• 责任者：Qin Huafeng (Institute of Geology and Geophysics ; Chinese Academy of Sciences ; Beijing 100029 ; China) ; Li Yongfei
• 刊名：Geological Bulletin of China
• 出版年：2013
• 卷期：32(2/3)
• 关键词：古地磁 ; paleomagnetism ; 内蒙古 ; Inner Mongolia
• 页码：p.388-398
• 图表：illus., 1 table, 47 refs.
• 分类号：0400
• issnNo：ISSN1671-2552
• isbnNo：CN11-4648/P

The closure time and spatial extent of the Palaeo-Asian Ocean remain topics of much controversy. Rock magnetic and palaeomagnetic studies of Permian sandstone from Taohaiyingzi area in Inner Mongolia indicate that the main magnetic mineral is magnetite. Anisotropy of magnetic susceptibility of 131 samples indicates that the directions of the principal axis K1 are parallel to the bedding planes and the minor axis K3 is perpendicular to them, which indicates a normal sedimentary fabric and confirms primary depositional nature of these sandstones. A total of 131 samples from 9 sites were subjected to thermal demagnetization. 72 samples from 8 sites yielded stable characteristic components. The overall average direction is D/I=349.8°/9.9°（A95=5.7°） and the corresponding palaeomagnetic pole is at 49.6°N and 316.0°E （A95=6.5°）. An elongation-inclination （E1） test indicates the existence of inclination shallowing. The corrected inclination is 24.9° and the corresponding palaeolafitude is 13.1°N. The palaeomagnefic pole after correction is 56.7°N and 318.7°E. From these results the authors infer that the study area was part of the North China Block in the late Permian, and this understanding provides a new framework for constraining the tectonic evolution of the Palaeo-Asian Ocean in the late Palaeozoic period.