前寒武纪地球动力学(Ⅴ):板块构造起源

Precambrian geodynamics(Ⅴ):Origin of plate tectonics

文中系统综述了板块构造启动时间的不同观点及其依据,并探讨了板块构造启动的三个必备条件：刚性岩石圈、俯冲作用、地幔对流循环的起源,进而探讨了前寒武纪俯冲作用、板块构造体制与现代俯冲作用、板块体制的差异。板块构造体制启动的三个缺一不可的条件：刚性、俯冲和地幔对流,直到27-21亿年期间才在全球不同地点同时满足。但现代板块构造体制起始的时间为10（或19）-8（或6）亿年,其标志性物质记录或识别标志依然是蛇绿岩建造、高压-超高压变质、岛弧型岩浆建造等。最后,系统描述了板块构造可能的启动机制和过程,为认识前板块构造和板块构造差异提供一个约束,也为推动地球动力学统一理论的思考和探索提供一些最新认识。

This paper summarizes different views and their corresponding evidence of the starting time of plate tectonics,and explores three requirements of starting plate tectonic system：rigid plate,subduction and mantle convection,and then further discusses the differences between the Precambrian subduction or plate tectonics regime and modern-style subduction or plate tectonics regime.The three requirements of starting plate tectonic system met at the same time until during 2.7-2.1Ga in different places around the world.But the modernstyle plate tectonic system and regime have a starting time of between 1.0（or 1.9）to 0.8（or 0.6）Ga;the remarked material records or identification markers are still ophiolite suites,HP-UHP metamorphic rocks,and arc magmatic rocks.At last,we describe possible starting mechanisms and processes of plate tectonics to provide a constraint for understanding the differences of pre-plate tectonics and plate tectonics,and to provide some latest insights for promoting thoughts and explorations of a unified theory of geodynamics as well.