East Asian monsoon evolution since the late Miocene from the South China Sea
East Asian monsoon evolution since the late Miocene from the South China Sea
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晚中新世以来南海东亚季风演化
DOI：
10.1016/j.epsl.2019.115960
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发表时间：
2020-01-15
影响因子：
5.3
通讯作者：
Liu, Jianxing
中科院分区：
文献类型：
--
作者：
Gai, Congcong;Liu, Qingsong;Liu, Jianxing
南海因其地理位置对东亚季风和太平洋变化的敏感性而成为全球古气候和古海洋学研究的热点。我们在这里提出了一个精细的磁性地层学的最后6.5 Ma的孔U1431 D，这是恢复在IODP远征349在南海中部。磁性分析表明，除130.5-132.0米的含灰岩层外，磁铁矿是主要的磁性载体。云英石层与北方冰川作用加剧的时间相吻合，并记录了对这一事件的海洋学反应。环境磁学结果表明，东亚夏、冬季风在6.5 ~ 5 Ma期间是稳定的。夏季风在5 Ma时增强，3.8Ma以后逐渐减弱。相比之下，冬季风在5 Ma时减弱，3.8 Ma后增强，0.6 Ma后稳定。谱分析表明，东亚夏季风在3.2Ma以前是由低纬太阳辐射变化直接驱动的，而在3.2Ma以后则是由低纬太阳辐射和高纬冰量变化共同驱动的。(C)2019 Elsevier B. V.版权所有。
The South China Sea (SCS) has become a global focus for paleoclimatic and paleoceanographic studies due to its location, which makes it highly sensitive to the East Asian monsoon and to Pacific Ocean changes. We present here a refined magnetostratigraphy for the last 6.5 Ma for Hole U1431D, which was recovered during IODP Expedition 349 in the central SCS. Magnetic analyses demonstrate that magnetite is the dominant magnetic carrier except for within a greigite-bearing layer at 130.5-132.0 meters below sea floor. The greigite layer coincides with the timing of intensification of northern hemisphere glaciation and records an oceanographic response to this event. Environmental magnetic results indicate that the East Asian summer and winter monsoon were stable from 6.5 to 5 Ma. The summer monsoon intensified at 5 Ma, and then weakened gradually since 3.8 Ma. In contrast, the winter monsoon weakened at 5 Ma, and has then been enhanced since 3.8 Ma and more stable from 0.6 Ma. Spectral analysis indicates that the East Asian summer monsoon was driven directly by low-latitude insolation changes before similar to 3.2 Ma, and that it has been affected by both low-latitude insolation and high-latitude ice volume changes since similar to 3.2 Ma. (C) 2019 Elsevier B.V. All rights reserved.