西菲律宾海盆东部第四纪沉积物磁学记录及其古气候意义  

Magnetic Records of Quaternary Sediments in the Eastern West Philippine Sea Basin and Its Paleoclimatic Implications

作　　者：孙军[1,2,3,4] 吴怀春 黄威[2,3] 路晶芳 时美楠 王双[3] 李博雅[1] 虞义勇 陈晓辉 强小科 陆凯[3] Sun Jun;Wu Huaichun;Huang Wei;Lu Jingfang;Shi Meinan;Wang Shuang;Li Boya;Yu Yiyong;Chen Xiaohui;Qiang Xiaoke;Lu Kai(School of Ocean Sciences,China University of Geosciences(Beijing),Beijing 100083,China;Laboratory for Marine Mineral Resources,Qingdao Marine Science and Technology Center,Qingdao 266237,China;Qingdao Institute of Marine Geology,China Geological Survey,Qingdao 266237,China;Key Laboratory of Polar Geology and Marine Mineral Resources,Ministry of Education,China University of Geosciences(Beijing),Beijing 100083,China;State Key Laboratory of Loess Science,Institute of Earth Environment,Chinese Academy of Sciences,Xi’an 710061,China)

机构地区：[1]中国地质大学(北京)海洋学院,北京100083 [2]青岛海洋科技中心海洋矿产资源评价与探测技术功能实验室,山东青岛266237 [3]中国地质调查局青岛海洋地质研究所,山东青岛266237 [4]中国地质大学(北京)极地地质与海洋矿产教育部重点实验室,北京100083 [5]中国科学院地球环境研究所黄土科学全国重点实验室,陕西西安710061

出　　处：《地球科学》2025年第3期918-933,共16页Earth Science

基　　金：中国地质调查局项目(NoS.DD20221720,DD20230643,DD20191003,DD20242758);极地地质与海洋矿产教育部重点实验室开放基金资助项目(No.PGMR-2023-101).

摘　　要：为深入研究菲律宾海风尘输入对亚洲内陆气候变化的响应,对西菲律宾海盆东部的QYZ01孔柱状样沉积物开展详细的岩石磁学和古磁学研究,建立第四纪磁性地层年代框架,探讨第四纪以来沉积物磁学特征指示的亚洲内陆风尘输入、东亚冬季风强度变化.结果表明,QYZ01孔沉积物的磁性矿物主要为陆源碎屑成因的、低矫顽力的单畴磁铁矿.QYZ01孔岩心记录了从Brunhes正极性时至Matuyama负极性时下部,包括Jaramillo、Olduvai和Réunion正极性亚时.根据沉积速率推算钻孔底部年龄为~2.43 Ma.早、中更新世界线(M/B界线)位于200 cm深度处.环境磁学指标χ_(ARM)/SIRM比值揭示钻孔所在研究区2.43 Ma以来东亚冬季风强度和亚洲内陆风尘输入的整体和阶段性加强,并在2.43~1.86 Ma、1.86~1.0 Ma、1.0~0.5 Ma、0.5~0 Ma四个阶段表现出不同的变化特征.本研究为深入理解亚洲内陆气候变化和东亚季风演变提供了新的认识.The Philippine Sea is an important sink area for eolian dust from the Asian interior carried by East Asian winter monsoon(EAWM),and its continuous sedimentary sequences provide important geological archives for studying the variation of the EAWM and the history of aridification of the Asian interior.However,environmental magnetic records over long time scales with a reliable chronological framework from this area are scarce.In this study,we conducted detailed rock magnetic and paleomagnetic studies on deep-sea sediments of a 5.12 m core(QYZ01)recovered from the eastern West Philippine Sea Basin,Philippine Sea.Our aims are to establish a reliable Quaternary chronological framework,and to reveal the Asian eolian dust input and the evolution of the intensity of EAWM according to the changes of the environmental magnetic characteristics of sediments.Rock magnetic results show that low-coercivity magnetite with SSD magnetic behavior is the dominant magnetic carrier in the sediments,and it may mainly originate from detrital sources.The paleomagnetic result suggest that the sequence recorded the early Matuyama reverse chron to the Brunhes normal chron,including the Jaramillo,Olduvai and Réunion normal subchrons,and the basal age was estimated to be~2.43 Ma.The Matuyama/Brunhes boundary was found at the core depth of~200 cm.The environmental magnetic proxy(χ_(ARM)/SIRM)indicates that the EAWM intensity and the Asian eolian dust input of the area around the QYZ01 core have shown an overall increasing trend since 2.43 Ma,and further divided into four phased variation patterns.The changes inχ_(ARM)/SIRM ratio reflect the glacier expansion in the high latitudes of the northern Hemisphere and the phased uplift of the Qinghai-Xizang Plateau since the Quaternary,which led to the intensified aridification in the Asian interior and strengthened EAWM.This study provides new insights into understanding the paleoclimate changes in Asian interior and the evolution process of East Asian monsoon during the Quaternary.

关 键 词：菲律宾海 环境磁学 亚洲风尘 磁性矿物 东亚季风 沉积学 气候变化 

分 类 号：P736[天文地球—海洋地质]