东天山中段晚古生代面状剪切带形成机制与金成矿关系研究  

Structural controls on gold mineralization of Late Paleozoic horizontalshear in the central of Eastern Tianshan Mountains

作　　者：张忠义[1] 肖文进[1] 杨国龙[1] 高军辉[1] ZHANG Zhongyi;XIAO Wenjin;YANG Guolong;GAO Junhui(China Non-ferrous Metals Resource Geological Survey,Beijing,100012)

机构地区：[1]有色金属矿产地质调查中心,北京100012

出　　处：《地质论评》2023年第4期1489-1502,共14页Geological Review

基　　金：新疆地勘基金资助项目(编号:T14-1-LQ12);中国地质调查局地质调查二级项目(编号:DD20160011、DD20190011)的成果~~。

摘　　要：东天山晚古生代康古尔塔格构造—金矿带的中段南带开展构造控矿研究,为区域金矿定位预测与勘探提供依据。采用区域构造分析和构造解析方法,在雅满苏北部厘定出一类已发生变形改造的大型面状脆韧性—韧性剪切带,构造恢复表明,其形成于晚古生代造山早期向北的分层剪切或低角度逆冲剪切(S1//S0)作用,并作为区域金矿的一级控矿构造而成为俯冲带深源成矿流体向上运移成矿的主通道。在造山过程中递进变形的分层剪切或低角度逆冲剪切晚期、向南北向横向缩短转换阶段,伴随区域抬升和断褶作用,拆离剪切带分支断裂开始成生并向上突破,导致封闭在拆离带内运移的深源含矿流体以断层阀方式分流排泄,成矿流体沿分支断裂向上运移,在断裂上盘或上盘背斜枢纽处的低序次的断裂、破裂中聚集卸载,形成充填石英脉和交代蚀变岩型(造山型)金矿,并有时限为276.5±2.9Ma的石英闪长斑岩侵入产出;晚期褶皱、断裂等叠加构造则对矿床(体)破坏、改造及保存起了重要作用。To remain the geological underpinnings of location prognosis and exploration programs,the study on the structural controls of gold mineralization have been carry out in the southern kanggurtag structural gold belt of the central Eastern Tianshan.And a deformed flat-lying shear structure is distinguished by detailed regional structural analysis and structural examination in northern Yamansu.Removing later deformation effects suggests it resulted from a large-scale horizontal brittle ductile to ductile shear zone associated with northward layer-parallel shearing or low-angle thrust shearing(S1//S0)in the early stage of Late Paleozoic orogeny.The shear zone represents the first-order ore-controlling structure and provides a major fluid pathway for deeply sourced fluids escaping upward from subduction-zone.During the late stage of horizontal shearing,or transition from horizontal shearing to horizontal shortening resulted from two successive deformation phases in a progressive deformation event,the regional crust uplifted accompanied by the initiation of thrusting and folding.And a splay fault rising from the detachment zone had resulted in drainage and redistribution of deeply sourced fluids entrapped in detachment shear zones through fault-valve action.Ore-forming fluids upward migrate along fault,discharge and the gold deposited in secondary fracture networks to form vein-type to disseminated deposits in the hanging wall or hinge area of hanging wall anticline of fault.This is coincided with the emplacement of the quartz diorite porphyry bodies dated at 276.5±2.9 Ma.The later folding and faulting play an important role on the reconstruction and preservation to the gold ore.

关 键 词：东天山 面状剪切带 金矿 晚古生代 控矿机制 

分 类 号：P618.51[天文地球—矿床学]