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一、大陆大洋形成概念的分歧地球上的壳层有两层,上层为硅铝质称硅铝壳(或称花岗岩壳),它是构成大陆的主要物质,纵波速度5.5—6.2公里/秒,密度2.7克/立方厘米,褶皱部分厚约30公里,地台部分厚约24公里(如阿尔卑斯30公里、内华达28公里、俄罗斯地台20公里、南非地台24公里).下层为硅镁质称硅镁壳(或称玄武岩壳),地震纵波速度6.2—7.4公里/秒,密度2.8—3.0克/立方厘米,大陆部分的硅镁壳位于硅铝壳之下,地台处厚约16公里(如俄罗斯18公里、南非公里).褶皱带处厚约40公里(如阿尔卑斯36公里、内华达42公里),大洋部分缺硅铝壳,硅镁壳厚5—8公里,其本身又分二层,上层是从地球内新喷发出来的玄武岩,纵波速度5.12公里/秒,密度为2.55克/立方厘米;下层纵波速6.7公里/秒,密度2.86克/立方厘米,主要是基性岩、超基性岩、辉长岩,它是大陆下硅镁质层的连续体,由于上复硅铝壳的裂开而出露.由此可见大陆大洋的形成和地球圈层有关,又是地球圈层形成以后地壳构造运动的结果.
First, the concept of the formation of the mainland ocean divergence The Earth’s shell has two layers, the upper layer of silicon-aluminum called Si-Al shell (also known as granite shell), which is composed of the mainland’s main material, longitudinal wave velocity of 5.5-6.2 km / The density is 2.7 g / cm, the folds are about 30 km thick and the platform is about 24 km thick (eg 30 km in the Alps, 28 km in Nevada, 20 km in Russia and 24 km in South Africa) Silicon magnesium shell (or basalt shell), the seismic longitudinal wave velocity of 6.2-7.4 km / s, the density of 2.8-3.0 g / cubic centimeter, the mainland part of the silicon magnesium shell is located under the silicon aluminum shell, the platform at a thickness of about 16 km Such as Russia, 18 km, South Africa km.) Fold zone about 40 km thick (such as the Alps 36 km, Nevada 42 km), the ocean is partially lack of silicon aluminum shell, silicon magnesium shell 5-8 km thick, itself divided into two layers, The upper layer is a newly erupted basalt from the earth with a longitudinal wave velocity of 5.12 km / s and a density of 2.55 g / cm3; a longitudinal wave velocity of 6.7 km / s at a lower layer and a density of 2.86 g / cm3, Rocks, gabbro, it is the continuum of the magnesian layer under the mainland, due to the complex aluminum silicon shell Lu split out. This shows that mainland ocean planet formation and related spheres, is the result of tectonic movements of the Earth’s circle after the formation.