关键词: 大地构造新探索, 岩片叠置系统, 热点砥柱状构造, 构造演化, 海南岛

Abstract:

Today there are such understandings as geosynclineplatform theory, diwa theory, islandarc theory and plate tectonics theory for Hainan Island tectonics. All these views, including mobilism of plate tectonics, are established on the basis of fixism of vertical movement, which believe that strata and rocks, especially granite was formed in situ, and accordingly established the multi stage and multi cycle of tectonic cycles or a geosyncline, platform and platform activation (or diwa) stage of development and evolution history, which embodies the mutual transformation of the activity and stability of the progressive process. When we reanalyze the existing data by using the new global dynamics theory, Choula tectonics forming fold belt and the orogenic model theory to rethink the tectonics of Hainan Island, these views are questionable. Through the analysis, it is found that, firstly all the PreCretaceous strata of Hainan Island have the unclear top and the contact relationship is unknown, often showing the fault contact. The establishment of the rock stratum does not accord with the relevant regulations, it is not able to establish the stratigraphic column in unification of the island according to the time sequence; it is also not able to establish geological tectonic cycle and geotectonic development stage according to the time sequence and integration relationship. Secondly, the most popular rock of Hainan Island is composed of the gneissic granite, which is obviously different from the continental fold belts (orogenic belts) composed of sedimentary metamorphic rocks. The gneissic granite with migmatization actually belongs to Archean TTG suite, which is not the intrusive rock emplaced in the PreCretaceous strata, but the sheet tectonics drewthrusted and pushed over the surface. Thirdly，according to the contact relationships of Island lithostratigraphy, it can be divided into five rocksheet structure systems: autochthonous system, quasi autochthonous system and three foreign systems, and then, the structural units are partitioned accordingly. Fourthly, Hainan Island, belonging to the firstorder tectonic units is the Tibetan Plateau vortexthrowing outthermonuclear reaction tectonic system. The secondary tectonic unit is the South China Sea and Hainan Island vortex structure zone, and the thirdlevel tectonic unit is Hainan Island vortexshear structure and interior pillar structure. Fifthly, the combined effects of the pillar shaped uplift and hot spot of basic volcano rocks of South China Sea is the fundamental reason of Hainan Island’s outcropping above the sea surface, belonging to autochthonous system. Sixthly, different rocksheet structure systems layered and piled up above nuclear columnhot spot tectonics according to the drawing out tectonics, which is the basic characteristic of the tectonic framework of Hainan Island. And finally the geotectonic history of Hainan Island can only begin from the late Mesozoic.

Key words: new exploration of geotectonic, overlaying system of rock sheet, hot spot nuclear column tectonics, tectonic evolution, Hainan Island