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1.
尖峰坡锡矿床的围岩蚀变和矿化,具有和地层产状基本一致的层型分带规律。自下而上分为四带:A—黑云母花岗岩接触带,B—电气石、绢英、夕卡岩锡石金属硫化物带,C—夕卡岩—锡石磁铁矿金属硫化物带,D—透辉石、透闪石角岩弱矿化带。控制层型分带的条件是:①围岩化学性质的差异决定含矿热液的层型选择性交代,②各地层岩石的密度和孔隙率决定了层型分带的隔挡层与充填交代的空间,③层间滑动、层间剥离和层间裂隙,是含矿热液运移的通道及矿物沉淀的场所,④隐伏花岗岩是锡成矿的载体或热源。  相似文献   

2.
丹池成矿带泥盆系中发育的碳酸盐岩有利于交代,是形成富矿的重要条件。北西向紧密线型褶皱、断裂及其次级构造控制矿带的展布。黑云母花岗岩、斑状花岗岩与锡石—硫化物矿床关系密切,具有花岗岩凸起部位富锡、凹陷部位富铜和近铜远锡的矿化分带规律。  相似文献   

3.
四川会理岔河元古宙锡矿床的地质特征及成因探讨   总被引:1,自引:0,他引:1  
岔河锡矿床产于元古宙裂谷环境中,其形成与晋宁期的花岗质岩浆活动有关。矿化及有关的矽卡岩化蚀变为含矿热液对大理岩等围岩交代的产物,皆围绕岩体接触带分布,并呈现良好的分带。含矿热液主要来自花岗岩,它提供了主要的流体和锡。锡的迁移、富集主要经历了岩浆结晶分异及围岩蚀变两个过程,分异作用是锡在热液中逐渐富集的主要原田,而云英岩化等蚀变中“脱载”出来的锡难以造成锡矿化。  相似文献   

4.
个旧矿集区是滇东南最重要的锡铜多金属矿产地之一, 形成了云英岩-石英脉型矿化、与矽卡岩化有关的锡石-硫化物型矿化、蚀变基性火山-次火山岩型矿化和与断裂有关的各种脉型矿化构成的锡铜多金属成矿系统.根据区域构造-岩浆演化与锡铜多金属矿化系统的配置关系研究, 认为燕山晚期复式花岗岩体侵位进入以中三叠统为主的碳酸盐岩地层组成的褶皱带中, 锡铜等金属元素的成矿富集产生于花岗岩体与围岩接触带及其附近发生的接触交代和更远处发生的交代-充填过程, 成矿元素主要源自燕山期中下部地壳物质熔融形成的花岗岩浆和印支期裂谷环境中来自地幔的玄武岩-辉绿岩-辉长岩类, 多期脉动式的岩浆活动驱动了一个长效的热液系统, 这些要素共同构筑了这一巨量的金属矿集区.由此建立了个旧矿集区的区域成矿模型, 并对进一步寻找新的矿化类型提出了理论线索.   相似文献   

5.
东坡矿田位于湘东南加里东褶皱带与湘中、南印支褶皱带的衔接部位。断裂以NE组最发育,是控岩控矿的主要构造。地层主要为中上泥盆统,与矿化关系密切的是中上泥盆统的碳酸盐岩层。岩浆岩由老到新依次为花岗岩、花岗斑岩脉、辉绿玢岩脉。花岗岩可分为两期,均富Sn富F富碱质。锡多金属矿床主要分布于花岗岩与中上泥盆统地层的接触带上,矿床可分为云英岩化花岗岩型、夕卡岩型和石英脉型。其中的柿竹园—野鸡尾锡多金属矿床,不但规模大,而且集中了矿田内多种矿床类型于一体,由多阶段蚀变矿化迭加形成。  相似文献   

6.
大东山锡矿田矿化类型复杂,其中矽卡岩型锡矿规模大,可分含锡矽卡岩型和硫化物矽卡岩型。岩体区有脉状和面状云英岩产出,前者多具锡矿化,后者具钨矿化。燕山第四期花岗岩是锡(钨)成矿母岩,含SiO274.96%~75.28%,K2O+Na2O7.37%~8.54%,K2O>Na2O,与南岭地区钨锡成矿岩体具有相似的岩石化学特征。锡矿成因类型可划分为接触交代型、侵入岩浆热液型和风化矿床。根据成矿地质条件,认为在接触带寻找硫化物矽卡岩、硫化物型锡矿有较大前景,而在岩体区具有寻找云英岩型钨矿的潜力。  相似文献   

7.
一、地质概述与锡多金属成矿关系密切的雀儿山-格聂花岗岩带位于义敦碰撞带西部盖玉-定曲断裂带与德格-乡城断裂带之间。北北西向一级区域构造控制着含矿酸性岩浆岩带的展布,不同构造交接复合部位,次级褶皱及断裂对含矿岩体及矿化富集有明显的控制。该岩带北起邓柯南至乡?..  相似文献   

8.
在栗木矿田沟挂垒钻孔深部发现花岗岩体下部有厚度大于190m的二云母花岗岩,通过对二云母花岗岩以及上部白云母花岗岩的岩相学研究和分析对比,认为该区第二阶段的花岗岩上部为白云母花岗岩,在深部相变为二云母花岗岩,岩体中、上部的白云母花岗岩相主要是二云母花岗岩不同程度蚀变交代形成的,而不是岩浆就地重力分离结晶形成的,其蚀变程度相当于该区含矿花岗岩体矿化蚀变带下部的钾长石化带。无斑的白云母花岗岩相在钾长石化带中蚀变最强,最靠近主矿化蚀变带,有重要的找矿意义。各岩相的化学分析表明,W、Sn、Nb、Ta的矿化富集可能与岩浆气液分离作用或深部岩浆分异有关。  相似文献   

9.
1.构造蚀变岩观点的提出过去认为云龙锡矿床是混合花岗岩成因,即壳源重熔岩浆演化到交代岩浆阶段的产物,矿化富集在一套均质混合花岗岩中. 通过我们的研究,发现所谓的混合花岗岩实际上是一套构造蚀变岩.岩石遭受多次构造变动,发生了强烈的褶皱和破碎变质,具碎斑、残斑和溶蚀结构,条纹、条带和糜棱构造,普遍钠化、硅化、电气石化、绿泥石化及硫化物化,并有重结晶和强烈褪色.蚀变岩具对称分带,矿化往往在中心带,矿化强度与蚀变岩的宽度为正相关.控矿因素主要是构造和含矿热液加上有利的岩性,而不仅只是混合岩.  相似文献   

10.
文章在阐述长坡锡多金属矿床地质特征的基础上总结了矿化富集规律:①长坡锡多金属矿床由上部锡石硫化物矿体和下部夕卡岩型锌铜矿体组成,锡石-硫化物型矿体形态主要表现为大脉型、细脉带型以及似层状;夕卡岩型锌铜矿化主要沿赋矿岩石的裂隙充填、交代,形成细脉状、层状以及浸染状矿化,矿体分为2段,南西段为锡多金属硫化物矿,北东段为锌铜矿;②长坡锡多金属矿床具有明显的水平以及垂向分带特征,平面上从岩体中心向外依次为Zn,Cu→(W,Sb)→Sn,Zn→Sn多金属→(Pb,Zn,Ag);垂向上自下而上依次为Zn,Cu→Sn,Zn→Sn多金属→(Pb,Zn,Ag);③长坡锡多金属矿床矿化富集与构造关系密切,尤其是次级构造部位,矿化富集程度高。夕卡岩型锌铜矿富集受花岗岩体影响明显,靠近花岗岩体矿化增强。  相似文献   

11.
This study is concerned with formation of minerals containing Li, Be, Cb, Ta, W, Bi, and other elements. The distribution of 35 accessory minerals was examined in biotite granite massifs occupying an area of 10 km2 . These minerals formed during the late magmatic stage and mainly during the subsequent metasomatic processes, such as rnuscovitization, early albitization, greisenization, late albitization, and microclinization. Tantalum and columbium mineralization is associated with rocks intensely altered by the processes of alkaline metasomatism and reflects differentiation of rare earth's mineralization in marginal granite massifs. Minerals containing Be, W, Bi, Sn, and Mo were deposited during the acidic stage of metasomatism. The subsequent alkaline stage of metasomatism resulted in leaching of these elements and their redeposition outside the massif. The paper is of interest as a guide in prospecting for tantalum and columbium in granitic intrusions.--E. A. Alexandrov.  相似文献   

12.
交代作用在自然界十分普遍。它与内生、变质成矿作用关系尤为密切,许多矿床主要以交代方式形成,常伴生广泛和强烈的围岩蚀变现象,形成各类交代岩。这些交代岩石与矿体常形影相随,有着紧密的时空成因联系。研究交代岩的类型、矿物共生组合、分带性及其含矿性,不但能揭示矿床形成的物理化学条件和成岩成矿机理,而且还可以为预测隐伏矿体提供重要找矿标志。  相似文献   

13.
Wall-rock metasomatites of the Kara gold deposit, a high-temperature medium-depth pneumatolytic-hydrothermal formation, have been studied. Gold mineralization is associated with the intrusion of granitoids of the Kara-Chacha massif (J3) and dikes of alkaline rocks (J3-K1), which include hybrid porphyries, “grorudites”, etc. They are characterized by telescoping of ores, expressed best of all on joints of ore-bearing sites.The origin of the Kara-Chacha massif (Amudzhikan-Sretensk complex) is connected with pre-ore areal propylitization. The propylites demonstrate a zonal pattern relative to the massif and ore veins. A composite metasomatic column of propylitized rocks has been compiled.The thickness of intensely altered wall rocks does not exceed 1.5–2.0 m and the structure of these zones is very heterogeneous. Syn-ore metasomatites are found in propylitized rocks. The major factor of syn-ore alteration of host rocks is the active behavior of alkaline elements. Albitization, silicification (in separate sites), tourmaline and pyrite alteration occur at the early quartz-pyrite-tourmaline stage of mineralization. Sodium is supplied at this stage. During the next quartz-actinolite-magnetite stage sodium and potassium are active. The host rocks demonstrate albitization, feldspar alteration, silicification, actinolitization, biotite alteration, and magnetite impregnation. Aegirine in veins is accompanied by occurrence of aegirine, alkaline amphibole, green biotite and, locally, quartz in host rocks. Potassium becomes more significant later, reaching the maximum activity at the quartz-sulfide stage. The development of quartz-arsenopyrite assemblage was accompanied by K-feldspatization, sericitization of host rocks, formation of green and tan biotites, and arsenopyrite impregnation. The formation of K-feldspar, sericitization, silicification, and sulfide impregnation are associated with quartz-sulfide ore. The final quartz-carbonate-polymetallic stage is accompanied by silicification and carbonate alteration of host rocks. Potassium becomes increasingly more active from outer zones of metasomatic columns to inner ones. The gold contents tend to increase with the potassium contribution in zones of hydrothermal alterations.The propylite alteration and syn-ore changes become more intense veinward. It can indicate that hydrothermal solutions with dissolved minerals penetrated through the most reworked zones. However, hydrothermal solutions during propylite alteration and later syn-ore changes of host rocks not always penetrated through the same zones of weakness, such as tectonic dislocations, contacts of various rocks, etc. The rocks, comprising inner zones of the metasomatic column of propylites are quite often observed at a certain distance from veins and accompanied inner zones of metasomatic columns of later syn-ore metasomatites. They sometimes are not associated with ore veins. However, they are demonstrate later superimposed threads and separate impregnations of syn-ore minerals.Abundant telescoping of mineralization and inheritance of mineralization stages complicate the structure of zones with syn-ore metasomatites. In the sites with telescoped mineralization the metasomatites contain minerals intrinsic to all stages of mineralization found at the deposit.  相似文献   

14.
Summary The Habachtal emerald deposit, Hohe Tauern, is composed of blackwall sequences of the type: serpentinite — talc schist — ±chlorite schist or actinolite schist — biotite schist —albite gneiss and/or micaschist. 2 serpentinites, 33 blackwall rocks, 9 micaschists, 10 albite gneisses, and 5 aplitic gneisses were analyzed for major elements, and for Li, Be, Cr, Ni, Zn, Zr, Sn, in 36 samples also for Sc, Cu, Rb, Sr, Cs, Ba, W. The blackwall formation is due to a metasomatic exchange involving a transfer of Mg from the serpentinite to the silicic country rock, and of Si, Ca, K, and Al from the country rock to the serpentinite. Some of the trace elements were also mobile: Compared to serpentinite, Li and Be were enriched in all the blackwall rocks, and Sn and Cs in the actinolite, chlorite, and biotite schists; Sr was concentrated in the dolomite-bearing talc schists, and Zn, Rb, and Ba predominantly in the biotite schists.
Geochemie der Blackwall-Folgen in der Smaragd-Lagerstätte Habachtal, Hohe Tauern, Österreich. Teil 1: Darstellung der geochemischen Daten
Zusammenfassung Die Smaragd-Lagerstätte Habachtal, Hohe Tauern, besteht aus Blackwall-Folgen vom Typ: Serpentinit — Talkschiefer — ±Chloritschiefer oder Aktinolithschiefer — Biotitschiefer — Albitgneis und/oder Glimmerschiefer. Von 2 Serpentiniten, 33 Blackwall-Gesteinen, 9 Glimmerschiefern, 10 Albitgneisen und 5 Aplitgneisen wurden chemische Analysen der Hauptelemente und von Li, Be, Cr, Ni, Zn, Zr, Sn vorgelegt; 36 Proben wurden auch auf Sc, Cu, Rb, Sr, Cs, Ba und W analysiert. Die Blackwall-Bildung geht auf einen metasomatischen Austausch zurück, bei dem Mg aus dem Serpentinit ins Nebengestein, Si, Ca, K und Al aus dem Nebengestein in den Serpentinit transportiert wurden. Daneben waren auch einige Spurenelemente mobil: Im Vergleich zum Serpentinit wurden Li und Be in allen Blackwall-Gesteinen, Sn und Cs in den Aktinolith-, Chlorit- und Biotitschiefern angereichert; Sr wurde(n) in den dolomitführenden Talkschiefern, Zn, Rb und Ba hauptsächlich in den Biotitschiefern konzentriert.


With 5 Figures  相似文献   

15.
富锂氟含稀有矿化花岗质岩石的对比和成因思考   总被引:31,自引:5,他引:31  
Li-F花岗质岩石以超酸性、过铝、富含H2O、F、B、P等挥发性组分和富含Li、Rb、Cs、Be、Ta、Nb、Sn、W等亲石稀有金属元素为主要特征,以黄玉-锂云母-钠长石花岗岩为典型代表。从该类岩石地质产状的多样性和可对比性、空间分布的规律性、矿物岩石的结构构造、硅酸盐-熔体包裹体特征以及实验岩石学的研究成果等方面,综合论证该类岩石主要是从经过分异演化而形成的残余熔浆中直接结晶而在的;充分的分离结晶作用,是产生这种残余熔浆的主要机制;岩体的空间分带特征和各带之间的渐变过渡关系,为分离结晶作用的途径和演化方向提供了重要信息;熔体中挥发性组分的大量存在,是分离结晶作用能充分进行的关键因素;亲石稀有金属元素在流/熔配分中倾向于进入熔体相,是残余熔体中逐步富集这些稀有金属元素的主要原因;岩浆-热液过渡阶段出溶的流体相与已晶出的共存固相之间的相互作用,造成了广泛的交代蚀变现象;残余熔浆在不同地质和物理化学环境中的侵位、结晶和演化,造成了Li-F花岗质岩石在产状、结构构造和矿物组合等方面的多样性。  相似文献   

16.
华南陆块中生代受古特提斯构造域和滨太平洋构造域两大动力学体系控制,形成了独具特色的华南大花岗岩区和巨量稀有金属富集的成矿省.在印支期-燕山期动力体制转换的背景下,华南陆块内同一构造单元经历了不同世代、不同源区、多个类型岩浆作用相关的矿床成矿(亚)系列的叠加和演化,其叠加成矿机理是华南中生代大规模成矿作用研究的关键,其复...  相似文献   

17.
Two zoning patterns in tin deposits are proposed according to geochemical environments.
  1. Acidic zoning pattern is characteristic of tin deposits associated with sialic rocks and tin-bearing veins in carbonate rocks. Six zones may be recognized from the granite mass outwards: (1) Nb?Ta?(Li?Be?Mo), (2) Sn, (3) W?(Sn), (4) Cu?Pb?Zn?(Bi), (5) Sb?Hg, and (6) Au?Ag. This kind of zoning is related with the temperature difference involved in the deposition of various ore minerals in an acidic (or neutral) geochemical enviroment. From the granite outwards, the temperature decreases gradually with increasing distance from the heat source.
  2. Alkaline zoning pattern is typical of tin deposits occurring in calcareous and magnesian carbonate rocks. Three zones can be recognized from the granite mass outwards: (1) Cu?Zn?Bi, (2) Sn, and (3) Fe?Pb?Zn?Cu. A calcium-and magnesium-rich alkaline environment is responsible for this zoning pattern. In this case the normal sequence of mineral formation will be greatly changed owing to neutralization when an acidic ore-forming solution enters the alkaline environment.
Zoning structure in tin deposits is very complex and highly variable, depending on: (1) the geochemical environment in which the deposits are formed, (2) the type of shield beds, and (3) the character of ore-forming solutions. However, there are some known examples showing similar zoning patterns for the deposits that are similar in these three aspects.  相似文献   

18.
《International Geology Review》2012,54(10):1144-1153
The geochemical features of hydrothermal-pneumatolytic rare element deposits are discussed on the basis of a natural connection between high temperature metasomatism phenomena and concentration processes of some rare elements. Two kinds of metasomatic processes are most interesting from the view-point of rare elements (albitization and greisenization). Li and Rb are concentrated in zinnwaldite-bearingalbitized granites and greisens. Nb, Ta (in columbite, pyrochlore, microlite, hatchettolite), Zr (in malacone zyrtolite), Be (beryl) are concentrated in albitized and greisenized granites. The beryllium deposits are closely connected with greisens of different composition, and quartz-greisen veins. The fluorite-bearing metasomatic rocks among carbonate rocks are characterizedby accumulations of Be (chrysoberyl, phenacite, taateite, sianhualite), Li (Li - margarite), Sn (cassiterite). The character of postmagmatic alterations of intrusive and wall rocks is a valuable indicator of the possibility of concentration of different rare elements.—Auth. English Summary.  相似文献   

19.
Precambrian and Early Palaeozoic submarine exhalative Sn and W deposits are most commonly present in thick deep water sequences comprising pelites, carbonate, calcsilicate and cherty rocks, mafic volcanics and quartz-tourmaline rocks. The exhalative deposits are commonly low grade and, in places, the sequence is transgressed by granites with economic Sn or W mineralisation. These thick deep water sequences as components of sinking trenches are more likely than most other rocks to undergo high grade metamorphism and anatexis. Thus elements such as Sn, W, B, F, Mo, Bi, Li, Be and base metals associated with the exhalites rapidly partition into the anatectic melt, lower the liquidus and solidus, and are concentrated in the late stage aqueous fluids and residual melt fractions to form Sn or W deposits associated with highly fractionated granitic rocks.  相似文献   

20.
Pb-Zn-Ag-bearing M anganoan Skarns of China   总被引:2,自引:0,他引:2  
Manganoan skarns consist of special Mn (Ca, Mg, Fe, Al) silicate metasomatic minerals and are usually associated with Pb-Zn(Ag) mineralization. They occur chiefly along the lithologic contacts or faults and fractures of carbonate wall rocks distal from the intrusive contact zone, and are combined with Fe, Cu, W, Sn and Cu-bearing calcic or magnesian skarns occurring in the contact zones to constitute certain metasomatic zoning. Manganoan skarns are formed later than calcic or magnesian skarns. Their rock-forming temperatures are lower than those of calcic or magnesian skarns. The mineral assemblages of manganoan skarns occurring in different carbonate rocks (limestone or dolomite) are notably different.  相似文献   

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