CHRONOSTRATIGRAPHY AND TRANSGRESSION/REGRESSION DURING LATE PLEISTOCENE IN THE SOUTHERN CHANGJIANG (YANGTZE) RIVER DELTA PLAIN
CHRONOSTRATIGRAPHY AND TRANSGRESSION/REGRESSION DURING LATE PLEISTOCENE IN THE SOUTHERN CHANGJIANG (YANGTZE) RIVER DELTA PLAIN
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发表时间：
2004
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通讯作者：
Wang Zhang-hua;M. Key
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作者：
Wang Zhang-hua;M. Key
对长江三角洲平原南部晚第四纪4个钻孔进行了定年和微化石分析，以表征晚更新世的年代学和海平面变化。研究表明，岩心深度100~145 m的蓝灰色硬泥沉积时间为~110 ~ 120 kaBP，是中更新世末期的标志。岩心深度15~30 m处的墨绿色或棕黄色硬泥沉积时间为10 ~ 17 kaBP，为晚更新世末期。研究区在110~60 kaBP期间以河流砾石砂为主，在100~80 kaBP期间发生了一次弱海侵，形成了淹没谷。60 ~ 40 kaBP、40 ~ 34 kaBP和34 ~ 22 kaBP分别出现粗—细—粗3层序。研究区西部在40~34 kaBP期间发现了硬泥。钻孔MFC中发现60~ 22kabp的连续海侵沉积。在43~40 kaBP和34~22 kaBP分别发现了两个最强的海平面变化。
Dating and microfossil analysis was conducted on four boreholes of late Quaternary deposit in the southern Changjiang(Yangtze)River delta plain to characterize the chronology and sea-level changes during the late Pleistocene. Our work shows that the blueish gray stiff mud at core depth of 100～145 m was deposited from ～110 to 120 kaBP, serving as the symbol of the end of the mid Pleistocene. The dark green or brownish yellow stiff mud at core depth of 15～30 m was deposited from 10 to 17 kaBP, serving as the end of the late Pleistocene. Fluvial gravelly sand prevailed in the study area during 110～60 kaBP, and a weak transgression occurred during 100～80 kaBP, forming a drowned valley. Three sedimentary sequences (coarse-fine-coarse) appeared from 60 to 40 kaBP, from 40 to 34 kaBP, and from 34 to 22 kaBP respectively. Stiff mud was found in the west part of the study area during 40～34 kaBP. Continuous transgressive deposits of 60～22 kaBP were found in borehole MFC. Two strongest sea-level changes were discovered at 43～40 kaBP and 34～22 kaBP respectively.