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Please use this identifier to cite or link to this item: http://ntour.ntou.edu.tw:8080/ir/handle/987654321/24899

Title: Preliminary study of Quaternary stratigraphy and palynology in the Yangtze Delta, eastern China
Authors: Chen Z.-Y.;M.-T. Chen
Contributors: NTOU:Institute of Applied Geosciences
Date: 1996
Issue Date: 2011-10-20T08:18:07Z
Publisher: Journal of the Geological Society of China
Abstract: abstract:Based on a series of core sample analyses of petrology, lithology, fossil/flora, and paleomagnetism on a long sediment borehole Ch-1, located on the southern bank of the southern Yangtze distributary, research on Quaternary stratigraphy and palynology of the study area was carried out to focus on the aspects of 1) four subdivisions of stratigraphic sections: the Early (Q1), Middle (Q2), Late Pleistocene (Q3), and the Holocene (Q4); 2) six major fluvial to marine cyclicities and one delta sequence; 3) six differentiated lithofacies; and 4) six zonations and eight assemblages of pollen spores. From the core bottom upward, the lithofacies are generally in turn the fluvial, lacustrine, coastal, drowned river channel, shallow marine and delta. Terrigenous lithofacies prevailed during the Q1 and Q2; coastal to drowned river channels occurred periodically during the Q1, Q2 and Q3; and shallow marine and delta dominated the Q3 and Q4, respectively. Thus, four transgressions separated by non-marine-influenced terrigenous sediments were revealed in the Quaternary sediment sequences of the study area. Six zonations and eight pollen spore assemblages have been recognized from different Quaternary sections, indicating a series of cold and warm stages and paleoclimatic changes. The paleoclimate at the beginning of the Quaternary was cold and then periodically changed with warm and cold stages, as time progressed into the Holocene. Two paleoclimate extremes were recorded by distinct presences of pollen spores during the Quaternary: Assemblage IV demonstrates the coldest weather of the latest period of the Late Pleistocene, while Assemblage VI, the hottest climate of the mid-Holocene. In most cases, the paleoclimate and eustatic records in the Q2, Q3 and Q4 show that transgression events occurred contemporaneously with climate warming. Regional topographic variations, however, may have obscured the relationship between the paleoclimate fluctuations and the eustatic sea-level changes.
Relation: 39, pp.59-72
URI: http://ntour.ntou.edu.tw/handle/987654321/24899
Appears in Collections:[應用地球科學研究所] 期刊論文

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