摘要
本文根据地球重力位球谐函数系数和地幔对流的应力方程,选用(26～30)阶模式,计算了下扬子地区地幔流应力场,结合地质、地球物理资料综合分析,认为下扬子地区地幔流发散中心及其左、右旋扭应力组成的张扭应力轴,直观地反映了一条大陆裂谷带。裂谷带的西南段与郯庐裂谷南段的嘉山—宿松断裂带的位置基本重合;其北东段与苏北—南黄海盆地的位置也恰好一致。显然,嘉山—宿松段裂谷带与苏北—南黄海盆地是反映在同一条地幔流张扭应力轴上,应属同一条大陆裂谷带。这一论点为在下扬子地区开展基础地质理论研究以及寻找与裂谷带有关的矿产提供了根据。
Abstract
Based on the coefficients of spherical harmonics of the earch’s gravitational potential and the stress equations of the mantle convection pattern, using 26-30th. degreee pattern, the stress field of Yangtze has been calculated. Integrated analysis with geological and geophysical data was made. It is assumed that the divergent center of the mantle convection currents and its tense-shear stress axis consisting of sinistral and dextral rotation stress in the lower reach of Yangtze can directly perceive a continental rift zone is in existence. The southwestern part is as good as the Jiashan-Susong fracture zone for the southen part of the Tan-Lu rift, and its northwestern part is also as good as the position of North Jiangsu-South Huanghai Basin. It is evident that the Jiashan-Susong rift zone and North Jiangsu-South Huanghai Basin are reflected on the same tense-shear stress axis of the mantle convection and thus should be catagorized to the same continental rift zone. This argument furnishes a lot of substantial geological informations to us. They are deemed very helpful for the study of the basic geological theory and hunting for mineral resources with bearing of the rift zone as a matter of course.
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