新疆若羌县中坡山地区褶皱基底叠加褶皱构造解析

Structural analysis of the superposed folds in the folded basement of the Rouqiang Zhongposhan area,Xinjiang,China

新疆北山西段中坡山地区褶皱基底中元古界白湖群中普遍存在新月形、蘑菇形及线形紧闭褶皱,构造解析表明它们是由叠加褶皱形成的复杂露头干涉形式。区内第一期褶皱为NNW向、轴面东倾的同斜—平卧褶皱;第二期褶皱为NEE向紧闭直立-倒转背形向斜、向形背斜、背形背斜及向形向斜。该区叠加褶皱的形成与中元古代初始裂谷闭合及华力西晚期克拉通裂谷闭合密切相关。

There are folds formed by superposition of two period folds, in the folded basement of the Zhongposhan area, the western segment of the Beishan tectonic belt. The first period NNW folds are recumbent-isoelinal. The second period NEE folds are synform-anticline, antiform-sycline, antiformanticline and synform-sycline. The superposed folds found for the first time in the region are of great significance in the distribution of strata, the thickness of stratigraphy, the framework of structures and the evolution of tectonics. The form of superposed folds is closely related to the closing of the primary rift valley during the Middle Proterozoic and that of the craton rift valley during the Late Palaeozoic of the Beishan.