Co-evolution of monsoonal precipitation in East Asia and the tropical Pacific ENSO system since 2.36 Ma: New insights from high-resolution clay mineral records in the West Philippine Sea
Co-evolution of monsoonal precipitation in East Asia and the tropical Pacific ENSO system since 2.36 Ma: New insights from high-resolution clay mineral records in the West Philippine Sea
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2.36 Ma以来东亚季风降水与热带太平洋ENSO系统的共同演化：西菲律宾海高分辨率粘土矿物记录的新见解
DOI：
10.1016/j.epsl.2016.04.022
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发表时间：
2016
影响因子：
5.3
通讯作者：
Li Tiegang
中科院分区：
文献类型：
--
作者：
Yu Zhaojie;Wan Shiming;Colin Christophe;Yan Hong;Bonneau Lucile;Liu Zhifei;Song Lina;Sun Hanjie;Xu Zhaokai;Jiang Xuejun;Li Anchun;Li Tiegang
通过对宾汉海隆（MD 06 -3050）深海沉积物的粘土矿物学分析和扫描电镜（SEM）分析，重建了2.36 Ma以来东亚夏季风（EASM）降水的长期演变过程。粘土矿物学的变化是由于蒙皂石的比例的变化，这是从吕宋岛的火山岩在强烈的季风降雨的时间间隔，伊利石和绿泥石丰富的灰尘，这是从东亚运输的风与东亚冬季季风（EAWM）的风化。由于吕宋岛是宾汉隆起蒙皂石的主要来源，蒙皂石的长期一致变化/MD 06岩芯中的（伊利石+伊利石）比值-南海北方ODP 1146站和3050站的研究结果表明，在2360年以来的时间间隔内，风成尘的少量贡献在矿物学比值的变化中发挥了作用，并表明东亚夏季风降水的加强至1900千年、1200至600千年以及200千年之后。东亚夏季风的降雨记录显示出30 kyr的周期性，这表明厄尔尼诺-南方涛动（ENSO）的影响。吕宋岛降水增强的时间间隔与中国中部降水的减少和赤道太平洋纬向SST梯度的增加是同期的，这意味着拉尼娜条件的加强。相反，吕宋岛降水减少的时期与中国中部的降水量增加和赤道太平洋纬向SST梯度减弱有关，从而表明主要的厄尔尼诺条件的发展。因此，我们的研究，第一次突出了长期的时间和空间的共同演变的季风降水在东亚和热带太平洋ENSO系统在过去的2.36 Ma。
Clay mineralogical analysis and scanning electron microscope (SEM) analysis were performed on deep-sea sediments cored on the Benham Rise (core MD06-3050) in order to reconstruct long-term evolution of East Asian Summer Monsoon (EASM) rainfall in the period since 2.36 Ma. Clay mineralogical variations are due to changes in the ratios of smectite, which derive from weathering of volcanic rocks in Luzon Island during intervals of intensive monsoon rainfall, and illite- and chlorite-rich dusts, which are transported from East Asia by winds associated with the East Asian Winter Monsoon (EAWM). Since Luzon is the main source of smectite to the Benham Rise, long-term consistent variations in the smectite/(illite + chlorite) ratio in core MD06-3050 as well as ODP site 1146 in the Northern South China Sea suggest that minor contributions of eolian dust played a role in the variability of this mineralogical ratio and indicate strengthening EASM precipitation in SE Asia during time intervals from 2360 to 1900 kyr, 1200 to 600 kyr, and after 200 kyr. The EASM rainfall record displays a 30 kyr periodicity suggesting the influence of El Niño–Southern Oscillation (ENSO). These intervals of rainfall intensification on Luzon Island are coeval with a reduction in precipitation over central China and an increase in zonal SST gradient in the equatorial Pacific Ocean, implying a reinforcement of La Niña-like conditions. In contrast, periods of reduced rainfall on Luzon Island are associated with higher precipitation in central China and a weakening zonal SST gradient in the equatorial Pacific Ocean, thereby suggesting the development of dominant El Niño-like conditions. Our study, therefore, highlights for the first time a long-term temporal and spatial co-evolution of monsoonal precipitation in East Asia and of the tropical Pacific ENSO system over the past 2.36 Ma.