内蒙古哈达门沟地区黑云母击象及其构造意义

Biotite percussion figures of metamorphic rocks of ural mountain group in Hadamengou area and its tectonic significance

黑云母击象构造是一种快速受力、脆性变形的产物。文章阐述了内蒙古哈达门沟地区新太古界乌拉山群变质岩中的黑云母发育的击象构造特征,认为黑云母击象明显受到退变质作用和混合岩化作用及韧性剪切作用,很可能是形成于新太古代末—古元古代初呼和浩特—包头断裂和临河—集宁断裂产生的地震作用中;新太古代岩石中黑云母击象的存在也证明了华北地块在新太古代末—古元古代初已经具备了较强的刚度,板块构造理论适用范围的最早时限很可能向前推移到新太古代。

The biotite percussion figures are the products of rapid stress and brittle deformation. Study on biotite percussion figures in Neo-archean metamorphic rocks of Ural mountain group shows that they are possibly formed in the initial earthquake caused by the Late Neoarchean to Early Proterozoie Hohhot- Baotou fault and Kanawha -Jining fault and are obviously transformed by retrometamorphism in the area. The existence of biotite percussion figures also shows that in the late Neoarchean to early Proterozoic peri- od the North China block already had sufficient rigidity and since then the movement of the earth＇s crust can be explained with the theory of plate tectonics.