论大陆裂谷的双模式地质特征

On Bimodal Geological Features of the Continental Rift

世界上一些典型的大陆裂谷均具有明显的双模式地质特征,即具有双模式火成岩,双层沉积结构,双模式变质作用,双模式成矿作用和双重构造作用。这是由控制大陆裂谷演化的热—动力过程所决定的,它反映了初期伴随拉张作用和地壳厚度的减薄,地壳发生断陷形成大陆裂谷,晚期伴随充填挤压,导致了裂谷地壳加厚,最终回返的裂谷演化历史,而双模式地质特征即是大陆裂谷早期和晚期这两个演化阶段的产物,是大陆裂谷最典型、最重要的鉴别标志。

Most of the continental rift in the world posses distinet bimodal geological features,i.e.they have bimodal magmatic rocks,double sedi- mentary structures,bimodal metamorphism,bimodal mineralization and double tectonism.All of these features are determined by thermodynamic process and make known that along with tension and thinning of crust in the initial stage the faulting was occurred to form continentai rift,and along with filling and compression in the later stage the crust of conti- nental rift was thickened,and thus the evolutional history was closed finally.The biomodal geological features are the resulting products deve- loped at two evolution stages of the continental rift,and are the most important and basic discriminant characteristics of the continental rift.