地质通报2017，Vol.36Issue(2)：238-250,13.
敦煌造山带岩石-构造组合特征及其构造环境
An analysis of the characteristics of the rock-structure association of the Dunhuang orogenic belt and their implications for tectonic setting
摘要
Abstract
Located between the Beishan orogenic belt in the north and the Qilian orogenic belt in the south, the Dunhuang region possesses a crucial tectonic position. However, the geotectonic attribution of this region has long been controversial. In this paper,the authors investigated the characteristics of the rock-structure association of the Sanweishan-Hongliuxia area in the Dunhuang region, which includes the Sanweishan-Northern Hongliuxia Area (SNHA) and the Southern Hongliuxia Area (SHA). The observation in the SNHA shows that the intensively sheared metasedimentary rocks are well exposed as matrix which enclose the blocks with differ-ent lithological types and ages, and the structural slices with different lithological types are tectonically superimposed upon each other. This rock-structure association with the"blocks-in-matrix"fabric integrally shows the typical characteristics of mélange. In the SHA, the metamorphic grade of the exposed rocks decreases southward, and the northern part of the SHA is dominated by the mica-quartz schist and felsic gneiss association, while the Late Carboniferous coal-bearing strata and carbonate succession regarded as being formed in a continental margin setting are exposed in the southern part of the SHA, which are overthrusted by the plagioclase am-phibolite nappe. In the SHA, the structural forms from north to south are from the north dipping intense shear zone through the du-plex to the imbricate thrust faults, accompanied by the southward decreasing deformation intensity. The characteristics of the rock-structure association of the SHA are consistent with those of the foreland fold-and-thrust belt. The authors thus hold that there exist two tectonic facies units, i.e., the Sanweishan-northern Hongliuxia mélange in the north and the Hongliuxia foreland fold-and-thrust belt in the south of the Dunhuang region. The collision process within the Dunhuang orogenic belt should occur after the Late Carboniferous period.关键词
敦煌造山带/岩石-构造组合/混杂带/前陆褶皱冲断带Key words
Dunhuang orogenic belt/rock-structure association/mélange/foreland fold-and-thrust belt分类
天文与地球科学引用本文复制引用
石梦岩,侯泉林,吴春明,王浩,陈泓旭..敦煌造山带岩石-构造组合特征及其构造环境[J].地质通报,2017,36(2):238-250,13.基金项目
中国科学院地质与地球物理研究所岩石圈演化国家重点实验室开放课题《敦煌造山带构造-热演化过程及其大地构造意义》(编号:开201605)和国家自然科学基金项目《敦煌地区变质作用演化及其大地构造意义》(批准号:41372199) （编号:开201605）
