中国大陆及邻近海域航磁─大地构造解释及分区

AERIAL MAGNETIC ANOMALY-TECTONIC INTERPRETATIONS IN MAINLAND CONTINENTINENT AND THEIR ADJACENT SEAS OF CHINA

地表地质研究及中国航磁异常表明中国航磁大地构造具以下３种类型：沉积盖层区（深浅层结果反映正常构造层序）、构造盖层区（地表及浅层为外来推覆山系，与深部构成异常构造层序）和航磁异常地质历史时期各期沉积－构造事件叠加的记录。按郯庐断裂两侧华北、扬子地台区航磁－构造异常带的可比性，郯庐断裂总位移可达５００ｋｍ。中国大陆及邻近海域航磁－大地构造分区为：Ⅰ光蒙区、Ⅱ华北区、Ⅲ哈萨克斯坦区、Ⅳ塔里木区、Ⅴ青藏高原区、Ⅵ扬子区、Ⅶ华夏－台湾区。

The characteristics of aerial magnetic anomaly of mainland continent of China arc: positive anomaly area represent the high magnetic block of basement rocks, volcanic, granite rocks and other intrusions. Negative anomaly area are the reflections of sedimentary basins of PttPz 1 and deep ocean, and large fault zones. Magnetic anomaly reflect the physical characters of rocks above 201mn of the crust. Characteristics of aedal magnetics-tectonics of China. ( 1) Sediments covered areat where the deep structures shown by aedal anomaly is conespondence with the shallow and surfce sbuctures, such as Nomhem China Basin and Lower Yangtze Basin. (2) Tectonic covered area, a. Magnetic anomaly reflect sedimentary basins of PttPz 1 in depth and metsumorphic complexes and nappes, ttumst sheets in surface of the crust. Both stmctures are inconespondence, such as Kuluketague. b. Positive anomaly occurred in depth, and the nappe could covered directly over the basement rocks, such as Dabashan thnut zones. c. The Proterozoic and the early paleozoic basins in depth and many thrust nappes developed in surface, which commonly located in the front of mountain ranges, such as West Junggur Mountdn llanges, Nonhem Tianshan. (3) Aerial magnetic anomaly is a intergrated result of many orogenic events dudng geological time and mainly reject the Proterozoic and the early PaJeozoic basins, large fault zones, suiture zones and volcanic-magmadc zones since the late Paleozoic to present. Comparisons of aerial anomaly zones in both sides of Tancheng-Lujiang Faults show that the total left stake-slip displacements of tHs fault is more than 5001mn. Aerial magnetic anomaly-tectonic divisions in continental area of China are: Xingan-Mongolia Region, Nonhem China Region, Kazakhstan Region, Tarim Region, Tibet Plateau Region, Yangtze Region, and Huaxia-Taiwan Region.