关键词: 下蜀黄土, 磁化率, 环境记录, 镇江

Abstract: As a paleo-climatic proxy index, magnetic susceptibility (MS) parameter that has been widely used in loess studies of northern China, is applied in studies on the Xiashu loess in the south of lower reaches of the Yangtze River. On the basis of systematic sampling and measurement, the magnetic susceptibility features and their climatic implications of the Xiashu loess in Zhenjiang, Jiangsu province are analyzed in this paper. Magnetic susceptibility curve of the Xiashu loess is characterized by cycle, which records 7~8 large climatic cycles since Middle-Pleistocene in the lower reach of the Yangtze River and that is similar to the climatic change features disclosed by the aeolian deposition sequence in Anhui, Shandong and northern China. Magnetic susceptibility features indicate that the deposition section of the Xiashu loess is discontinuous and soaking by groundwater exerted an obvious influence on background value of the magnetic susceptibility. Magnetic susceptibility record of the Xiashu loess since S2 stratum coincides with marine isotope record since stage 7 perfectly. The change feature corresponding to MIS 5a-5b-5c-5d-5e is found in the Xiashu loess record for the first time in this paper, but the change details contain certain differences between MS record and MIS record. The comparison indicates that the area of the Xiashu loess deposition has given a sensitive response to globe paleo-climatic changes since about 200 a BP. On the other hand, the climate changes in some stages recorded by the Xiashu loess has regional characteristic obviously, which might be result of the dual effect of globe climate changes and East-Asia monsoon climate changes. The Xiashu loess section in Zhenjiang containing globe change information with high precision should be related to its geographic position, latitude location and landform conditions.

Key words: the Xiashu loess, magnetic susceptibility, environmental records, Zhenjiang