deposition of sapropels in the late Quaternary
Eastern Mediterranean surface water temperatures and delta O-18 composition during deposition of sapropels in the late Quaternary
复制标题
DOI：
--
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
K. Emeis;H. Schulz;U. Struck;M. Rossignol-Strick;H. Erlenkeuser;M. Howell;D. Kroon;A. Mackensen;S. Ishizuka;T. Oba;T. Sakamoto;I. Koizumi
中科院分区：
文献类型：
--
作者：
K. Emeis;H. Schulz;U. Struck;M. Rossignol-Strick;H. Erlenkeuser;M. Howell;D. Kroon;A. Mackensen;S. Ishizuka;T. Oba;T. Sakamoto;I. Koizumi
[ 1 ]在第四纪晚期，从寒冷到温暖的气候转变期间，水柱分层增加，导致地中海东部盆地深处的缺氧条件和腐泥形成。晚更新世腐泥层段的海表温度（SST）（根据U 37 k 0指数估算）和浮游有孔虫方解石（d 18 O fc）的d 18 O高分辨率数据集显示，d 18 O fc下降（在1和4.6%之间），SST上升（在0.7（cid：2）和6.7（cid：2）C之间）。最大d 18 O海水损耗东地中海表面沃茨在过渡是0.5和3.0%之间，在所有情况下，但一个超过了在西地中海核心的损耗。在d 18 O海水的枯竭是最明显的腐泥基地，在协议的季风淡水的初始突然输入。大多数腐泥与SST的变暖趋势一致。最初的淡水输入和海面持续变暖导致的密度下降汇集了表层的淡水，并阻止了在寒冷和干旱的冰川条件下沉积的深层水的深层对流。这种模式的一个例外是“冰川”腐泥S6;其最大的d 18 O海水消耗（3%）几乎与地中海西部的消耗相匹配，并且伴随着地表水冷却，随后是最初的快速升温阶段。第二个时期的显着同位素枯竭是在同位素阶段6在150 kyr的日照最大。虽然由于寒冷而没有表现为腐泥
[ 1 ] Water column stratification increased at climatic transitions from cold to warm periods during the late Quaternary and led to anoxic conditions and sapropel formation in the deep eastern Mediterranean basins. High-resolution data sets on sea-surface temperatures (SST) (estimated from U 37k 0 indices) and d 18 O of planktonic foraminifer calcite ( d 18 O fc ) across late Pleistocene sapropel intervals show that d 18 O fc decreased (between 1 and 4.6 % ) and SST increased (between 0.7 (cid:2) and 6.7 (cid:2) C). Maximal d 18 O seawater depletion of eastern Mediterranean surface waters at the transition is between 0.5 and 3.0 % , and in all but one case exceeded the depletion seen in a western Mediterranean core. The depletion in d 18 O seawater is most pronounced at sapropel bases, in agreement with an initial sudden input of monsoon-derived freshwater. Most sapropels coincide with warming trends of SST. The density decrease by initial freshwater input and continued warming of the sea surface pooled fresh water in the surface layer and prohibited deep convection down to ageing deep water emplaced during cold and arid glacial conditions. An exception to this pattern is ‘‘glacial’’ sapropel S6; its largest d 18 O seawater depletion (3 % ) is almost matched by the depletion in the western Mediterranean Sea, and it is accompanied by surface water cooling following an initially rapid warming phase. A second period of significant isotopic depletion is in isotope stage 6 at the 150 kyr insolation maximum. While not expressed as a sapropel due to cold