The abrupt onset of the modern South Asian Monsoon winds.
The abrupt onset of the modern South Asian Monsoon winds.
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DOI：
10.1038/srep29838
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发表时间：
2016-07-20
影响因子：
4.6
通讯作者：
Young JR
中科院分区：
文献类型：
--
作者：
Betzler C;Eberli GP;Kroon D;Wright JD;Swart PK;Nath BN;Alvarez-Zarikian CA;Alonso-García M;Bialik OM;Blättler CL;Guo JA;Haffen S;Horozal S;Inoue M;Jovane L;Lanci L;Laya JC;Mee AL;Lüdmann T;Nakakuni M;Niino K;Petruny LM;Pratiwi SD;Reijmer JJ;Reolid J;Slagle AL;Sloss CR;Su X;Yao Z;Young JR
南亚季风(SAM)是最强烈的气候要素之一，但其起源和变化尚不清楚。马尔代夫IODP岩芯中的SAM风生洋流的沉积年龄为12.9 Ma，表明在短短300kyr的时间内发生了一次突然的SAM。这与地球化学示踪剂揭示的印度洋氧最小带扩张和沉积物颗粒有机质含量反映的上升流的开始相吻合。在12.9~25 Ma之间存在一个较弱的“原季风”，这与尘埃流的沉积特征相对应。除了构造控制外，SAM的突然启动还有利于气候的强烈影响，我们认为，后中新世气候最佳冷却，加上陆化作用的增加和两极海洋环流的建立，即现代世界的开始，使季风超过了一个门槛，向现代系统移动。
The South Asian Monson (SAM) is one of the most intense climatic elements yet its initiation and variations are not well established. Dating the deposits of SAM wind-driven currents in IODP cores from the Maldives yields an age of 12. 9 Ma indicating an abrupt SAM onset, over a short period of 300 kyrs. This coincided with the Indian Ocean Oxygen Minimum Zone expansion as revealed by geochemical tracers and the onset of upwelling reflected by the sediment’s content of particulate organic matter. A weaker ‘proto-monsoon’ existed between 12.9 and 25 Ma, as mirrored by the sedimentary signature of dust influx. Abrupt SAM initiation favors a strong influence of climate in addition to the tectonic control, and we propose that the post Miocene Climate Optimum cooling, together with increased continentalization and establishment of the bipolar ocean circulation, i.e. the beginning of the modern world, shifted the monsoon over a threshold towards the modern system.