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1.
胶西北红布金矿地质特征及构造解析 总被引：3，自引：2，他引：3
胶西北红布金矿在焦家金矿田独具特色，它不同于一般意义上的构造蚀变岩型金矿，是发育在断裂带两侧花岗（闪长）质岩石中受密集节理裂隙带控制的细脉，网脉状金矿，构造解析表明红布金矿体主要形成于主断裂发生右行走滑的构造应力环境，基信压应力方位大致为SWW-NEE，主压应力轴近水平，含矿裂隙表现为张剪性质。 相似文献
2.
构造-流体-成矿作用的分形与混沌动力学 总被引：4，自引：2，他引：2
系统分析总结了构造活动与裂隙-脉体系统的分形生长,构造活动、流体作用及矿物沉淀之间的非线性反馈作用以及具分形结构与混沌特征的矿物沉淀和矿床的形成过程。以湘西金矿、水口山铅锌金多金属矿田等典型矿床为例,研究发现,水口山铅锌金多金属矿田地层及岩体内的元素含量分布均呈单分形关系,而断裂带内动性较强的Cu、Pb、Zn等成矿元素的元素具有双分形关系,产生了新的元素分布规律,指示断裂活动促进了成矿元素富集,湘西金矿石英脉是通过分形生长向着脉体长度-厚度分维值a值先减小(对应着脉体的膨胀)然后增大(对应着脉体的伸长)的趋势发展演化的,且该矿床各中段金品位空间变化序列均为非线性演化序列,其成矿流体的演化及成矿元素的沉淀富集成矿过程为混沌动力学过程。这些结果表明,构造-流体-成矿作用具有分形结构特征,并具体表现为断裂体系的分形分布,矿床的分形分布,裂隙-脉体系的分形分布和品位分布的分形变化等。成矿元素活化、迁移及沉淀的复杂动力学过程中,构造活动控制了裂隙-脉体系统的分形生长与矿床的就位,且存在于构造活动、流体作用及矿物沉淀之间的非线性反馈作用最终导致了具分形结构与混沌特征的矿物沉淀和矿床的形成。 相似文献
3.
震间期、同震期和震后期流体对断裂带物质的强度和运动性质起到重要作用。前人已识别出断裂带浅部区域流体对断层的弱化以及矿物沉淀导致的断层愈合,然而对于断裂带深部流体的研究鲜有报道。为深入了解孕震区流体行为以及地震成核过程中流体对断层的影响,本文以龙门山断裂带的映秀-北川断裂南段虹口乡八角庙村附近碎裂岩滑动带中石英和方解石脉为研究对象,通过对断裂带脉体的显微构造、碳氧同位素和主量元素含量等分析,开展地震相关脉体的特征结构、流体来源和矿物沉淀环境的研究。结果表明,碎裂岩主滑移带由颜色结构不同的三层断层泥和细小的方解石条带组成,在主滑动带边部和上盘碎裂岩中则分别发育了指示震间期、同震期和震后期三个阶段断层活动的脉体:(1)沿阶步生长的纤维状方解石脉和拉伸型柱状颗粒方解石脉;(2)断层泥楔入脉;(3)近等粒状方解石脉以及具有横向竞争生长结构的非等粒状方解石脉和石英脉。它们分别代表了震间期封闭的还原环境下的微滑动、同震外源高压流体注入以及震后开放的氧化环境至还原环境下的矿物沉淀。碳氧同位素结果表明主滑动带和碎裂岩方解石脉δ^(18)O V-PDB值为-20.5‰~-20.3‰,低于围岩碳酸钙胶结物,表明方解石脉具有大气水来源特征。方解石沉淀温度结合地温梯度表明方解石脉的形成深度大于4km,与碎裂岩形成深度及龙门山断裂带震源深度一致。该地区方解石脉和石英脉的研究深化了关于龙门山断裂带孕震区流体行为的理解,并且对进一步认识震间期、同震期和震后期断层的强度变化机制具有重要意义。 相似文献
4.
剪切带型金矿床中含金石英脉的一种可能成生机制 总被引：13，自引：1，他引：13
现在发现越来越多的产在太古代地块中的金矿床大多都是同构造剪切带型矿床，其容矿断裂是在区域构造应力作用下由液压致裂作用所形成，即含矿流体驱动裂纹的产生和扩展，并形成裂隙。而矿体中最重要的矿石类型──含金石英脉为同构造脉，即含矿流体紧随裂隙的张开而快速沉淀其中，形成含金脉体，并使裂隙愈合。含矿流体的不断补给和沉淀，使流体的压力发生周期性的波动，而这种波动的流体压力使＂裂隙－脉体＂系统发生周期性的裂开－愈合作用，由此形成了富金的多期多阶段的复式石英脉体。 相似文献
5.
河南小秦岭金矿田大湖金-钼矿床流体包裹体特征及矿床成因 总被引：22，自引：14，他引：8
河南灵宝大湖金-钼矿床位于小秦岭金矿田,属典型的断控脉状矿床。成矿过程经历3个阶段：早阶段为黄铁矿-石英脉,遭受变形、破碎,应形成于挤压或压剪过程;中阶段为细粒的辉钼矿-黄铁矿-石英网脉,贯入到早阶段黄铁矿或石英矿物的裂隙（可呈共轭状）,应形成于剪切环境;晚阶段石英-碳酸盐细脉具梳状构造,充填于张性或张扭性裂隙。即,流体成矿作用发生在赋矿断裂由挤压或压扭转向伸展或张扭性的过程中。旱阶段只发育CO2-H2O型流体包裹体;中阶段流体包裹体类型复杂,有纯CO2型、CO2-H2O型、H2O-NaCl型和含子晶包裹体,指示流体沸腾作用强烈;而晚阶段只发育水溶液包裹体。早、中、晚3个阶段的流体包裹体均一温度分别集中在400—500℃、290～470℃、220～260℃;估计的早、中阶段流体的最低捕获压力分别为138～331MPa和78～237MPa,对应于成矿深度分别为13．8km～11．0km和7．8km～8．0km。因此,成矿流体具中-高温、中-深成、低盐度、富CO2的特征,与中-深成造山型矿床一致。大湖金-钼矿床的成矿流体形成和演化及其成矿作用可利用CMF模式进行合理解释。 相似文献
6.
构造脉体作为构造流体的宏观标志记录了与构造运动有关的流体来源、形成环境条件和动力学等信息。大巴山构造带是一个典型的陆内造山带,发育了代表构造前、同构造期和构造后3期构造流体的方解石脉(V1、V2和V3)。本文在对构造后伸展背景下形成的方解石脉(V3)野外产状、几何特征和围岩力学性质统计分析基础上,通过其形成古应力场恢复和同位素地球化学分析,研究V3脉体形成环境条件及其流体来源。结果表明,V3脉体走向以NE SW向为主,脉体倾角较陡,大多近于直立,其形成的主应力轴σ1,σ2和σ3方位分别为67°∠76°、200°∠13°和293°∠10°,形成时的应力场为NW SE向拉张。V3脉体形成时流体压力pf<σ2<σ1,流体超压Δsi在92～167 MPa,形成最大深度为1.8～7.2 km。δ13C δ18O反映V3方解石脉形成与围岩碳酸盐岩脱CO2作用有关,V3方解石脉流体包裹体水的δD δ18O同位素分析表明其为盆地内部变质建造水向浅部迁移并有浅部表生水的参与。结合大巴山前陆构造广泛存在的异常高压流体,认为大巴山前陆在晚白垩世-古近纪时期处于伸展构造背景下,原来封存在深部的异常高压流体超压Δsi突破围岩形成裂缝,并上升到浅部与表生流体混合沉淀形成了V3脉体。 相似文献
7.
三甲金矿床位于胶东半岛东部的牟乳金矿带内岔河—三甲断裂的南端,其围岩主要为古老变质岩和昆嵛山花岗岩,为含金石英脉型金矿。本文通过对矿床控矿构造空间形态、活动期次、力学性质以及围岩蚀变等方面的研究,认为三甲金矿主要受控于主断裂,其内不同期次的次级断裂控制了矿体的空间产出位置;控矿断裂至少经历了三期应力改造,早期为压扭兼张扭性的右行剪切变形,中、晚期以张性裂隙为主-形成多金属硫化物石英脉,后期为压扭性裂隙内部充填形成石英+碳酸盐+多金属硫化物。进而总结了矿体在断裂带中分布的规律性。深部地球化学研究表明,三甲金矿的矿石类型、矿石矿物组合具有垂向分带的特征,矿物组合逆向分带与地球化学原生晕所指示的深部成矿叠加相一致。结合矿体在断裂中分布的规律以及原生晕特点,推断三甲金矿在-506m标高以下尚有成矿富集段的存在,此次研究为深部找矿提供了重要的依据。 相似文献
8.
双王金矿床是秦岭地区大型的危机矿山之一,找矿工作是当务之急,但其成因类型特殊,人们对其成矿构造的演化过程和控矿机制尚存在争议.以该矿床KT5矿体为例,研究了角砾岩体、断裂裂隙和金品位的空间分布关系,并结合趋势面分析,探讨了金矿化富集规律及其对成矿构造的指示意义.矿床地质特征及对矿区内基性岩墙的测年结果表明其成矿时代为印支期.在印支期秦岭造山过程中的NS向主压应力背景下,成矿断裂早期右行斜向剪切作用奠定了角砾岩带的雏形;断裂中期活动引发的地震及伴生液压致裂作用,使矿区内形成了角砾岩主体和断裂裂隙系统,主成矿阶段角砾岩化作用减弱,断裂裂隙持续发育,并作为流体运移和成矿的主要通道和有利部位,使金的矿化富集呈面状展布,断裂裂隙带的产状变化是金沉淀的重要影响因素;晚期构造应力转换为近EW向拉伸,近NS向基性岩墙群侵位并受到成矿流体的改造. 相似文献
9.
石英脉型金矿是常见的金矿床类型.金主要以粒间金、裂隙金和包裹金3种形式赋存于石英、黄铁矿等金属硫化物中.目前了解此类金矿的成矿流体组成主要是通过石英中的流体包裹体成分的定量和定性分析结果,揭示矿床成因.但是野外和室内镜下的综合研究已证实,金矿的形成经历了若干个成矿阶段.每个阶段都有石英和金属硫化物形成,而石英要明显早于金属硫化物的结晶,同时金在硫化物中的存在形式多为包裹金和裂隙金,这至少说明金和硫化物同时结晶沉淀或金比硫化物更晚沉淀.因此,金运移沉淀结晶时的流体和石英结晶时的流体存在着明显的时间差,金矿化与黄铁矿等金属硫化物有着密切的联系.研究金属硫化物中的流体包裹体来反映主成矿阶段的成矿流体物质来源,比研究石英中的流体包裹体更具有实际的意义. 相似文献
10.
东秦岭上宫金矿流体成矿作用:矿床地质和包裹体研究 总被引：22，自引：8，他引：22
上宫金矿产于东秦岭熊耳地体的熊耳群火山岩中，属于断控脉状造山型金矿床。上宫金矿赋矿构造由压剪向张剪演化，成矿过程经历了3个阶段：早阶段为黄铁矿一铁白云石一石英脉，脉体和矿物变形、破碎，形成于挤压或压剪环境；中阶段细粒多金属硫化物网脉贯入共轭节理或裂隙，没有遭受变形，形成于张剪环境；晚阶段具梳状构造的石英-碳酸盐细脉形成于伸展引张环境。流体包裹体组合从早阶段富CO2型，经中阶段富CO2型、贫CO2型和纯CO2型组合，向晚阶段贫CO2型演化。3个阶段的流体包裹体均-温度分别为380℃～320℃，300℃～220℃和200℃～120℃；早、中阶段的压力分别为285MPa～200MPa和160MPa～100MPa。中阶段流体离子(如SO4^2-，Cl^-，K^ )质量分数高，(K Na)／(Mg Ca)比值高，pH值高，Eh值低，属于碱性还原性质的过饱和流体，有利于多金属硫化物、碲化物和Au，Ag，Te等自然元素的快速沉淀。中阶段包裹体可见异相均一现象，具有较低的CO2／H2O比值，表明发生了以CO2逸失为特征的沸腾现象。东秦岭(含熊耳地体)三叠纪-早侏罗世地壳缩短、增厚、隆升，中侏罗世-早白垩世造山带挤压向伸展转折和隆升，白垩纪造山带伸展、断陷。这种区域构造演化的3阶段特征与上宫金矿含矿构造、矿石组构、成矿过程和包裹体组合的3阶段演化特征完全对应，指示上宫金矿形成于中生代陆陆碰撞造山过程，其成因可由碰撞造山成岩成矿与流体作用(CMF)模式合理解释。在中生代陆陆碰撞事件中，马超营断裂表现为倾向北的陆内俯冲带，俯冲板片变质脱水产生上宫金矿成矿流体，流体沿控矿断裂向浅部运移，在脆韧性过渡带发生沸腾和混合，导致成矿物质快速沉淀富集。 相似文献
11.
The Donalda gold deposit in the southern part of the Archean Abitibi greenstone belt consists
mainly of a subhorizontal gold-quartz vein perpendicular to subvertical shear zones. The 0.3e0.5 m thick
vein is characterized by vein-parallel banding structures indicating multiple episodes of fracture opening
and mineral precipitation. Measurement of the c-axis of primary growth quartz indicates that quartz preferentially
grew perpendicular to the fracture, suggesting open space filling and/or extensional nature of the
fracture. Measurement of the orientations of microfractures, veinlets and fluideinclusion planes (FIPs)
crosscutting primary growth quartz indicates that the vein minerals were subject to a vertical maximum
principal stress (s1), which is inconsistent with the subhorizontal s1 inferred from the regional stress field
with NeS shortening. This apparent discrepancy is explained by invoking episodic fluid pressure fluctuation
between supralithostatic and hydrostatic regimes accompanied by episodic opening and closing of the subhorizontal
fracture. When fluid pressure was higher than the lithostatic value, the fracture was opened and
primary growth minerals were precipitated, whereas when fluid pressure decreased toward the hydrostatic
value, the hanging wall of the fracture collapsed, causing collision of protruding primary growth minerals from both sides of the fracture and resulting in formation of vein-parallel deformation bands. The columns
where the two facing sides of the fracture collided were subject to higher-than-lithostatic stress due to the
bridging effect and reduced support surface area, explaining the development of vertical s1. This hypothesis
is consistent the fault-valve model, and explains the flipping of s1 without having to change the regional
stress field. 相似文献
12.
In Zhangbaling Tectonic Belt,two types of mineralization,auriferous quartz veins and alteration halos,can observed within many deposits.The pressure of metallogenesis of auriferous alteration halos is much higher than that of quartz vein,the temperatures of metallogeneses of these two types of orebodies are don't the same Geochemistry study indicates that both of them are micro-mesothermal deposits related to Yanshanian granites.The results of proton microprobe analysis of sulphides from the gold deposits in the area show that the "invisible" gold existed in sulphides is in the form of micro inclusions,and the concentration of "invisible" gold in sulphide minerals within quartz vein is poorer than that from alteration halos.Field observation shows that the structural modality of the fractures controlling the orebodies of auriferous quartz vein is different from that of the auriferous alteration zones.The fracture controlling the orebodies of auriferous alteration halos is compress-shear fracture,auriferous quartz vein is controlled by extensive fault.The alteration halos crosscut by auriferous quartz vein.The wallrocks of the former altered strongly and developed alteration zones well.The wallrocks of auriferous quartz vein altered slightly.The results of tectonogeochemical study shows that the concentration of associated metallogenesis elements and intensity of alteration are positively correlated with tectonic deformation strength for auriferous alteration halos.It indicates that it is probably a general character for micro-mesothermal gold deposits due to the multistages of metallogeneses took place.The tectonic environment is the most important fact determining the mechanism of fluid flow and precipitation of gold,and then the types of mineralization and modes of gold. 相似文献
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东准噶尔蒙西斑岩铜钼矿床脉体特征及其形成机制 总被引：5，自引：1，他引：4
蒙西斑岩铜钼矿床位于东准噶尔伊吾县琼河坝花岗岩北侧,以发育细脉、网脉状矿化为特征。脉体类型多样,包括石英脉、石英硫化物脉和硫化物脉等。根据脉体力学成因机制,其又可划分为水压破裂充填脉和构造破裂充填脉。构造破裂充填脉体按破裂形成的位错特征有正断与逆断两种。地表石英脉产状陡立,明显受断裂控制。脉体体积分数统计结果显示流体富集区呈向北缓倾的带状分布于深100～400m范围内,并与矿化富集带有较好的对应关系。脉体富集带内,脉体以共轭形式存在,一组为倾角较小的逆断破裂充填脉,另一组为倾角较大的正断破裂充填脉,他们可能为缓倾逆冲剪切带的次级破裂与充填脉,即富矿带内脉体是沿矿区低角度逆冲断裂次级破裂面充填的。矿区地表及深部(400m以下)脉体以陡立为主,矿化较弱。矿区流体的运移具先沿水压直立破裂往上运移,进入剪切带后沿剪切带次级破裂侧向和向上运移,并在剪切带中富集成矿。低温矿物组合脉体穿切高温矿物组合脉体的特征说明脉体形成过程矿区处于隆升构造环境,这对斑岩铜矿成矿有利。 相似文献
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16.
Ping'an Wang Hiroaki Kaneda Shijiang Ding Xiaowen Zhang Xiangjun Liao Faxian Dong Zhongjian Li Xiaochun Liu Yong Lai 《Resource Geology》2006,56(2):157-166
Abstract. The Baolun quartz vein type Au deposit, is located at the southwestern Hainan Island. It occurs next to a Triassic ilmenite-series/S-type syenogranite complex. A 40 Ar/39 Ar plateau age for muscovite from the master orebody is dated to be 219.4±0.6 Ma, suggesting that the gold deposit genetically related to the granite pluton. In the Baolun mining area, orebodies of auriferous quartz vein and wall rock alteration occur in NNW-striking fracture zones hosted by weakly metamorphosed turbidite of the Lower Silurian age. Eight fracture zones, 400∼1300 m long and 10∼30 m wide, have been identified. The five fracture zones of them form orebodies. The ores are mainly of quartz vein type. More than 20 orebodies in shapes of vein and lens of 195∼751 m in length and 0.20∼7.49 m in thickness are known, and 14 of them occur in the No. 1 vein belt. Silicification, sericitization and pyritization are closely related to the Au mineralization. The ores exhibit commonly 1.54∼29.48 g/t in Au grade, partially >98 g/t. The master orebody is 720 m long and 2.62 m thick in average, with 9.53∼29.27 g/t Au. Gold reserves of more than 70 t have been proven by geological exploration. More than 20 metallic minerals including native gold and sulfides such as pyrite, pyrrhotite, chalcopyrite, and others are identified to be formed in four ore-forming stages: (1) Au-coarse grain quartz stage, (2) Au-fine grained quartz stage, (3) Au-bismuthide-bismuth sulfosalt-sulfide-quartz stage, and (4) calcite-sulfide-quartz stage. The Au mineralization in this deposit occurred mainly in the first three stages. A variety of Bi- and Te-bearing minerals is closely associated with native gold suggesting that the mineralization may take place in a relatively high temperature. 相似文献
17.
四家寨金矿是康定杂岩内典型的石英脉-蚀变岩型金矿床,金矿（化）石英脉呈似层状,透镜状充填于构造破碎带中,硅化、黄铁矿化与金矿关系密切,脆-韧性剪切带是本区重要的找矿标志. 相似文献
18.
东沟构造蚀变岩-石英脉型金矿床,位于关子镇-元家坪和娘娘坝-舒家坝两条韧性剪切带与天子山和磨扇沟花岗岩体的夹持区,金矿化严格受其次级近EW向断裂控制,后期断裂构造对矿体具一定破坏作用。矿石类型地表以构造蚀变岩型为主,向深部过渡为石英脉型,褐铁矿、黄铁矿、毒砂是主要载金矿物。围岩蚀变以硅化、褐铁矿化、黄铁矿化、绢云母化为特征。中基性火山岩、韧脆性断裂构造、中酸性岩浆侵入“三位一体”是控制矿床形成的基本条件,近EW向断裂蚀变带及延伸部位是找矿有利地段。 相似文献
19.
粗榆一小铜矿地区属磐石一双阳接触带金及多金属成矿带的一部分，有良好的成矿地质环境，成矿物质来源于含金较高的石英闪长岩体和晚石炭纪石嘴子组地层等。热液矿化剂来源于岩浆分异晚期汽水热液和地表水的混合，北西向断裂构造及北东、东西向次级构造控制了地层岩浆岩的分布和矿化作用的演化，长期多期次的构造活动和脉岩的侵入使金铜等成矿元素活化富集，在有利的构造位置成矿。主要矿化类型有石英脉型和破碎带蚀变岩型。 相似文献
20.
《Chemical Geology》2003,193(3-4):273-293
The El Berrocal granite/U-bearing quartz vein (UQV) system has been studied as a natural analogue of a high-level radioactive waste repository. The main objective was to understand the geochemical behaviour of natural nuclides under different physicochemical conditions. Within this framework, the argillization processes related to fracturing and formation of the uranium–quartz vein were studied from a mineralogical and isotopic standpoint in order to establish their temperatures of formation and thus complete the geothermal history of the system. For this purpose, δ18O values were determined for pure mineral from the unaltered granite and quartz from the uranium–quartz vein, as well as for mixture samples from the hydrothermally altered granite (sericitised granite) and clayey samples from fracture fillings, including the clayey walls of the uranium–quartz vein. The isotopic signature of quartz from the uranium–quartz vein and the monophasic nature of its fluid inclusions led us to conclude that the isotopic signature of water in equilibrium with quartz was approximately in the range from −8.3‰ to −5.7‰ V-SMOV, its temperature of formation being around 85–120 °C. The δ18O values of pure sericite from the hydrothermally altered granite, calculated by means of the oxygen fraction molar method, indicate that its temperature of formation, in equilibrium with the aforementioned waters, is also in the range from 70 °C to approximately 120 °C. Clays from fracture fillings and clayey walls of the uranium–quartz vein are usually mixtures, in different proportions, of illite, approximately formed between 70 and 125 °C; two generations of kaolinite formed at approximately 90–130 °C and at around 25 °C, respectively; smectite, formed at ≤25 °C; and occasionally palygorskite, formed either between 30 and 45 °C or 19 and 32 °C, depending on the fractionation equation used. These data suggest that sericite from the hydrothermally altered granite, quartz from the uranium–quartz vein, illite and the first generation of kaolinite from the fracture fillings resulted from the same hydrothermal process affecting the El Berrocal granite in relation to fracturing. Under certain physicochemical conditions (T≈100 °C, pH≈8 and log [H4SiO4] between −4 and −3), illite and kaolinite can be paragenetic. As a result of weathering processes, smectite was formed from hydrothermal illite and inherited albite under alkaline weathering, while the second generation of kaolinite was formed from smectite, under acid conditions and close to the sulphide-rich uranium–quartz vein. Palygorskite is an occasional mineral formed probably either during the thermal tail of the above-described hydrothermal process or during weathering processes. In both cases, palygorskite must have formed from alkaline Si–Mg-rich solutions. Finally, these data and processes are discussed in terms of natural analogue processes, drawing some implications for the performance assessment of a deep geological radwaste repository (DGRR). 相似文献