关键词: 地球起源, 圈层的形成, 陨击作用, 俯冲与碰撞, 大陆板块的生长, 大陆的破坏

Abstract:

The Earth in the early period (4.5 billion years before)was produced by the accumulation and accretion of the planetesimals, composed largely of the heavier elements, which had previously condensed from the solar nebula. The meteorite impact caused that the earth surface rocks against and crushed, evoked the supercritical fluid or magma uplift from the mantle, formed the violent volcanic eruption and let the volatile component concentrat on the solid earth surface, then let them gradually evolve to the hydrosphere and atmosphere. The oceanic crust was mainly formed by tholeiitic basalt, which was caused by the violent eruption of iron magnesium silicate rocks. The original continental cores were formed by gneiss domes, which may be also caused by the meteorite impact. The lithosphere plates were developed in 1.8～1.6 billion years ago. The strain rates of subductions between oceanic and continental plates or collision between continent and continent plates are all very low, which could be formed the partial fractures. However, the ductile deformation, metamorphism, magmatism and the injection and cooling caused the continents accretion continually. The Asian continental lithosphere plate was formed by 14 subductions or collisions, caused by 27 bigger ancient blocks and about hundreds small blocks from the 1.8 or 1.6 billion years ago to the recent. As to the continent destroyed, it may be caused by mantle plume uplift or giant meteorite impact.