内蒙古固阳县席麻塔一带共轭剪切带的地质特征及形成机制

基金项目: 地质矿产部“内蒙古固阳地区三幅1∶5万联测”项目

GEOLOGY AND FORMATION MECHANISM OF CONJUGATE SHEAR ZONE IN XIMATA REGION, GUYANG COUNTY, INNER MONGOLIA

1.
Faculty of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083, China
2.
Regional Geological Surveying Team of Shanxi, Yuci 030600, China

摘要: 通过区调填图在内蒙古固阳县北山新太古代石英闪长岩和中元古代英云闪长岩中发现了韧性剪切带.通过野外调查、应变测量及显微构造、电子探针等方法研究表明, 该韧性剪切带为两组呈共轭组合型式产出, 形成机制与西伯利亚板块和华北板块相互挤压作用有关, 为在地球较深层次、在压扁环境下的简单剪切, 形成时代为中元古代末期, 变质相为绿片岩相.
- 共轭韧性剪切带 /
- 应变测量 /
- 内蒙古固阳县
Abstract: The regional geological mapping in Beishan, Guyang County, Inner Mongolia, indicates the presence of the ductile shear zones in the Neo-Archaean quartz diorite and the Meso-Proterozoic tonalities. The field investigation, strain measurement, indoor micro-structure and electronic probe show that this ductile shear zone occurs as two groups of conjugate combinatorial shear zones. The formation mechanism of this conjugate shear zone, a simple shear that occurred at the end of the Meso-Proterozoic in the falser environment, is related to the compression between the Siberia plate and the North China plate. The metamorphic facies of this conjugate shear zone is the greenschist facies.
- conjugate ductile shear zone /
- strain measurement /
- Guyang County, Inner Mongolia

图 1 研究区构造地质略图

1.第四系; 2.渐新统; 3.渣尔泰山群阿古鲁沟组一段; 4.渣尔泰山群增隆昌组二段; 5.渣尔泰山群增隆昌组一段; 6.渣尔泰山群书记沟组二段; 7.中元古代英云闪长岩; 8.新太古代石英闪长岩、闪长岩; 9.不整合; 10.韧性剪切带剪切方向; 11.韧性剪切带产状; 12.逆断层; 13.剪切带分带编号; 14.新元古代闪长玢岩脉

Fig. 1. Structural sketch map of study area

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图 2 贵城壕—车铺渠构造剖面

1.第四系; 2.石英闪长岩; 3.片理化带; 4.韧性剪切带; 5.闪长玢岩脉

Fig. 2. Guichenghao-Chepuqu structural section

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图 3 付林图解

a.NW带; b.EW带

Fig. 3. Flinn diagrams

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表 1 不同变形域中黑云母化学成分

Table 1. Chemical compositions of biotite in different deformation domains

表 2 EW和NW向韧性剪切带三维有限应变测量结果

Table 2. Measured results of 3-D finite strain in EW- and NW-trending conjugate ductile shear zones

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