甘肃阳山金矿区构造变形特征  

Tectonic Deformation Features of the Yangshan Gold Deposit in Gansu Province

作　　者：张龙 景永康 程贤达 张哲[1] 吴珺玮 王晓阳 Zhang Long;Jing Yongkang;Cheng Xianda;Zhang Zhe;Wu Junwei;Wang Xiaoyang(Xi’an Center of Mineral Resources Survey,CGS,Xi’an,Shaanxi,710100,China;School of Earth Science and Resources,Chang’an University,Xi’an,Shaanxi,710054,China;Center of Natural Resources Comprehensive Survey,CGS,Langfang,Hebei,065000,China)

机构地区：[1]中国地质调查局西安矿产资源调查中心,陕西西安710100 [2]长安大学地球科学与资源学院,陕西西安710054 [3]中国地质调查局廊坊自然资源综合调查中心,河北廊坊065000

出　　处：《新疆地质》2022年第3期434-440,共7页Xinjiang Geology

基　　金：甘肃省文县阳山矿带控矿构造及成矿规律研究专项研究;中国地质调查局地质调查项目(编号:DD20211551)联合资助。

摘　　要：甘肃阳山金矿位于西秦岭造山带南缘的勉略构造带内,区内构造-岩浆演化复杂,成矿地质条件优越。为查明复杂构造变形对阳山金矿成矿的控制和影响,本文对矿区内大量宏观及微观尺度构造变形进行测量统计,运用构造解析的原理方法,结合古应力差值估算及电子背散射衍射(EBSD)技术开展研究,得到以下结果:区内线理优选产状108°∠6°;紧闭褶皱枢纽优选产状110°∠18°;面理优势倾向为NNE向,平均产状45°∠50°;区域构造主应力方向为NNE向;韧-脆性显微构造变形指示区域主应力方向为18°~330°;石英动态重结晶法估算古应力差值为37.21~44.39 MPa;石英EBSD实验得到中低温组构模型(350℃~550℃);宏观及微观变形均指示由北向南的逆冲剪切指向。通过大量流体发育及韧性变形推测阳山金矿区构造变形具韧性通道流的特点,体现为一系列具韧-脆性变形特征的复式褶皱组合。Yangshan gold deposit is located in Mianlue tectonic belt in the southern margin of West Qinling orogenic belt,where the tectonic-magmatic events are complex and metallogenic conditions are superior.To find out the control and influence of complex deformations on gold mineralization,a large number of macro and micro tectonic deformations were measured,following the principles of structural analysis,combining analysis of paleostress and electron backscattered diffraction(EBSD)technology.Getting the following results:The preferred occurrence of lineation is 108°∠6°.The preferred orientation of closed fold hinge is 110°∠18°.The dominant tendency of foliation is NNE,with an average occurrence of 45°∠50°.The direction of regional tectonic principal stress is NNE.The direction of principal stress indicated by ductile-brittle microstructure deformations is between 18°and 330°.The paleostress difference estimated by quartz dynamic recrystallization method is 37.21~44.39 MPa.Quartz EBSD test get the fabric model of medium to low temperature(350℃~550℃).Both macro and micro deformations indicate the direction of thrust shear from north to south.The deformation characteristics of the north and south boundary of the thrusting nappe structure zone are compared and observed,and the structural deformation in the mining area is determined to be characterized by ductile channel flow.Based on the development of a large number of fluids and ductile deformations,it is inferred that the structural deformation of Yangshan gold deposit is characterized by ductile channel flow,which is manifested as a series of multiple fold combinations with ductile and brittle deformations.These results have positive meanings for clarifying the shape of ore body and guiding further mineral exploration.

关 键 词：西秦岭 逆冲推覆 韧-脆性变形 阳山金矿 

分 类 号：O614.123[理学—无机化学] P613[理学—化学]