本文選題：大坪金礦床　切入點：控礦構(gòu)造特征　出處：《中國地質(zhì)大學(xué)(北京)》2017年碩士論文

【摘要】：大坪金礦床被視為哀牢山造山帶南段最典型的金礦床,礦體嚴(yán)格受成礦斷裂構(gòu)造控制。此區(qū)域構(gòu)造活動頻繁而強烈,具多期性、長期性和繼承性的特點。構(gòu)造不僅僅是控制著區(qū)內(nèi)的地層分布、巖體侵位,更重要的是對礦體的分布有著嚴(yán)格制約,使其成為控礦的主導(dǎo)因素。該礦床的成礦主要受自東向西的NNW向小寨——金平斷裂、NNW向小新街?jǐn)嗔押蚇W向三家河斷裂的聯(lián)合控制。以小新街?jǐn)嗔褳榻缦?以東的礦脈分為東礦化帶,研究主體為NW向V1-2-3礦脈;以西的礦脈分為西礦化帶,研究主體為NNW向V9-8-14礦脈。為研究礦脈的構(gòu)造運動學(xué)特征、控礦規(guī)律和變質(zhì)變形作用,本文主要對礦脈礦體形態(tài)、礦脈的產(chǎn)狀、構(gòu)造透鏡體和斷層角礫巖的形態(tài)和空間分布、階步和擦痕進行了詳細(xì)的觀察和研究,對韌性剪切帶中的石英進行了EBSD組構(gòu)分析,取得了如下成果和認(rèn)識:(1)對兩條礦脈的幾何學(xué)研究均表明,兩條礦脈在平面上呈串珠狀、豆莢狀分布,剖面上呈雁列狀和等距狀分布,向南東方向側(cè)伏。斷裂的膨脹部位是礦化富集的有利位置,構(gòu)成了厚大的金礦體,多個豆莢狀金礦體的斷續(xù)分布構(gòu)成了大坪金礦。金礦床的側(cè)伏方向與礦脈的斜深延伸方向一致。在空間上,分段富集、局部集中,分布間距相似,形成礦化富集中心和礦化富集帶。礦體厚度中心與礦體濃度中心相吻合。礦脈延伸指示成礦流體運移方向為南東——北西方向,礦化富集具有一定的側(cè)伏規(guī)律,由北西方向往南東方向深部側(cè)伏。(2)依據(jù)構(gòu)造透鏡體和斷層角礫的形態(tài)和空間分布,以及階步和擦痕的聯(lián)合分析,判斷含礦斷裂為左行剪切正斷層。(3)韌性剪切帶的石英EBSD組構(gòu)分析顯示,石英的變形溫度為低溫(400℃),反映本區(qū)經(jīng)歷了低溫變形變質(zhì)作用。(4)礦脈和斷層產(chǎn)狀投出的極射赤平投影圖表明,礦脈形成于左行壓扭性斷裂中。本文詳細(xì)討論了控礦構(gòu)造特征和礦體富集規(guī)律,這對深部成礦預(yù)測和擴大找礦遠(yuǎn)景具有重要意義。
[Abstract]:The Daping gold deposit is regarded as the most typical gold deposit in the southern section of the Ailaoshan orogenic belt, and the orebody is strictly controlled by the metallogenic fault structure.This area is characterized by frequent and intense tectonic activity, multi-period, long-term and inheritance.Structure not only controls the distribution of strata and emplacement of rock mass, but also strictly restricts the distribution of orebody, which makes it a dominant factor in ore control.The mineralization of the deposit is mainly controlled by the combination of the NNW-trending Xiaoxinjie fault and the NW-trending Sanjiahe fault from the NNW direction to the west of the deposit.The east vein is divided into east mineralization zone, the main body of study is NW direction V1-2-3 ore vein, the west vein is divided into west mineralized zone, the main body of study is NNW direction V9-8-14 ore vein.In order to study the tectonic kinematics characteristics, ore-controlling rules and metamorphic deformation of the vein, this paper mainly deals with the ore body shape, the occurrence of the vein, the shape and spatial distribution of the tectonic lens and fault breccia.The EBSD fabric analysis of quartz in the ductile shear zone has been carried out. The following results and the understanding of the geometry of the two veins have been obtained. The results show that the two veins are beaded on the plane.Pod-like distribution, the profile of geese and isometric distribution, south-east direction of lateral.The swelling part of the fault is a favorable position for mineralization and enrichment, forming a thick gold body, and the intermittent distribution of several pod-like gold bodies constitutes the Daping gold deposit.The lateral direction of the gold deposit is consistent with that of the diagonal extension of the vein.In space, the mineralization enrichment center and the mineralization enrichment zone are formed.The thickness center of the orebody coincides with the concentration center of the orebody.The ore-vein extension indicates that the direction of ore-forming fluid migration is in the direction of south-east-north-west, and the mineralization enrichment has a certain law of lateral potential. From the north to the west, the deep side of the ore-forming fluid is located in the direction of the south to the east) according to the shape and spatial distribution of the structural lens and the fault breccia.And the combined analysis of step and scratch shows that the ore-bearing fault is a left-lateral shear normal fault. The EBSD fabric analysis of the ductile shear zone shows that the ore-bearing fault is a ductile shear zone.The deformation temperature of quartz is 400 鈩，

本文編號：1709326