阴山中生代地壳逆冲推覆与伸展变形作用

研究区属燕山—阴山中生代板内造山带西段的重要组成部分。依据变形特征和物质组成,可以分为北部构造活动带、中部隆起带和南部构造活动带3个不同的构造区。以中部隆起带为中心,在南北两侧的构造活动带中的构造样式和变形机制呈反向对称出现。逆冲构造和伸展构造在时间和空间上密切共生。在印支期—燕山早期地壳以逆冲挤压变形机制为主,形成了色尔腾山逆冲推覆体系和大青山逆冲推覆体系,而燕山晚期阶段在逆冲岩席上产生了背向伸展变形作用,形成了同构造的早白垩世呼和浩特—包头盆地和固阳盆地。

Mesozoic crustal overthrusting and extensional deformation in the Yinshan Mountains area

The study area is an important component part of the western segment of the Mesozoic Yan-shan-Yinshan intraplate orogenic belt.According to the deformation features and material composition,the area may be divided into the northern tectonically active zone,central uplift and northern tectonically ac-tive zone.With the central uplift as the center,the structural styles and deformation mechanisms in the tectonically active zones on the northern and southern sides are inversely symmetric.The thrust zones and extensional zones are closely associated in time and space.In the Indosinian and early Yanshanian the thrusting compressional deformation mechanism predominated,forming the Serteng Shan thrust nappe sys-tem and Daqingshan thrust nappe system;whereas in the late Yanshanian antithetic extensional deformation occurred in the thrust sheet,resulting in the formation of the Early Cretaceous syntectonic Hohhot-Baotou basin and Guyang basin.