青藏高原东北缘共和盆地第四纪磁性地层学研究

共和盆地第四纪剖面磁性地层学研究表明,该剖面包含了四个正极性段,三个负极性段,剖面底部地层年龄约为2.11Ma B.P.。结合剖面的沉积特征和已有的孢粉组合特征分析,可以确定该剖面记录了共和盆地2.11Ma B.P.以来的气候变化,且气候发生转型的主要时期依次为1.92 Ma B.P、1.75Ma B.P.、1.40Ma B.P.、1.02 Ma B.P.和0.87Ma B.P.。其主要原因可能是青藏高原强烈隆升远程效应的结果。共和盆地气候变化时间序列的建立为研究青藏高原隆升及环境效应提供有力证据。 

QUATERNARY MAGNETOSTRATIGRAPHY OF THE GONGHE BASIN ON THE NORTHEASTERN OF THE QINGHAI-TIBETAN PLATEAU

Study of the Quaternary magnetostratigraphy in the Gonghe basin on the northeastern margin of the Qinghai-Tibetan Plateau shows that four normal paleomagnetic polarity intervals and three reverse paleomagnetic polarity intervals are recorded in the Quaternary section and that the deposition of the section began at -2.11 MaB. P.. Based on the magnetostratigraphic study, combined with an analysis of the sedimentary characteristics and features of available Quaternary, sporopollen assemblages of the section, the authors think that the section records the paleoclimatic evolution in the basin since 2.11 MaB. P. and that the major epochs of paleoclimatic transition occurred at about 1.92, 1.75, 1.40, 1.02 and 0.87 MaB.P. respectively. This is mainly the result of the long-distance effect of the strong uplift of the Qinghai-Tibet Plateau. Therefore, the establishment of the time sequence of paleoclimatic changes in the Gonghe basin should have certain significance for the study of the uplift of the Qinghai- Tibetan Plateau and its environmental effect, as well as the development of the Yellow River.