地质科学2012，Vol.47Issue(3)：788-807,20.
川东褶皱带构造发育深度层次与变形样式
Tectonic levels and deformation patterns of the eastern Sichuan fold belt
徐汀滢 1季建清 1涂继耀 1刘志成1
作者信息
- 1. 北京大学地球与空间科学学院,造山带与地壳演化教育部重点实验室 北京100871
- 折叠
摘要
Abstract
Variation of structure and deformation patterns is much greater in the vertical dimension than it is in the horizontal dimension in the upper crust, eastern Sichuan fold belt features a stable geological evolution and strata occurrence since Late Paleozoic. However,the crust uplift since Later Cenozoic makes the strata and the basement with various depth exposed and distinct structural styles in different depth of the crust were displayed, providing ideal exposures for the study of tectonic levels. This paper proposes a new model to explain the formation of comb-like and trough-like folds in the eastern Sichuan fold belt through detailed structure analysis, combined with remote sensing images. Take Huaying Mountain and Qiyue Mountain as boundaries,the eastern Sichuan fold belt is divided into three superposed blocks. Block- Ⅰ is to the west of Huaying Mountain with the smallest(<2 km) deformation depth and no obvious deformation was seen. Block- Ⅱ lies between the Huaying Mountain and the Qiyue Mountain. The deformation style is steep structural foliations formed by NNE-trending shearing and the depth of deformation is 2 ~ 5 km. Block- Ⅲ is to the east of Qiyue Mountain. The deformation style is characterized by broad and gently-dipping folds with axis trending NE and the deformation depth is 4 - 6. 6 km. Different from the calm period from Paleozoic to Mesozoic, two stages of deformation-the early NNE-trending faults and the later NE-trending faults-were developed in the eastern Sichuan fold belt since late Cretaceous. The broad and gentle folds in Block- Ⅲ and the NNE-trending steep cleavages in Block- Ⅱ were developed under the same NW-SE compressive stress field. The later NE-trending faults caused the above three regions to be superposed as fault blocks. Due to the different uplift and exhumation rates of the blocks, the structural styles in different depth and deformation patterns in the three regions formed in the early deformation stage were displayed to the surface. This research bears significance for the innovation and studies of oil and gas traps, mineral deposit as well as other tectonics subjects.关键词
川东褶皱带/变形样式/深度层次/构造脱耦Key words
Eastern Sichuan fold belt/ Deformation patterns/ Tectonic levels/ Structural decoupling分类
天文与地球科学引用本文复制引用
徐汀滢,季建清,涂继耀,刘志成..川东褶皱带构造发育深度层次与变形样式[J].地质科学,2012,47(3):788-807,20.
