Mineral Magnetic Properties and Late Quaternary Transgressions Recorded by the Borehole WJ in the Taihu Plain, China
Mineral Magnetic Properties and Late Quaternary Transgressions Recorded by the Borehole WJ in the Taihu Plain, China
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DOI：
10.1002/cjg2.20060
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发表时间：
2013-09
期刊：
影响因子：
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通讯作者：
C. Ting;Wang Zhanghua;Qiang Xiaoke;Ma Chun-yan;Zhan Qing
中科院分区：
文献类型：
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作者：
C. Ting;Wang Zhanghua;Qiang Xiaoke;Ma Chun-yan;Zhan Qing
利用古地磁和AMS14C测年结果，对长江三角洲南部太湖平原WJ钻孔沉积物的岩性、粒度、磁性和有孔虫进行了研究，重建了晚第四纪沉积环境演化和海侵事件。研究了磁指标在河口三角洲沉积环境识别中的应用。结果表明，WJ钻孔沉积序列可划分为中更新世ⅰ期、中更新世ⅱ期、晚更新世和全新世4个时期。其沉积地貌条件分别为河流-湖泊平原、海岸-阶地、河口坝-河口-潮坪阶地和湖泊平原。WJ钻孔揭示了3次海侵事件，分别发生在中更新世晚期、晚更新世海相同位素阶段（MIS） 5和MIS3。MIS5e期海侵最强，MIS3期后期海侵明显加剧。滩涂和河口坝沉积物的磁性最强，χ f、SIRM和HIRM值均较高。
With paleomagnetism and AMS14C dating results, we reconstructed the depositional environmental evolution and marine transgression events during the Late Quaternary by examining the lithology, grain size, magnetic properties, and foraminifera of sediments from a borehole WJ in the Taihu plain of southern Yangtze Delta, China. We also investigated the application of magnetic proxies to distinguishing depositional environments in the estuarine-deltaic area. The results show that the sediment sequence of borehole WJ could be divided into four periods including Mid-Pleistocene stage I, Mid-Pleistocene stage II, Late Pleistocene, and Holocene. Their depositional geomorphological conditions were fluvial-lacustrine plain, coast-terrace, mouth bar-estuary-tidal flat-terrace, and lacustrine plain, respectively. Three transgression events were revealed by the borehole WJ, which happened during the late stage of Mid-Pleistocene, marine isotope stage (MIS) 5 and MIS3 of Late-Pleistocene. The MIS5e transgression was the strongest one and the transgression in the late stage of MIS3 intensified significantly. Magnetic properties were strongest in the tidal flat and mouth bar sediments, with notably high values of χlf, SIRM and HIRM.