浙江长兴煤山剖面磁性地层学新研究

NEW MAGNETOSTRATIGRAPHIC RESULTS FROM MEISHAN SECTION, CHANGXING COUNTY, ZHEJIANG PROVINCE

通过对浙江长兴煤山剖面的高分辨率磁性地层学研究，得出以下结论：（１）浙江长兴煤山剖面可划分为５个正向极性亚带和４个反向极性亚带．其中，长兴阶下部为正向极性，上部为正反相间的混合极性；二叠－三叠系古生物界线处为反向极性；哥里斯巴赫阶底部为正向极性．（２）浙江长兴煤山剖面所在下扬子陆块二叠－三叠纪之交的古地磁偏角为２８．１°，古纬度为２０．１°Ｎ．这说明自二叠—三叠纪至今，该陆块曾经历过自南而北的纬向漂移和顺时针旋转运动．

From high resolution magnetostratigraphic study of the Meishan section of Changxing County, Zhejiang Province, the following conclusions are obtained: (1) The Meishan section can be divided into five normal polarity subzones and four reversed polarity subzones. The lower part of Changxing stage has normal polarity and the upper part has both normal and reversed polarities. At the paleobiostratigraphic boundary of the Permian-Triassic, the reversed polarity is found. At the bottom of Griesbachian normal polarity is also located. (2) During the Permian-Triassic in the lower Yangtze block where the Meishan section is located, the paleo_magnetic declination was 28.1°, and the paleolatitude was 20.1°N. This indicates that ever since the Permian-Triassic this block experienced northward and clockwise movement.