Upper Jaramillo极性转换期间地球磁场变化特征

利用陕西渭南剖面黄土层位Ｌ１０的剩余磁性获得了ＵｐｐｅｒＪａｒａｍｉｌｌｏ极性转换期间地球磁场的记录。与地球磁场方向相联系的极性转换持续时间约３２００ａ。极性转换过程虚地磁极（ＶＧＰ）主要位于美洲大陆及其边缘，根据Ｒｏｃｈｅｔｔｅ模型。由极性转换前后地球磁场处于稳定极性状态时的平均方向模拟出的地磁极移曲线与实测曲线不同。这说明所得结果并不是由极性转换前后地球磁场平均效应引起的，应该是地球磁场变化的实际记录。本文收集了１９８９年之前中朝陆块自晚石炭世至第三纪期间的古地磁极数据。应用分类过滤方法选出可靠的古地磁极，建立了中朝陆块新的视极移曲线。通过中朝陆块与扬子陆块视极移曲线的比较，对前人提出的两个陆块会聚的几种模式进行了检验。本文提出的旋转模式，对研究两陆块的会聚过程是较合理的新观点。

PALEOMAGNETIC CONSTRAINTS ON THE CONVERGENCE OF THE SINO-KOREAN AND YANGTZE BLOCKS, CHINA

Paleomagnentic poles for the Sino-Korean block,ranging in age from Late Carboniferous to Tertiary,are compiled up to the end of 1989.A grading and filtering technique is applied to select reliable poles for establishing a new refined SinoKorean APW path.Different models related to convergence of the Sino-Korean and Yangtze blocks proposed in previous studies are tested through comparison of the APW paths for these two blocks.The paleomagnetic test confirms that the rotation model is the best one to constrain the process of convergence of these two blocks.