渐新世-中新世东南亚干湿气候格局演变及驱动机制  

Preliminary study on Oligo-Miocene hydrological changes in Southeast Asia and their driving mechanisms

作　　者：胡建雄 黄恩清[1] 田军[1] HU Jianxiong;HUANG Enqing;TIAN Jun(State Key Laboratory of Marine Geology,Tongji University,Shanghai 200092,China)

机构地区：[1]同济大学海洋地质国家重点实验室,上海200092

出　　处：《海洋地质与第四纪地质》2024年第4期16-31,共16页Marine Geology & Quaternary Geology

基　　金：国家重点研发计划“新近纪晚期印太暖池地区海道关闭与高纬冰盖演变的耦合机制研究”(2023YFF0803902)。

摘　　要：新生代印尼海道的启闭对印度-太平洋暖池演化和大气环流模式变迁有重大影响。然而,受限于构造和古环境重建资料的缺乏,这三者之间的逻辑关系和驱动机制还缺乏清晰的图景。本文梳理了孢粉记录、煤层沉积、浅海碳酸盐沉积和生物地理演化等方面的证据,提出东南亚水文气候在渐新世与中新世之交发生重大调整的认识,即从渐新世的相对干旱条件转型为贯穿整个中新世的持续湿润状态。结合最近的模拟研究,认为东南亚水文气候演变同时受到全球因素和区域构造要素的影响。渐新世与中新世之交和中中新世晚期至晚中新世早期,印尼海道的持续关闭可以通过限制太平洋-印度洋次表层水的交换,进而扩大太平洋一侧的温跃层深度以及经纬向的海表温度梯度,进一步增强沃克环流,最终可能促使东南亚在渐新世与中新世之交发生了干湿格局的转换,并抵消了中中新世晚期至晚中新世全球降温对区域水文气候的影响。目前的研究仍存在不确定性,未来亟需更多的地质记录和模拟研究来准确厘定海道关闭-暖池演化-大气环流之间的联系。The closure of the Indonesian Seaway played a key role in the evolution of the Indo-Pacific Warm Pool and associated atmospheric circulation during the Cenozoic.However,the relationship between the closure of the seaway,the evolution of the warm pool,and the shift in atmospheric circulation remains unclear due to poor constraints in tectonic and paleoenvironmental reconstructions.This study reviews the historical literature,including evidence from pollen records,coal deposits,shallow marine carbonate deposits,and biogeographic evolution.The results show that the hydroclimate in Southeast Asia underwent significant changes during the Oligo-Miocene transition,shifting from relatively dry conditions in the Oligocene to persistently wet conditions throughout the Miocene.Combined with recent simulation studies,it was concluded that the hydrological changes in Southeast Asia were influenced by both global and regional factors.The narrowing and closure of the seaway may have increased the gradient between the east-west thermocline depth and the east-west sea surface temperature in the Pacific Ocean,limiting the exchange of subsurface water between the Pacific and Indian Oceans.This in turn led to a strengthening of the Walker Circulation,which subsequently induced hydrological changes in Southeast Asia after the Oligo-Miocene boundary and mitigated the effects of global cooling over the Late Miocene.Uncertainties remain in current studies,and more geological records and simulation studies in the future would help to accurately characterize the relationship between seaway closure,warm pool evolution,and atmospheric circulation in the Oligo–Miocene.

关 键 词：水文循环 东南亚 渐新世-中新世 印尼海道 印度-太平洋暖池 

分 类 号：P736.22[天文地球—海洋地质]