Magnetic Records of Quaternary Sediments in the Eastern West Philippine Sea Basin and Its Paleoclimatic Implications
Sun Jun
Wu Huaichun
Huang Wei
Lu Jingfang
Shi Meinan
Wang Shuang
Li Boya
Yu Yiyong
Chen Xiaohui
Qiang Xiaoke
Lu Kai
Abstract：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(χARM/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 in χARM/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.
Keywords：Philippine Seaenvironmental magnetismAsian eolian dustmagnetic mineralEast Asian monsoonsedimentologyclimate change
Publication Date：2025-03-14
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：16( 918-933 )