星地碰撞的板块构造效应  

The Effect of the Impact of a Celestial Body with the Earth on the Plate Structure of the Crust

作　　者：刘广润[1] 张宏泰 唐辉明[3] 

机构地区：[1]华中科技大学水电学院,湖北武汉430074 [2]湖北省地质调查院,湖北武汉430030 [3]中国地质大学工程学院,湖北武汉430074

出　　处：《地球科学（中国地质大学学报）》2007年第3期381-388,共8页Earth Science-Journal of China University of Geosciences

摘　　要：板块构造是一种全球大地构造理论.它以洋底扩张、洋壳边缘俯冲及转换断层为主要构造活动形式,配以地幔对流为原动力,建立一套颇具魅力的板块构造机制理论,被受到广泛认同.但也存在一些重要问题,主要是其地幔对流理念难以令人信服和对海陆格局变迁问题没提出明确的动力机制.在阐明造成板块构造理论这两方面困难问题的主要理由之后,介绍了星地碰撞事件的存在状况及其动力作用,着重论述了大规模星地碰撞的动力作用强大,对全球地质构造活动都有重要影响,板块构造也难以避免;星地碰撞的强烈冲击作用,有能力造成洋底开裂或使大陆裂解.据此设想,可用“星地撞击成缝,减压诱发岩浆上侵”的模式,取代与地球内部层圈结构相抵触的“地幔对流”模式来解释洋底扩张;并以星地碰撞发生地点的随机变化性作为大规模海陆格局变迁的主控原因.如此,则可有助于上述板块构造理论中存在的两大难题的解决.Plate tectonics is a global structure theory. It takes the sea-floor spreading, oceanic crust subduction, and transform fault as main active forms and mantle convection as an original dynamic. Despite the fact that plate tectonic theory has been established with a popular acceptance, there are some important problems expecting to be resolved. The mainly reason is that its conception of mantle convection is not very convincing enough and it fails to explain the dynamic mechanism of sealand shift. After the illustration of the chief reasons causing these difficult problems on the plate tectonic theory, the instance and dynamic action of collision of a celestial body with the earth is introduced in the paper. It is emphasized that largescale collision plays such an important part in the global tectonic activity that the plate tectonics is no exception also and the intensive impact of a celestial body with the Earth is able to cause the crack of sea-floor or continent. So we can use the pattern of the crack caused by the collision of a celestial body with the Earth induces the uprising of magma by the subtraction of pressure （might simply be named ＂Impacted crack induce magma uprising pattern＂） to supplant the pattern of mantle convection which is featured with collision with the layer texture in Earth interior in order to explain the sea-floor spreading, and take the random variability of the spot of the collision as the main reason of large-scale sea-land shift. Thus it could be useful to solve the two main problems of the plate tectonic theory mentioned above.

关 键 词：星地碰撞 板块构造 洋底扩张 海陆变迁 

分 类 号：P541[天文地球—构造地质学]