晚太古宙大陆克拉通化作用评述

Review on the Continental Cratonization in the Archaean

晚太古宙大陆的克拉通化作用造成大量陆壳的生长、固结、稳定,并且使陆壳达到近于现代大陆的厚度与相当大的规模。主要证据表现为晚太古宙普遍发生以下地质事件:(1)广泛的麻粒岩相变质作用使陆壳内物质组分有规律迁移,造成下地壳难以再熔融而长久保持稳定,(2)花岗质岩类(TTG)大量侵入,成为大陆最主要的物质来源。(3)浅水沉积岩系普遍出现,指示成熟稳定的硅铝层上形成环境。(4)大规模不变形岩墙群侵位,证明克拉通已具备足够的刚性与稳定程度。

The continental cratonization in the late Archaean resulted in growth, con- solidation and stabilization of the cntinent in great volume, which was compar- able to the modern continent on thickness and scale. Following geological evevt, which is main evidence, happened in the late Archaean: (1). extensive metamorphism of granulite facies, giving rise to migration of some elements in the crust and stabilization of the lower crust over a long period of time; (2). emplacement of large volume of TTG, which became main material sources of the continent; (3). world-wide occurrence of shallow water sedimentary rocks formed in stable ensialic environment; (4). emplacement of undeformed mafic dyke swarms on large scale, which proves that the continental cratons were rig- id enough to be fractured brittlely.