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篇目详细内容 |
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【篇名】 |
Sedimentary facies of the central part of radial tidal sand ridge system of the eastern China coast |
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【刊名】 |
Frontiers of Earth Science in China |
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【刊名缩写】 |
Front. Earth Sci. China |
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【ISSN】 |
1673-7385 |
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【EISSN】 |
1673-7490 |
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【DOI】 |
10.1007/s11707-008-0053-6 |
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【出版社】 |
Higher Education Press and Springer-Verlag |
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【出版年】 |
2008 |
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【卷期】 |
2
卷4期 |
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【页码】 |
408-417
页,共
10
页 |
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【作者】 |
YIN Yong;
ZOU Xinqin;
ZHU Dakui;
HUANG Jiaxiang;
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【关键词】 |
sedimentary facies; tidal sand ridge-channel system; sandy ridge migration; South Yellow Sea offshore |
【摘要】 |
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A unique radial tidal sand ridge system (RTSRS) has developed under a complex tidal current field on the eastern China coast between the Yangtze River delta to the south and the abandoned Yellow River (Huanghe) delta to the north. The present study examines the sedimentary evolution of a ridge-channel pair in the central RTSRS. Three cores, with two on the ridges and one in the channel, were drilled to reveal the late Pleistocene-Holocene deposits of the system. Five sedimentary facies were distinguished, i.e. ridge-shallow subtidal facies, ridge-deep subtidal facies, near-surface channel bottom facies, middle tidal flat facies and low tidal flat facies. The ridge-shallow subtidal facies consists of sandy strata with ripple cross beddings, horizontal lamina, and massive beddings. Bioturbation seldom occurs. The ridge-deep subtidal facies is primarily characterized by sandy and muddy interlayers with common flaser and lenticular bedding structures. Bioturbation appears abundantly. Massive and graded sediment sequences of storm origin are present as characterized by rich shell fragments. The near-surface channel bottom facies consists of loose, soft, clayey silt deposits with deformed sedimentary layers. This facies occurs in the deeper part of the active channels. The middle tidal flat and lower tidal flat facies composed of silt-clay couplets prevailed primarily in the tidal flats. Incomplete sedimentary successions show that coastal plain deposits dominate in the study area during 12–13 ka B.P. The sandy ridge and channel facies became dominant during 4–6 ka B.P. when the sea level receded temporarily. Tidal ridge and channel in the study area became active during the last four decades. Sediment reworking due to typhoon and sandy ridge migration plays a key role in shaping the present radial ridge system. |
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