摘要
将北方黄土研究中广泛应用的磁化率参数引入长江中下游下蜀黄土的研究，对镇江下蜀黄土古土壤序列进行了系统的质量磁化率采样测试。磁化率变化记录了中更世以来长江中下游地区经历了７～８次大的气候旋回变迁，与邻区风尘堆积及北方黄土高原具有一致性和相似性；下蜀黄土Ｓ２以来磁化率记录可与深海氧同位素记录进行细节上的详细对比，首次在下蜀黄土记录中发现了对应于ＭＩＳ中５ａ、５ｂ、５ｃ、５ｄ和５ｅ亚阶段的波动特征；对比揭示，近２０多万年以来，下蜀黄土堆积区对全球古气候变化有着积极的响应。
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.
出处
《中国沙漠》
CSCD
北大核心
2002年第1期27-32,共6页
Journal of Desert Research
基金
国家自然科学基金项目(49571071)
江苏省自然科学基金项目(BK97219)资助
