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1.
广东长坑金银矿床流体包裹体及同位素地球化学研究   总被引:9,自引:0,他引:9  
通过长坑金银矿床流体包裹体及氢氧硫碳同位素的研究,表明金矿体与银矿体在空间上虽存在分带性,但成矿的物质来源和成矿热液来源是相同的。金银矿床的形成,成矿温度为250℃,Logfo2为-38~-37,pH为4.0~5.6,硫化物的δ34S值为-6.6‰~8.8‰;成矿热液水的δ18O值和δD值分别为-7.8‰~9.0‰和-80‰~-43‰;金银矿石K-Ar年龄为133×106a~137×106a。因此,金银矿床的形成为燕山期岩浆活动提供热源,使大气降水在地层中循环淋滤,带出地层中成矿物质,并在容矿构造中沉淀形成矿床。  相似文献   

2.
横岭关铜矿床地球化学研究   总被引:1,自引:0,他引:1  
对横岭关铜矿床中稀土元素、同位素和矿物包裹体地球化学研究表明,矿床形成温度为350℃±30℃;压力为38×10~5Pa~240×10~5Pa;盐度为30wt%~42wt%;logfo_2为-30.41~-31.47;logfs_2为-5.4~-8;pH值为7.3;logfco_2为-2.49;铜的溶解度(logm_(Cu))为-5.87~-2.21。围岩的铅-铅同位素年龄为1775×10~6a,矿石的铅-铅同位素年龄为1845×10~6a;矿石硫同位素组成,δ~(34)S为-8.1‰~36.9‰,显示出硫同位素为非平衡特征;碳酸盐岩的碳同位素组成,δ~(13)C为-7.1‰~-2.6‰,δ~(13)C_(∑C)为-5.3‰;成矿流体的氢氧同位素组成具有变质热卤水的特点,认为该矿床属于变质热卤水成矿。  相似文献   

3.
在分析下庄铀矿田成矿地质背景的基础上,根据包体水氢、氧同位素组成和水-岩相互作用原理对该矿田成矿热液的水源进行了详细探讨。其结果表明,下庄铀成矿热液的氢、氧同位素组成δ18O=+6.90‰~-9.80‰(SMOW)、δD=-30‰~-85‰(SMOW)位于已发生氧漂移的大气降水同位素组成范围。水-岩同位素交换后,岩石的δ18O值明显降低,显示出与岩石相互作用的古地下水具有相当低的δ18O值。不同水-岩比值条件下同位素交换结果证明下庄成矿古水热系统具有比较充足的水源,大气降水与岩石交换后热液的δ18O计算(-8.26‰~+1.53‰)与成矿期热液的δ18O值(-6.54‰~+1.43‰)相吻合。证据表明下庄铀矿田成矿热液的水源主要来自大气降水。  相似文献   

4.
夏杖子金矿严格受构造破碎带控制,围岩蚀变主要为钾长石化、黄铁矿化、硅化和碳酸盐化。矿石中自然金有显微金和次显微金两种状态,金的成色为835~929;矿石包裹体成分主要以H2O为主,另含有CO2、K+、Na+、F-、Cl-和SO2-4等离子;矿石的稳定同位素组成:δ34S为-23.38‰~-14.47‰,δD为-91.7‰~73.1‰,δ18OH2O为5.68~6.25‰,206Pb/204Pb为16.411~16.615,207Pb/204Pb为15.228~15.256,208Pb/204Pb为36.268~36.356;矿石、脉岩和岩体具有相似的REE、K、Rb、Sr及微量元素地球化学特征。矿床中金的富集与成矿构造、围岩蚀变、矿化期次和矿石类型等多种因素有关,成矿作用发生于燕山晚期(105.4±7.2Ma),成矿热液主要为岩浆热液,成矿物质来源于硅铝壳中下部太古代结晶基底,矿床成因为中-低温热液金矿床。最后对矿床的找矿标志进行了总结,指出了找矿方向,认为夏杖子金矿具有较好的找矿远景,尤其是矿床深部  相似文献   

5.
东秦岭泥盆纪山阳-柞水成矿区内众多层控贱金属硫化物矿床含矿层中含有相当比例的电气石,这些电气石属于黑气石-镁电气石类质同象系列,一般Mg〉Fe,Na〉Ca(阳离子比较),明显的成分环带记录了主成矿期的海底(喷气)热液沉积成矿方式和随后的区域变质及热液叠加过程,在主成矿期形成的电气石的化学成分[FeO/(FeO+MgO)=-0.34-0.39]和硼同位素组成(δ^11B=-7.6‰ ̄-8.8‰)与海  相似文献   

6.
张家沟矿区存在两种不同类型的矿体,其地质特征不尽相同。通过对矿床流体包裹体和稳定同位素地球化学特征的研究表明,矿床的形成温度为140~300℃,成矿硫逸度lgfS2变化在-10.39~-15.70,lgfO2变化在-34.14~-45.16,pH值变化在4.64~6.15。早期成矿流体为一种低盐度高密度的热流体,随矿化作用的进行,成矿流体向弱酸性弱还原性方向演化。成矿作用以深部硫源的海底火山喷气热水沉积为主,后期以变质改造热液叠加为特征。层状矿体和脉状矿体为两次热事件形成不同矿化的产物。  相似文献   

7.
白云鄂博矿床稀土矿物稳定同位素特征及其意义   总被引:4,自引:0,他引:4  
方涛  裘愉卓 《矿床地质》1997,16(1):31-40
稀土元素是白云鄂博矿床最有特色的矿产。本文在详细讨论了稀土矿物氧、碳同位素制样方法的基础上,对矿床中晚期脉、白云石型矿石、萤石型矿石中的主要稀土矿物进行了系统的氧、碳同位素分析。其中,晚期脉中的氟碳酸盐矿物的碳、氧同位素值较低,具有幔源热液结晶的特点;白云岩型矿石中氟碳铈矿δ13C在-1.1‰~-3.4‰,δ18O在8.6‰~12.0‰;独居石δ18O在5.7‰~11.4‰,磷灰石δ18O在6.3‰~9.4‰;萤石型矿石中氟碳铈矿δ13C在-5.2‰~-5.8‰,δ18O在3.6‰~5.5‰;独居石δ18O在3.5‰~4.5‰。结合矿床地质特征分析,矿区萤石型矿石和晚期脉的形成可能与深源热液有关;而白云岩中的稀土矿化作用则表现出多源多期次的特点  相似文献   

8.
彭少梅 《广东地质》1996,11(2):59-65
通过对粤北大沟谷碎裂钠长石岩型金属矿床流体包裹体的研究表明,该矿床成矿流体是震旦纪变质地层在同推覆期的动力分异热液。矿床的形成经历了5个矿化阶段(D^13-D^53)金矿化主要发生在D^23和D^43。矿床形成温度200~300℃,压力37.4~4.3MPa,为中低温,中浅成矿化。成矿流体pH为6.76~7.14,为弱酸-弱碱环境,流体为Na-Ca-Mg(F)-Cl型,金可能以硫络合物形式迁移。  相似文献   

9.
东天山西滩浅成低温热液金矿床地质特征及成因分析   总被引:11,自引:1,他引:10  
西滩金矿床主要赋存在下石炭统阿奇山组的中酸性火山岩-火山碎屑岩中,典型蚀变矿物包括绢云母、冰长石、玉髓、绿泥石、浊沸石、水白云母等。流体包裹体和稳定同位素研究表明:δD=-119.4‰~-90.2‰,δ18OH2O=-12.74‰~-1.65‰,δ34S=0.11‰~2.31‰,成矿温度集中于150~200℃,含盐度很低(0.8‰~6.7‰),成矿压力为2.68×107~3.26×107Pa,pH值平均为6.7,由此推断成矿流体以大气降水为主,成矿物质具深源性,直接来自赋矿火山岩,属P·希尔德等分类中的冰长石-绢云母浅成低温热液金矿床  相似文献   

10.
河北洞子沟银(铜金)矿床成矿地质特征及成因探讨   总被引:14,自引:1,他引:13  
论述了洞子沟银(铜、金)矿床成矿地质背景和地质特征,成矿地质时代及矿床成因,并从硫同位素、氢氧同位素及包体成分、稀土元素等探讨了成矿物质来源,矿床硫同位素变化范围窄,δ34S=(-0.49~+2.8)×10-3,硫同位素组成以重硫型为主,接近陨石硫同位素组成。δ18OH2O=12.9×10-3,δDH2O=-73×10-3流体包裹体成分反映出成矿热液以岩浆来源为主,并混合了部分大气降水及雨水。提出本矿床是地洼区内的多因复成矿床。  相似文献   

11.
内蒙古阿右旗卡休他他铁金矿床属于夕卡岩-热液叠加型矿床。特定岩性、岩浆岩、构造是形成该种类型矿床的基本条件:辉长岩和石英闪长岩与围岩的接触带控制矿床的产出部位,岩体接触带的夕卡岩控制着铁、金矿体的分布范围,层间破碎带和构造裂隙带则控制着铁、金矿体的形态。铁矿化产于中基性岩体和围岩接触的夕卡岩带中,金矿体产在富铁矿体及其附近的夕卡岩中,金矿和铁矿是同一地质作用过程中不同阶段的产物,矿床可能形成于海西中期。  相似文献   

12.
作为战略性关键金属矿产,锂矿勘查与研究已成为当今矿产勘查和地学研究的热点。项目组2017年以来通过多次野外勘查、系统取样与室内化验分析,确认在新疆和田县白龙山锂多金属矿床东部的雪凤岭一带发现了雪凤岭、雪盆和双牙3处花岗伟晶岩型锂多金属矿床。雪凤岭锂矿床由3个含矿伟晶岩脉群共计47条锂多金属矿体组成,矿体长32~360 m,厚0.9~8 m,走向110°~120°,倾角49°~78°。对雪凤岭矿区伟晶岩脉群研究,发现含矿伟晶岩脉群‒含白云母伟晶岩脉群‒块体石英长石伟晶岩脉群‒含黑色电气石伟晶岩脉群‒块体石英长石伟晶岩脉群‒含白云母伟晶岩脉群‒含矿伟晶岩脉群具对称分带特征,进而在距雪凤岭1550 m南部的双牙山和雪盆沟发现较好的锂矿体,其中双牙锂矿床主矿体长850 m,厚12 m,出露最宽处近100 m;雪盆锂矿床3条锂矿体,长800~1200 m,厚4~8 m,向西合成一个矿体,厚12~20 m。各矿体Li2O品位0.6%~4.02%。伴生BeO品位0.04%~0.15%,Rb2O品位0.10%~0.23%,Nb2O5品位0.007%~0.047%,Ta2O5品位0.003%~0.046%。预测雪凤岭、雪盆、双牙3个矿床334资源量共计Li2O为7.1886×105 t,BeO为2.648×103 t,Rb2O为1.433×103 t,Nb2O5为3.387×103 t,Ta2O5为1.727×103 t,雪凤岭一带有望成为一个超大型锂多金属稀有金属矿产基地。  相似文献   

13.
云南白牛厂银多金属矿床成因   总被引:1,自引:0,他引:1  
对云南白牛厂超大型银多金属矿床的地质、地球化学特征及矿床形成的长期性及多阶段性的研究认为:白牛厂银多金属矿床是热水沉积—叠生成因矿床,早期呈现寒武纪的热水同生沉积成矿作用,晚期为燕山期花岗岩浆热液成矿作用。该矿床是热水沉积成矿作用与岩浆热液成矿作用叠加成矿的产物。  相似文献   

14.
云南大平掌铜多金属矿床硫、铅、氢、氧同位素地球化学   总被引:10,自引:0,他引:10  
对云南大平掌铜多金属火山岩型块状硫化物矿床的矿石矿物和火山岩围岩的S、Pb同位素及脉石矿物、硅 化岩、硅质岩等的H、O同位素地球化学特征进行了研究,认为矿床中大多数硫来源于热液对火山岩的淋滤,或直接 来源于火山喷气作用;矿石铅与火山岩铅属同一来源,且以富放射性成因铅为特征;成矿流体可能主要来源于深循环的海水与岩浆水的混合流体,而大气降水参与的可能性很小。  相似文献   

15.
加拿大萨斯喀彻温省索西(Southey)钾盐矿床特征及成因   总被引:1,自引:1,他引:0  
加拿大萨斯喀彻温省索西(Southey)钾盐矿床,主要赋存于中泥盆统的Elk Point(埃尔克波因特)群上部Prairie Evaporite(草原蒸发岩)组。钾盐矿层稳定,似水平状展布,埋深约1250~1550 m;钾盐矿物主要有钾石盐(KCl)和光卤石(KCl·Mg Cl2·6H2O),矿石品位高,w(K2O)可达11.17%~21.85%,是世界少有的高品质钾盐矿床。文章分别从构造位置、古地理条件、物源补给、沉积韵律和成矿过程等多个方面综合分析了索西钾盐矿床的成因。  相似文献   

16.
论凤山铜矿床的再生成因   总被引:3,自引:0,他引:3  
张立生 《矿产与地质》1992,6(6):431-439
凤山铜矿床产于中元古界昆阳群绿汗江组凤山段,其下伏为中元古代晚期的滇中裂陷槽中的狮山铜矿床。凤山铜矿床矿体呈脉状、巢状、囊状,切割围岩,形态产状受断裂构造及狮山段紫色层“刺穿体”的控制,是典型的后生矿床。矿石物质成分(以黄铜矿、斑铜矿为主)、黄铁矿的Co含量(0.6%)及Co/Ni比值(75.71)和硫化物的δ^34S值均继承了狮山铜矿床的特点;矿石具碎斑状、角砾状,细脉状和网脉状等后生矿石构造,凤山铜矿床黄铜矿、斑铜矿对各种波长入射光的反射率均高于狮山铜矿床黄铜矿、黄铜矿的Cu、Au、Ag含量高于狮山铜矿的黄铜矿,而S、As、Zn含量低于狮山矿的黄铜矿。基于上述特征,提出了凤山铜矿床的再生成矿模式。凤山铜矿床的成矿物质来自下伏的狮山铜矿床及狮山段紫色层细碧质火山角砾岩,经后期非含矿热液溶解而沿构造上升,而后在上覆地层的构造中沉淀、富集而形成再生矿床。  相似文献   

17.
The occurrence and the chemical compositions of ore minerals (especially the silver‐bearing minerals) and fluid inclusions of the El Zancudo mine in Colombia were investigated in order to analyze the genetic processes of the ore minerals and to examine the genesis of the deposit. The El Zancudo mine is a silver–gold deposit located in the western flank of the Central Cordillera in Antioquia Department. It consists mainly of banded ore veins hosted in greenschist and lesser disseminated ore in porphyritic rocks. The ore deposit is associated with extensive hydrothermally altered zones. The ores from the banded veins contain sphalerite, pyrite, arsenopyrite, galena, Ag‐bearing sulfosalts, Pb‐Sb sulfosalts, and minor chalcopyrite, electrum, and native silver. Electrum is included within sphalerite, pyrite, and arsenopyrite, and is also partially surrounded by pyrite, arsenopyrite, sphalerite, and tetrahedrite. Native silver is present in minor amounts as small grains in contact with Ag‐rich sulfosalts. Silver‐bearing sulfosalts are argentian tetrahedrite–freibergite solid solution, andorite, miargyrite, diaphorite, and owyheeite. Pb‐Sb sulfosalts are bournonite, jamesonite, and boulangerite. Two main crystallization stages are recognized, based on textural relations and mineral assemblages. The first‐stage assemblage includes sphalerite, pyrite, arsenopyrite, galena and electrum. The second stage is divided into two sub‐stages. The first sub‐stage commenced with the deposition and growth of sphalerite, pyrite, and arsenopyrite. These minerals are characterized by compositional growth banding, and seem to have crystallized continuously until the end of the second sub‐stage. Tetrahedrite, Pb‐Cu sulfosalts, Ag‐Sb sulfosalt, and Pb‐Ag‐Sb sulfosalts crystallized from the final part of the first sub‐stage and during the whole second sub‐stage. However, one Pb‐Ag‐Sb sulfosalt, diaphorite, was formed by a retrograde reaction between galena and miargyrite. The minimum and maximum genetic temperatures estimated from the FeS content of sphalerite coexisting with pyrite and the silver content of electrum are 300°C and 420°C, respectively. These estimated genetic temperatures are similar to, but slightly higher than the homogenization temperatures (235–350°C) of primary fluid inclusions in quartz. The presence of muscovite in the altered host rocks and gangue suggest that the pH of the hydrothermal solutions was close to neutral. Most of the sulfosalts in this deposit have previously been attributed as the products of epithermal mineralization. However, El Zancudo can be classified as a xenothermal deposit, in view of the low pressure and high temperature genetic conditions identified in the present study, based on the mineralogy of sulfosalts and the homogenization temperatures of the fluid inclusions.  相似文献   

18.
Abstract: The Shijuligou deposit was separated by an arcuate ductile shear zone cross the center of the deposit region, resulting in the difference between the southern and northern ore bodies. The lead (Pb) isotopic data of ores of the Shijuligou copper deposit have averages of 206Pb/204Pb, 207Pb/204Pb, and 208Pb/204Pb in 17.634, 15.444, and 37.312, respectively. It has been shown that ore-forming metals originated from intrusive and extrusive rocks in the upper part of ophiolites. The sulfur isotopic data of pyrite and chalcopyrite in the northern part change from +7.61‰ to +8.09‰ and +4.95‰ to +8.88‰ in the southern part. Isotopes of δ18O in the Shijuligou copper deposit are between +11.1‰ and +18.6‰, with the calculated δ18OH2O at +0.65‰. It is suggested that the mineralized fluid is a mixture of magma fluid, meteorological water, and seawater through circulating and leaching metals from the volcanic rocks. The zircon uranium-lead (U–Pb) dating of gabbro is 457.9±1.2 Ma, and the lower crossing age of the discordant and concordia curves of pyroxene spilite of zircon is 454±15 Ma. It is indicated that the Shijuligou deposit formed in a new ocean crust (ophiolite) of the back-arc basin in the late Ordovician. Mineralization should occur in the intermittence period after strong volcanic activity, and the age should be the late Ordovician. Moreover, the mineralization of ophiolite-hosted massive sulfide deposits in the ancient orogenic belt of the late Ordovician in the northern Qilian Mountains was controlled by the primary fault/fracture, with the forming of a metallogenic hydrothermal system by a mixture of volcanic magma fluid and seawater, which circularly leached the metallogenic metals from the volcanic rocks, resulting in their accumulation. The ore bodies were transformed with morphology and metallogenic elements. Jasperoid is an important sign for prospecting such deposits. There were many island arcs in the continent of China. This study provides evidence for understanding and exploration of ophiolite-hosted massive sulfide deposits in western China, especially in the area of northern Qilian Mountains.  相似文献   

19.
甘肃岷县寨上金钨矿床中钨矿特征及找矿标志   总被引:1,自引:0,他引:1  
寨上矿床属于以金为主、伴生钨的多金属矿床。目前已发现15条钨矿化体,其中主要的6条钨矿体均与金矿体相重合。寨上矿区9处异常中有7处Au、W异常相重合。Au、W元素相伴生存在,局部地区形成金、钨矿化体共生的局面。钨矿物主要为白钨矿,极少量黑钨矿。白钨矿也是重要的载金矿物,金与钨关系密切。矿体主要产于碳质板岩、泥质板岩、钙质板岩等较软弱岩性地层。矿脉受控于层间或顺层断裂破碎带。矿区的主要蚀变类型有硅化、黄铁矿化,其次为碳酸盐化、绢云母化。低阻高极化异常能较准确的反映矿化带和矿脉的延伸位置。钨的水系沉积物异常和土壤异常均呈带状低值异常特征,与已知矿带吻合较好。研究成果及勘查实践证明,在该金矿化(带)体中寻找钨矿化体是最简捷的方法。  相似文献   

20.
卡特里西铜锌矿是近年在新疆南部昆仑山一带发现的、规模最大的有色金属矿床.矿床产于下石炭统托库孜达坂群火山岩地层中,矿体分布明显受地层控制.含矿岩性为双峰式火山岩建造上部的灰绿色基性凝灰岩,矿体多呈平行层状、似层状、透镜状分布于灰岩中及灰岩与含碳粉砂岩的接触处.该矿为海相火山岩型铜矿.主成矿元素为铜、锌,伴生元素为银、铅、硫,共有14个矿体,其中Ⅵ、Ⅷ号矿体为主矿体,矿石品位较富,目前估算铜、锌资源量均超过中型.通过进一步的地质、地球化学、地球物理工作表明,矿床主矿体向深部仍有较大延深,预测该矿床规模有望达到大型.  相似文献   

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