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The late Miocene to Pliocene constriction of the Indonesian Gateway and its impact on ocean circulation and climate

中新世晚期至上新世印度尼西亚门户的收缩及其对海洋环流和气候的影响

基本信息

批准号：
28852969
负责人：
Professor Dr. Dirk Nürnberg
金额：
--
依托单位：
Alfred-Wegener-Institut (AWI) Helmholtz-Zentrum für Polar- und Meeresforschung
依托单位国家：
德国
项目类别：
Infrastructure Priority Programmes
财政年份：
2006
资助国家：
德国
起止时间：
2005-12-31 至 2011-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/28852969?language=en
关键词：
late Miocene Pliocene constriction Indonesian

项目摘要

Our studies focus on the Miocene to Pliocene closure of the Indonesian Gateway and its impact on changes in global ocean circulation and climate. The constriction of the Indonesian Gateway led to the formation of the modern W-Pacific warm water pool and changed ocean circulation from a predominantly latitudinal to a meridional flow. In particular, we will examine the progressive reduction of the Indonesian Throughflow within the time period from -8 to ~2.4 Ma and test the hypothesis of Cane and Molnar (2001) that the early Pliocene constriction of the Indonesian Gateway might have triggered the onset of the Northern Hemisphere Glaciation (NHG). According to general circulation models, the reduction in the Indonesian Throughflow should have led to (1) a surface cooling of the Indian Ocean, (2) a strengthened meridional heat transfer from the tropics to the Southern Ocean via an intensified East Australian Current, and (3) a weakening of the Leeuwin Current on the western side of Australia. Four DSDP/ODP Sites were selected to investigate these proposed changes: Site 756 (214) from the tropical east Indian Nürnberg/Tiedemann: Indonesian Gateway Ocean, Site 763 below the Leeuwin Current, and Sites 580 and 1172 within the influence of the East Australian Current. The combined measurement of planktic foraminiferal Mg/Ca and 51SO will allow to reconstruct sea-surface (subsurface) temperatures, thermocline depth and salinities at a temporal resolution for the Miocene/Pliocene time slice not yet available, and will allow to decipher hydrographic changes during the constriction of the Indonesian Throughflow.

我们的研究重点是中新世到上新世印度尼西亚门户的关闭及其对全球海洋环流和气候变化的影响。印度尼西亚海峡的收缩导致了现代西太平洋暖水池的形成，并将海洋环流从主要的纬向流改变为纬向流。特别是，我们将研究在-8Ma到~ 2.4Ma的时间段内印度尼西亚洋流的逐渐减少，并检验Cane和Molnar（2001）的假设，即印度尼西亚门户的上新世早期收缩可能引发了北方半球冰川（NHG）的开始。根据大气环流模式，印度尼西亚洋流的减少应该导致（1）印度洋表面冷却，（2）通过增强的东澳大利亚海流加强从热带到南大洋的纬向热传递，以及（3）澳大利亚西侧的列文海流减弱。选择了四个DSDP/ODP站点来调查这些拟议的变化：来自热带东印度纽伦堡/蒂德曼的站点756（214）：印度尼西亚门户海洋，Leeuwin海流以下的站点763，以及东澳大利亚海流影响范围内的站点580和1172。南极有孔虫Mg/Ca和51 SO的联合测量将能够重建海洋表面（地下）温度，温跃层深度和盐度，时间分辨率为中新世/上新世时间片尚未提供，并将能够破译印度尼西亚洋流收缩期间的水文变化。