|Yu Lizhong,Xu Yu,Xu Shiyuan,Zheng Changsu.Paleoenvironmental implication of magnetic measurements on sediment cores from Taihu Lake, east China. J. Lake Sci.1995,7(2):141-150. DOI:10.18307/1995.0206
|关键词: 磁性测量 环境演变 太湖
|Paleoenvironmental implication of magnetic measurements on sediment cores from Taihu Lake, east China
Yu Lizhong1, Xu Yu1, Xu Shiyuan1, Zheng Changsu2
1.Department of Geography, East China Normal University, Shanghai 20006;2.Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008
|Taihu Lake is a large shallow lake on the southern deltaic plain of the Yangtze River An irLerdiscipline study is carried out on about two-meter-long sediment cores taken from this lake to retrieve high resolution information on Holocene environmental change in Taihu Lake region. Mineral magnetic measurement, as the precursor, has been made on three cores from vvest Taihu Lake and one core from east Taihu Lake, which is used for sediment stratigraphy, bulk lithological classification and core-core correlation. These results are set alongside those derived from geochemical, pollen and granulometric analysis to reconstruct the environmental seccesses recorded in the radiocarbon dated sediment column. For cores TM2, TM3 and Wl-6 from west Taihu Lake, three distinctive stratigraphic horizons have been identified on the basis of the magnetic measurements and they are correlated among the cores. These divisions are coincident with the variation of pollen assemblages, indicating different climatic periods In the Yangtze River Delta. It is suggested that the low part of these cores is the early Holocene sediments, when the climate became wanmar sea level rose and Taihu Lake appeared as several small separated lakes. There is no stable continued deposit at west Taihu since the large lake formed in mid-Holocene as the result of current erosion. At east Taihu, the sediment column recorded some detailed information on palaeoenvironmental changes, as it is a relatively small and closed bay. The study shows that rof magnetic parameters in core EU 1 are mainly resulted from changes in particle size constitution, implying the shifts of sedimentary environment in response to the climatic changes.
|Key words: Magnetic measurement environmental change Taihu Lake