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本文根据布格重力异常资料计算了三江(金沙江、澜沧江、怒江)地区的地壳厚度。本区地壳厚度由北而南逐渐变薄,北部最厚达67公里,南部最薄为41公里;横断山中段,有向东西两侧变薄的趋势。根据本区地壳厚度的变化,划分出哀牢山、丽江——木里、建水——师宗三大地壳构造带;滇西、滇中、松(潘)甘(孜)、滇桂四大地壳构造区。文中对各区、带作了简要论述,并指出本文的地壳构造区与大地构造的二级构造单元具有一致性;而其中的地壳构造与三级大地构造单元又相吻合。本文从中生代以来海陆变迁关系,指出本区地壳厚度在新生代有剧烈的增加。并根据本区新生代区域性地壳褶皱运动,指出印度和欧亚两大板块在这一期间的碰撞,是本区新生代地壳形变的根本原因。
Based on the Bouguer gravity anomaly data, the crustal thickness of Sanjiang (Jinshajiang, Lancang and Nujiang) areas was calculated. The thickness of the crust in this area is gradually thinning from north to south, the thickest in the north reaches 67 km and the south is the thinnest in 41 km. In the middle section of Hengduan Mountains, there is a tendency that the east and west sides of the crust are thinner. According to the change of the crustal thickness in this area, the three crustal tectonic belts such as Ailao Mountain, Lijiang-Muli, Jianshui-Shizong are divided; the four crustal tectonic belts in Ailao, Dianzhong, Songpan, Gan, Crustal structure area. In this paper, the author briefly discusses each area and belt, and points out that there is consistency between the crustal tectonic zone and the tectonic unit of the secondary structure in the paper, and the crustal structure coincides with the tertiary tectonic unit. This article from the Mesozoic sea and land transition relations, pointed out that the crustal thickness in the area of the Cenozoic have increased dramatically. Based on the Cenozoic crustal fold movement in this area, the collision between India and Eurasia plates during this period is pointed out, which is the fundamental reason for the Cenozoic crustal deformation in this area.