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蒙西斑岩铜钼矿床成矿阶段及成矿元素统计分析意义 总被引：2，自引：0，他引：2
蒙西斑岩铜钼矿位于东准噶尔北塔山-纸房-琼河坝岛弧带东段琼河坝地区,属形成于断裂背景下的斑岩型矿床.脉状矿化是该矿床主要矿化类型,不同脉体有一定生成顺序.早期钾化阶段形成磁铁矿钾长石石英脉、硫化物钾长石石英脉、及高温阶段磁铁矿碳酸盐脉.进入硅化作用阶段后,形成磁铁矿石英脉、辉钼矿石英脉、黄铜矿黄铁矿石英脉、黄铁矿石英脉及少硫化物石英脉.成矿作用后期形成不含或少含硫化物的石英脉、碳酸盐脉.结合矿化蚀变带内地化元素的聚类分析、因子分析特征,初步将蒙西铜钼矿成矿作用分为早期构造挤压作用成矿期和岩浆热液作用成矿期.岩浆热液成矿期是该矿床的主要成矿时期,可细分为高温成矿阶段和中低温成矿阶段,分别对应形成Mo,Cu的富集矿化. 相似文献
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铜厂沟斑岩型钼铜矿床位于云南中甸地区斑岩成矿带的南端,形成于燕山晚期陆-陆碰撞至造山后伸展构造的转换阶段。文章通过对铜厂沟钼铜矿床蚀变分带特征和脉体穿切关系的详细研究,系统厘定了矿床蚀变类型及空间分布规律,查明了蚀变和脉体系统与矿化的关系。根据矿物组合、蚀变类型等因素,将分为A脉、B脉和D脉3大类,共16种不同的脉体类型。其中,A脉和B脉与成矿关系密切,对钼铜资源量贡献最大。早期的A脉,主要以钾长石化为主,矿化较弱;晚期形成的A脉多发育有黑云母化且与钾长石化蚀变叠加,矿化增强,以石英+黄铁矿+辉钼矿+黄铜矿±钾长石脉为主;B脉主要贡献于辉钼矿矿体的形成,是区内矿化的主要表现形式,且叠加于钾硅酸盐化,形成于钾硅酸盐化向石英-绢云母化的转变阶段;D脉中铜钼矿化明显减弱,属于矿化体外围的脉体,对矿体影响较小。因此,铜厂沟钼铜矿床蚀变分带规律在空间上表现为钾硅酸盐化（石英-钾长石-黑云母化）发育于斑岩体核部,向外依次是石英-绢云母化（石英-绢云母±黄铁矿化）,和青磐岩化（绿泥石-绿帘石-碳酸盐岩化）,对应的矿化组合分别为辉钼矿-白钨矿-黄铁矿、辉钼矿-黄铜矿-黄铁矿±白钨矿,以及外带的黄铜矿-黄铁矿-辉钼矿,显示出成矿元素由高温向低温变化的规律。铜厂沟斑岩型钼铜矿床的形成与区内燕山晚期伸展作用相伴的大规模构造-岩浆事件相关,源自深部的含矿热液在花岗质斑岩体内形成了脉状、网脉状的辉钼矿化,同时沿断裂带运移并扩散,于碳酸盐岩的接触带部位形成了矽卡岩型的铜钼矿化。因此,有利的构造环境、强烈的蚀变作用、多样的脉体类型导致铜厂沟大型斑岩型钼铜矿床最终形成。 相似文献
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西藏驱龙斑岩铜矿铜同位素研究 总被引：9，自引：1，他引：8
本文通过Cu的同位素组成示踪斑岩型铜矿床Cu的来源,探讨岩浆-热液过程中Cu同位素的分馏.选择驱龙矿区从早到晚的三期热液脉以及早期钾硅酸盐化蚀变同期的样品,挑选新鲜的黄铜矿,测定其Cu同位素组成.早期A脉:为不规则石英-钾长石脉、石英-硬石膏脉及黑云母脉,δ~(65)Cu的范围为-0.44‰～-0.09‰,集中在-0.44‰～-0.31‰,平均值-0.29‰;B脉,为石英+硬石膏+黄铜矿±辉钼矿±黄铁矿脉和绿帘石-石英脉,δ~(65)Cu的范围为-0.42‰～+0.14‰,集中在-0.25‰～-0.18‰,平均值-0.18‰;晚期D脉,为板状黄铜矿-黄铁矿及黄铁矿脉,δ~(65)Cu的范围为-0.27‰～+0.47‰,集中在-0.27‰～-0.05‰,平均值-0.02‰;早期钾硅酸盐蚀变带,δ~(65)Cu的范围为-0.47‰～-0. 1‰,平均值-0.29‰.矿区铜同位素组成基本同岩浆岩一致(Zhu et al.,2000,2002;Maréchal et al.,1999,2002),表明Cu主要来自斑岩岩浆.不同期次热液的Cu同位素具有明显的分馏,早期相对富集~(63)Cu,晚期相对亏损~(63)Cu,A脉与B脉的同位素组成的差异可能与岩浆-热液演化过程有关,D脉的同位素组成差异可能是大气降水大量混入的结果. 相似文献
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通过对纳日贡玛斑岩钼（铜）矿床的蚀变类型的详细研究,识别了矿床蚀变的3种主要类型：钾硅酸盐化、青磐岩化和长石分解蚀变.前二者为矿区早期形成的蚀变,长石分解蚀变形成于晚期.钾硅酸盐化蚀变主要以黑云母化、钾长石化为特征,青磐岩化以脉状绿泥石、绿帘石、方解石等蚀变矿物的发育为基本特征,长石分解蚀变则发育绢云母、高岭土、方解石、硬石膏等矿物.研究认为矿化与石英-辉钼矿±硬石膏±黄铜矿±黄铁矿脉、辉钼矿±黄铁矿±黄铜矿脉有较为密切的联系. 相似文献
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西藏多不杂富金斑岩铜矿床蚀变与脉体系统 总被引：12，自引：6，他引：6
多不杂富金斑岩铜矿床是班公湖_怒江成矿带第一个勘查评价出的大型斑岩铜矿床。文章在对矿区野外地质编录及室内镜下鉴定的基础上,对矿床蚀变与脉体系统进行了详细研究。结果表明,矿区发育典型斑岩铜矿蚀变系统,且分带性非常明显,从斑岩体内部向外具有钾硅酸盐化带(外缘叠加泥化蚀变与绢云母化蚀变)→绢英岩化带(大部分叠加有泥化蚀变)→青磐岩化带→角岩化带的分带特征。根据穿插关系、矿物组合及蚀变晕等特征可划分出21种脉体,早期形成的脉体包括在钾硅酸盐化带发育的磁铁矿细脉(M型脉共1种)、石英±钾长石±黑云母±磁铁矿±黄铜矿±黄铁矿脉(A型脉共8种)以及具有矿物组合分带特征的石英±磁铁矿±黑云母+钾长石+黄铜矿+黄铁矿脉(EB型脉共2种),中期形成的脉体包括主要在绢英岩化与泥化叠加带发育的石英±黄铜矿±黄铁矿±辉钼矿±石膏脉(B型脉共5种),晚期形成的脉体包括主要在青磐岩化带发育的石英±黄铁矿±黄铜矿±石膏±方解石脉(D型脉共5种),以A、B、D型脉最为发育。与矿化密切相关的蚀变带主要是钾硅酸盐化带、绢英岩化与泥化叠加带,与矿化密切相关的脉体主要为A型脉及B型脉。与国内外典型矿床相比,多不杂矿床蚀变模式及矿物组合与"二长岩"模式相似。多不杂矿床从内部的钾硅酸盐化带至外部的青磐岩化带均发育大量磁铁矿,且在青磐岩化带发育大量无矿石膏网脉,此是多不杂矿床的独有特色。 相似文献
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滇西宝兴厂斑岩铜钼金矿床成矿流体特征 总被引：1，自引：1，他引：0
宝兴厂斑岩铜钼金矿床是三江成矿带上与富碱斑岩有关的典型斑岩型矿床,产出于金沙江-哀牢山深大断裂带中部东侧。宝兴厂矿床铜、钼、金、铁等各类型矿化皆有发育,具有复杂的岩浆活动及热液演化。矿区岩浆岩主要为喜马拉雅期富碱复式岩体,包括正长斑岩、石英二长斑岩、花岗斑岩和斑状花岗岩等,具有多期次侵入特征。铜钼矿体主要分布于花岗斑岩和斑状花岗岩内部,铁金矿体主要分布于岩体内外接触带上,矿体呈脉状、透镜状或似层状。热液蚀变由内向外分带显著,依次为钾硅酸盐化(黑云母化)、绢云母化、青磐岩化(绿泥石-绿帘石化),局部黏土化。本文通过系统的野外观测、详细的岩芯编录以及全面的岩相学观察,依据矿物共生组合、矿化热液脉体穿切关系及蚀变特征,将宝兴厂矿床内主要矿化脉体分为3类:A脉、B脉及D脉。通过对3类脉体内石英中流体包裹体的显微测温工作和成矿流体物理化学条件计算,剖析了成矿流体演化特征,探讨了成矿作用过程与成因机理。A脉与钾长石化和黑云母化蚀变关系密切,多为不规则脉状,宽约1~5mm,矿物组合一般为石英±钾长石±黑云母±少量黄铜矿±少量黄铁矿。石英多呈他形细粒,少量黄铁矿、黄铜矿沿石英颗粒边界呈浸染状产出。脉体中常含有黑云母、钾长石,两侧常见钾长石蚀变晕。A脉中一般没有矿化。B脉宽约15~30mm,矿物组合一般为:石英±辉钼矿±黄铜矿±黄铁矿。靠近脉壁的石英多为他形细粒,向中心转变为长柱状垂直于脉壁对称生长。硫化物呈线状分布于脉体的中心或边缘。B脉一般没有蚀变,偶见少量的绿帘石化-绿泥石化。D脉与绿泥石化-绢云母化关系密切,脉体规则连续,脉体宽度变化范围大,为1~30mm。矿物组合一般为石英±绿泥石±黄铁矿±少量黄铜矿。石英数量较少,多呈半自形-他形粗粒,相对于B脉黄铁矿含量明显增多,黄铜矿含量减少,呈浸染状分布,脉体中钾长石、黑云母常蚀变为绢云母和绿泥石,脉体两侧常具有绿泥石-绢云母蚀变晕。A脉形成于成矿早阶段斑岩尚未固结时,其流体包裹体以含子晶(NaCl子晶为主)多相包裹体和富气相包裹体组合为特点,均一温度为364~550℃,盐度分别集中在45.64%~52.89%NaCleqv(含子晶多相包裹体)和3.3%~16.34%NaCleqv(气液两相包裹体)两个区间内,该阶段流体显示出沸腾、不混溶及发生相分离特征。根据A脉中5个含石盐子晶的包裹体压力估算图,得出宝兴厂矿床A脉中LVH相包裹体被捕获时的最低压力为50~145MPa,按地压梯度27MPa/km换算,A脉形成的深度最少1.8~5.4km。B脉形成于成矿主阶段,石英中发育含子晶多相包裹体(NaCl子晶)和富气相包裹体,均一温度为210~410℃,盐度集中在34.24%~52.04%NaCleqv和5.23%~13.99%NaCleqv两个区间内,该阶段成矿流体发生减压沸腾作用,使得Cu、Mo、Au大量沉淀,根据NaCl-H2O体系P-T相图压力估算,B脉的形成压力大约为15~48MPa,形成深度为0.56~1.78km。D脉形成于成矿晚阶段,石英以发育大量富液相包裹体为特征,均一温度为223~303℃,盐度集中在3.53%~11.71%NaCleqv范围内,该阶段成矿流体以中-低温、低盐度的岩浆热液与大气降水的混合流体为主,流体压力也降低到15MPa,形成深度不超过0.56km。宝兴厂矿床热液流体演化总体趋势为:由早阶段的高温、中-高盐度的岩浆热液向成矿晚阶段中-低温、低盐度的岩浆热液+大气降水混合流体转变。 相似文献
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滇中老街子Pb-Ag多金属矿床的成矿时代及成矿动力学背景探讨：来自硫化物Re-Os同位素证据 总被引：3，自引：0，他引：3
滇中老街子Pb-Ag多金属矿床位于红河-哀牢山新生代富碱斑岩带的中段,是与富碱火山-岩浆热液密切相关的典型矿床。首次在该矿床深部发现70m宽的高Cu-Mo异常黄铁矿化蚀变正长斑岩和黄铁矿-辉钼矿矿脉(2073中段3#穿脉),认为该矿床深部存在明显的富碱斑岩-岩浆热液型铜-钼矿化叠加成矿作用。本文选取深部坑道内的辉钼矿-黄铁矿脉、黄铁矿-方铅矿脉和高Cu-Mo异常黄铁矿化蚀变正长斑岩进行辉钼矿-黄铁矿Re-Os同位素成矿年代研究,获得了辉钼矿Re-Os等时线年龄33.71±0.29Ma和加权平均值年龄33.99±0.22Ma,说明滇中老街子斑岩型铜-钼成矿作用时代为渐新世,与Cu-Mo异常黄铁矿化蚀变正长斑岩成岩年龄一致。黄铁矿的初始Os比值(0.3049~1.5549)及其γOs值(140.5~1126)指示老街子Pb-Ag多金属矿床金属成矿物质主要来源于壳幔相互作用而形成的岩浆。老街子Pb-Ag多金属矿床成岩成矿年龄和区域上富碱斑岩-岩浆热液型多金属矿床成岩成矿年龄(30~40Ma)大致相当,表明印度板块与欧亚板块碰撞期后,构造应力场发生转变形成大规模区域左行走滑断裂系统,在稳定块体内部诱发壳幔过渡层发生部分熔融形成富碱岩浆和成矿流体,成矿流体沿着构造薄弱部位形成富碱斑岩-岩浆热液型多金属矿床。 相似文献
9.
新疆青河县新近发现哈腊苏铜矿床,正在进行的勘探证实具有大型铜储量前景。它位于阿尔泰东南缘,靠近额尔齐斯构造变形带。这个区域经历了古生代中期的洋-陆俯冲、古生代晚期的陆-陆碰撞以及其后的陆内活化等地质过程。铜成矿与哪种地质地质过程有关受人关注,矿床成因也存在斑岩型、热液脉型和火山岩型等不同认识。哈腊苏铜矿区主要出露中泥盆统基性火山岩(含苦橄岩)及侵入其中的不同时期含铜蚀变斑岩体,包括花岗闪长斑岩、斑状花岗岩、石英二长斑岩和石英闪长斑岩等,斑岩SiO_2质量分数为57.24%～65.45%,其中花岗闪长斑岩δ~(18)O_(V-SMOW)=7.9‰～8.6‰,ε_(Nd)(t)=7.3～8.5(接近于MORB值),(~(87)Sr/~(86)Sr)_t=0.70383～0.70410(接近原始地幔值),暗示岩浆起源于地幔或下地壳。矿区含铜蚀变斑岩全岩矿化(Cu 0.2%),矿体(Cu 0.3%以上)呈透镜状和不规则分枝脉状,产状与斑岩体相仿,95%以上矿体产于斑岩体内。围岩蚀变从矿体到斑岩再到基性火山岩围岩,发育钾长石黑云母化、黑云母绿泥石化、青磐岩化的分带,后期脉状线型钾长石化叠加于早期面状弥散型钾硅酸盐蚀变之上。没有次生硫化物富集现象,原生铜矿石出现细脉浸染型和脉状叠加型两种自然类型,前者以"黄铁矿+黄铜矿+辉钼矿"为典型金属矿物组合,后者呈在前者背景上的"石英+黄铁矿+黄铜矿"脉状叠加矿化。相对于前者,后者Cu、Au品位明显偏高(分别达到Cu 2.21%、Au 0.83 g/t)、微量和稀土元素总量降低,微量元素蛛网图和REE配分曲线更为平缓,Eu正异常更加显著。基性火山喷发、幔源岩浆侵入和多期矿化叠加是哈腊苏铜成矿的关键,早期斑岩型铜成矿基础上的后期构造热液矿化叠加显著。细脉浸染型铜矿石中共生黄铁矿-黄铜矿的硫同位素温度计指示斑岩型铜成矿温度为420～560℃。铜矿石硫化物δ~(34)S_(V-CDT)主体范围为-1‰～-4‰,矿石硫源自幔源斑岩体(有地层硫酸盐还原硫少量混入);黄铁矿~(206)Pb/~(204)Pb=18.052～18.461,~(207)Pb/~(204)Pb=15.501～15.606,~(208)Pb/~(204)Pb=37.813～39.335,与矿床所在区域喀拉通克岩浆Cu-Ni硫化物接近,成矿金属主体来自幔源斑岩;脉状矿化叠加型铜矿石中含铜硫化物石英脉晶出母液(δ~(18)O_(V-SMOW)=6.4‰～10.2‰,δD_(V-SMOW)=-89‰～-80‰)具有岩浆水的O、H同位素组成特点。通过成岩、成矿和热液蚀变的年代学研究获得:(1)含铜蚀变的斑状花岗岩(381.6±2.5)Ma和花岗闪长斑岩(371.8±9.6)Ma的U-Pb谐和年龄、细脉浸染型铜矿石中辉钼矿(376.9±2.2)Ma的Re-Os等时线年龄,是洋-陆俯冲期斑岩成岩成矿的年龄记录;(2)含铜蚀变石英二长斑岩(265.6±3.7)Ma的U-Pb谐和年龄和脉状叠加型铜矿石中钾长石(269.2±3.2)Ma的Ar-Ar坪年龄,是陆-陆碰撞晚期斑岩铜矿化蚀变的年龄记录;(3)含铜蚀变石英闪长斑岩(215.8±4.6)Ma的U-Pb谐和年龄和脉状叠加型铜矿石中钾长石(198.2±2.3)～(206.4±2.7)Ma的Ar-Ar坪年龄,是陆内构造岩浆活化期的年龄记录。多期构造-岩浆-热液矿化叠加作用是哈腊苏铜成矿的显著特征。该研究为认识中亚构造域斑岩铜矿床的多期叠加成矿作用特征积累了新资料。 相似文献
10.
为查明朱砂红矿床成矿流体来源及矿床蚀变-矿化流体演化过程,在已厘定的朱砂红矿床脉体类型基础之上,选取了不同蚀变阶段的蚀变矿物,进行了系统的H_O同位素测试。研究发现:早期A脉[无矿团块状石英脉(A1脉)、石英-钾长石脉(A3脉)]石英中包裹体δ18O值介于+6.0‰~+11.2‰,δD值介于-90‰~-101‰之间,在δ18O-δD图解中,A脉样品的H_O值组成整体位于去气作用后的残余岩浆水范围,表明引起早期钾硅酸盐化的流体性质为一套高温、高盐度岩浆热液;绿帘石-石英脉(B1脉)的δ18O值和δD值(+6.6‰和-101‰)显示青磐岩化蚀变形成与高温岩浆流体相分离后的低密度气相流体有关;而斑岩中的石英-黄铁矿-黄铜矿(B3脉)形成时,流体δ18O值(+4.1‰~+6.0‰)开始朝雨水线方向发生轻微的氧漂移,表明开始有少量大气降水的加入;晚期D脉形成时的成矿流体δ18O值(+2.8‰~+4.9‰)具有明显朝雨水线发生漂移的趋势,表明引起石英-绢云母化及泥化蚀变的成矿热液为岩浆热液和大气降水的混合流体。总之,朱砂红矿床钾硅酸盐化、青磐岩化蚀变,以及该蚀变阶段形成的A脉和早期B脉,均由岩浆热液作用引起,大气降水在钾硅酸盐化向长石分解蚀变转变的阶段开始进入蚀变-矿化系统,而长石分解蚀变为大气降水与岩浆热液共同作用的产物。 相似文献
11.
Akira Imai 《Resource Geology》2005,55(2):73-90
Abstract. Evolution of hydrothermal system from initial porphyry Cu mineralization to overlapping epithermal system at the Dizon porphyry Cu‐Au deposit in western central Luzon, Zambales, Philippines, is documented in terms of mineral paragen‐esis, fluid inclusion petrography and microthermometry, and sulfur isotope systematics. The paragenetic stages throughout the deposit are summarized as follows; 1) stockwork amethystic quartz veinlets associated with chalcopyrite, bornite, magnetite and Au enveloped by chlorite alteration overprinting biotite alteration, 2) stockwork quartz veinlets with chalcopyrite and pyrite associated with Au and chalcopyrite and pyrite stringers in sericite alteration, 3) stringer quartz veinlets associated with molybdenite in sericite alteration, and 4) WNW‐trending quartz veins associated with sphalerite and galena at deeper part, while enargite and stibnite at shallower levels associated with advanced argillic alteration. Chalcopyrite and bornite associated with magnetite in quartz veinlet stockwork (stage 1) have precipitated initially as intermediate solid solution (iss) and bornite solid solution (bnss), respectively. Fluid inclusions in the stockwork veinlet quartz consist of gas‐rich inclusions and polyphase inclusions. Halite in polyphase inclusions dissolves at temperatures ranging from 360d?C to >500d?C but liquid (brine) and gas (vapor) do not homogenize at <500d?C. The maximum pressure and minimum temperature during the deposition of iss and bnss with stockwork quartz veinlets are estimated to be 460 bars and 500d?C. Fluid inclusions in veinlet stockwork quartz enveloped in sericite alteration (stage 2) consist mainly of gas‐rich inclusions and polyphase inclusions. In addition to the possible presence of saturated NaCl crystals at the time of entrapment of fluid inclusions that exhibit the liquid‐vapor homogenization temperatures lower than the halite dissolution temperatures in some samples, wide range of temperatures of halite dissolution and liquid‐vapor homogenization of polyphase inclusions from 230d?C to >500d?C and from 270d?C to >500d?C, respectively, suggests heterogeneous entrapment of gaseous vapor and hypersaline brine. The minimum pressure and temperature are estimated to be about 25 bars and 245d?C. Fluid inclusions in veinlet quartz associated with molybdenite (stage 3) are dominated by gas‐rich inclusions accompanied with minor liquid‐rich inclusions that homogenize at temperatures between 350d?C and 490d?C. Fluid inclusions in vuggy veinlet quartz associated with stibnite (stage 4) consist mainly of gas‐rich inclusions with subordinate polyphase inclusions that do not homogenize below 500d?C. Fluid inclusions in veinlet quartz associated with galena and sphalerite (stage 4) are composed of liquid‐rich two‐phase inclusions, and they homogenize into liquid phase at temperatures ranging widely from 190d?C to 300d?C (suggesting boiling) and the salinity ranges from 1.0 wt% to 3.4 wt% NaCl equivalent. A pressure of about 15 bars is estimated for the dilute aqueous solution of 190d?C from which veinlet quartz associated with galena and sphalerite precipitated. In addition to a change in temperature‐pressure regime from lithostatic pressure during the deposition of iss and bnss with stockwork quartz veinlets to hydrostatic pressure during fracture‐controlled quartz veinlet associated with galena and sphalerite, a decrease in pressure is supposed to have occurred due to unroofing or removal of the overlying piles during the temperature decrease in the evolution of hydrothermal system. The majority of the sulfur isotopic composition of sulfides ranges from ±0 % to +5 %. Sulfur originated from an iso‐topically uniform and homogeneous source, and the mineralization occurred in a single hydrothermal system. 相似文献
12.
德兴铜厂斑岩铜(钼金)矿床蚀变-矿化系统流体演化:H-O同位素制约 总被引：2，自引：0，他引：2
江西铜厂斑岩铜(钼金)矿床是德兴斑岩矿集区最大的矿床.文章根据铜厂矿床发育的钾硅酸盐化、绢英岩化、青磐岩化蚀变组合特征,和已厘定的铜厂矿床脉体类型,选取代表不同蚀变矿化阶段的石英、黑云母、绢云母及绿泥石等,进行单矿物的H、O同位素测试.石英和黑云母单矿物O同位素,与石英、黑云母平衡流体的δ 18O 值和δD值联合示踪结果显示,铜厂矿床早期A脉(不规则疙瘩状A1脉、石英-黑云母A2脉和石英-磁铁矿A4脉)和中期B脉(矿物组合为石英-黄铁矿+黄铜矿±辉钼矿±斑铜矿)形成时,成矿热液均为岩浆流体来源,但B脉可能混入了少量大气降水;晚期低温D脉和碳酸岩脉(180～200℃)的成矿热液全部为大气降水来源.斑晶黑云母平衡水的δ 18O和δD值变化范围较大表明,黑云母形成时的热液系统主要为岩浆水,局部受区域变质水和大气降水的混染,也可能与少量黑云母斑晶受到后期绿泥石化、水云母化蚀变有关.绿泥石蚀变主要由岩浆流体作用形成,但混入了一些大气降水,导致其δ 18O值少量降低.绢云母平衡的水的δ18O值和δD值(4.6‰和-19.4‰)表明,绢云母是大气降水与千枚岩共同作用的结果.总体来说,铜厂矿床钾硅酸盐化、绿泥石化蚀变,以及钾硅酸盐化阶段形成的A脉和B脉,均由岩浆流体作用引起,大气降水在绿泥石化阶段进入蚀变-矿化系统,而绢云母化、晚期低温D脉和碳酸盐脉均是大气降水作用的产物. 相似文献
13.
The Miduk porphyry copper deposit is located in Kerman province, 85 km northwest of the Sar Cheshmeh porphyry copper deposit, Iran. The deposit is hosted by Eocene volcanic rocks of andesitic–basaltic composition. The porphyry‐type mineralization is associated with two Miocene calc‐alkaline intrusive phases (P1 and P2, respectively). Five hypogene alteration zones are distinguished at the Miduk deposit, including magnetite‐rich potassic, potassic, potassic–phyllic, phyllic and propylitic. Mineralization occurs as stockwork, dissemination and nine generations (magnetite, quartz–magnetite, barren quartz, quartz‐magnetite‐chalcopyrite‐anhydrite, chalcopyrite–anhydrite, quartz‐chalcopyrite‐anhydrite‐pyrite, quartz‐molybdenite‐anhydrite ± chalcopyrite ± magnetite, pyrite, and quartz‐pyrite‐anhydrite ± sericite) of veinlets and veins. Early stages of mineralization consist of magnetite rich veins in the deepest part of the deposit and the main stage of mineralization contains chalcopyrite, magnetite and anhydrite in the potassic zone. The high intensity of mineralization is associated with P2 porphyry (Miduk porphyry). Based on petrography, mineralogy, alteration halos and geochemistry, the Miduk porphyry copper deposit is similar to those of continental arc setting porphyry copper deposits. The Re‐Os molybdenite dates provide the timing of sulfide mineralization at 12.23 ± 0.07 Ma, coincident with U/Pb zircon ages of the P2 porphyry. This evidence indicates a direct genetic relationship between the Miduk porphyry stock and molybdenite mineralization. The Re‐Os age of the Miduk deposit marks the main stage of magmatism and porphyry copper formation in the Central Iranian volcano‐plutonic belt. 相似文献
14.
安徽沙溪斑岩型铜金矿床成岩序列及成岩成矿年代学研究 总被引：10，自引：7，他引：3
沙溪矿床是长江中下游成矿带中典型的斑岩型铜金矿床,位于庐枞盆地北外缘、郯庐断裂内,矿床成岩成矿时代确定对该矿床成因研究及区域成矿规律的认识具有重要意义。在详细野外地质工作的基础上,采集沙溪矿床与成矿有关的主要岩浆岩样品(粗斑闪长玢岩、黑云母石英闪长玢岩、中斑石英闪长玢岩、细斑石英闪长玢岩和闪长玢岩)和与黄铜矿密切共生的辉钼矿,分别利用Cameca、LA-ICP-MS U-Pb和Re-Os同位素定年方法,获得矿床内主要岩浆岩的成岩年龄(130.60±0.97Ma、129.30±1.00Ma、127.10±1.50Ma、129.46±0.97Ma和126.7±2.1Ma)以及成矿年龄(130.0±1.0Ma),并重新厘定了沙溪岩体从早到晚岩浆的侵位序列。通过区域对比,提出长江中下游存在两阶段斑岩型铜金矿化,沙溪矿床为长江中下游成矿带第二阶段形成的斑岩型矿床,沙溪矿床的成岩成矿作用既不同于庐枞盆地,也不同于断隆区第一阶段的斑岩矿床,而是受郯庐断裂和长江断裂动力学演化联合作用的产物。 相似文献
15.
16.
F. Darabi-Golestan R. Ghavami-Riabi H. Asadi-Harooni 《Arabian Journal of Geosciences》2013,6(12):4821-4831
Dalli Cu–Au porphyry deposit was occurred in the igneous diorite, quartz diorite porphyry (QDP), and volcanic rocks such as porphyritic amphibole andesite, andesite (AND), dacite, and pyroclastics during the late Miocene to Pliocene. Regolith investigations and Advanced Spaceborne Thermal Emission and Reflection Radiometer images were used to identify the anomalous areas. According to lithogeochemical survey (from boreholes and trenches) in Northern Dalli Cu–Au porphyry, the potassic, chlorite, sericite, propylitic, and argillic alterations have been found and mineralization was basically associated with potassic and quartz–sericite alterations. The alteration is dominantly moderate quartz chlorite?±?sericite magnetite with 1–10 mm wide quartz?±?magnetite veinlets. The elevated copper–gold values are correlated with density of stockworking and mineralization. The intensity of the mineralization is high in the contact of QDP and AND with increases in pyrite and chalcopyrite values. Malachite, native Cu, and bornite were used to identify supergene, transition, and hypogene zone. In addition, molybdenum increased near to the center of granodiorite intrusion. And besides, from depth to surface in DDH03 and wall rock to mineralization zones, a sequence of Mo→Cu (Au)→Au (Cu) was recorded and the mineralization temperature cooled down (from high to low). The alteration is characterized by specific pattern and structure in Dalli Cu–Au porphyry deposit. The alteration model was followed from the modified Lowell and Gilbert model. The porphyry is stockworked by quartz veins and by quartz magnetite veins. Vein distribution and ore mineralogy vary between the different alteration zones. Due to the formation of an iron cap in the supergene, especially in the southern hills, supergene grade was higher than hypogene zone. Also, hematite, as a dominant Fe oxide in DDH03 borehole with minor limonite, jarosite, and goethite created thickness about 150–270 m in supergene zone; finally, this finding show a possibility of an extensive mineralization. 相似文献
17.
V. A. Kovalenker G. D. Kiseleva T. L. Krylova O. V. Andreeva 《Geology of Ore Deposits》2011,53(2):93-125
The Bugdaya Au-bearing W-Mo porphyry deposit, Eastern Transbaikal Region, Russia, is located in the central part of volcanic
dome and hosted in the large Variscan granitic pluton. In its characteristics, this is a Climax-type deposit, or an Mo porphyry
deposit of rhyolitic subclass. The enrichment in gold is related to the relatively widespread vein and veinlet gold-base-metal
mineralization. More than 70 minerals (native metals, sulfides, sulfosalts, tellurides, oxides, molybdates, wolframates, carbonates,
and sulfates) have been identified in stockwork and vein ores, including dzhalindite, greenockite, Mo-bearing stolzite, Ag
and Au amalgams, stromeyerite, cervelleite, and berryite identified here for the first time. Four stages of mineral formation
are recognized. The earliest preore stage in form of potassic alteration and intense silicification developed after emplacement
of subvolcanic rhyolite (granite) porphyry stock. The stockwork and vein W-Mo mineralization of the quartz-molybdenite stage
was the next. Sericite alteration, pyritization, and the subsequent quartz-sulfide veins and veinlets with native gold, base-metal
sulfides, and various Ag-Cu-Pb-Bi-Sb sulfosalts of the gold-base-metal stage were formed after the rearrangement of regional
pattern of tectonic deformation. The hydrothermal process was completed by argillic (kaolinite-smectite) assemblage of the
postore stage. The fluid inclusion study (microthermometry and Raman spectroscopy) allowed us to establish that the stockwork
W-Mo mineralization was formed at 550–380°C from both the highly concentrated Mg-Na chloride solution (brine) and the low-density
gas with significant N2 and H2S contents. The Pb-Zn vein ore of the gold-base-metal stage enriched in Au, Ag, Bi, and other
rare metals was deposited at 360–140°C from a homogeneous Na-K chloride (hydrocarbonate, sulfate) hydrothermal solution of
medium salinity. 相似文献
18.
《International Geology Review》2012,54(10):1145-1160
Lanjiagou is a porphyry Mo deposit in terms of its alteration zonation and mineralization associated with granitic intrusions and predominance of quartz vein-hosted molybdenum mineralization. It is the largest Mo deposit in North China Craton (404,000 t). There is an intimate spatial/temporal association between all stages of mineralization and Early Jurassic granitic intrusions at Lanjiagou. Most of the molybdenum was emplaced during the principal hydrothermal (PH) stage (184.6 ± 1.3 – 185.6 ± 1.4 Ma), contemporaneously with intrusion of fine-grained porphyritic granite (188.9 ± 1.2 Ma) into a granite batholith (193 ± 3 Ma). The PH mineralization stage is mainly hosted by a quartz-dominated stockwork associated with phyllic alteration in the fine-grained porphyritic granite. This stage was followed by the late hydrothermal (LH) activity. Thick Mo-rich quartz veins were emplaced during the LH stage and cut the porphyry ore bodies. A ring breccia zone formed during the last hydrothermal stage and apparently cuts both the porphyry and the quartz vein ore bodies. The main hydrothermal vein stages have predominantly concentric and radial vein orientations centred on the ring breccia zone. Most of the concentric veins have shallow dips, whereas the radial veins are subvertical. The LH veins have predominantly NEE and NW orientations in the deposit and are moderately inclined. We surmise that the veining was controlled by the local stress regime generated by the intrusion of a large, deep pluton that we interpreted to be the source of the granites, the breccia zone, and the molybdenum mineralization. Resurgence within the magma chamber reactivated the steep concentric structures in a reverse sense, and accumulation of magmatic and/or fluid pressure resulted in explosive brecciation, producing the ring breccia zone. A predominantly late set of NW-trending, post-ore felsic dikes, associated with the regional structures, are a consequence of far-field stresses exceeding local stresses in the deposit. 相似文献
19.
安徽西冲钼矿床细粒花岗岩的岩石定年、岩石化学及与成矿的关系研究 总被引：1，自引：0，他引：1
西冲钼矿是大别成矿带东段近年新发现的斑岩型钼-多金属矿床,其矿床学和矿床地球化学研究少见报导。该研究成果丰富了我国斑岩-矽卡岩型钼钨-多金属矿床研究成果,同时对指导区域找矿具有一定意义。本文在详细的野外地质调研基础上,对大别成矿带西冲钼矿区出露的主要岩石单元、矿化和蚀变特征、细粒花岗岩的岩石学、岩石化学和成岩年代学进行了系统的研究。结果表明,矿区出露的主要侵入岩单元由老至新依次为:石英二长岩、细粒花岗岩(130.8±1.1Ma)及双峰式脉岩组合(131.9±1.4Ma和131.3±1.6Ma),其均为燕山期岩浆活动产物,产于华北与扬子陆块拼合后的陆内环境。矿化类型以脉状、网脉状和浸染状为主,为一斑岩型钼-多金属矿床。矿区蚀变发育,包括黑云母-磁铁矿化、钾长石化、硅化、石英-绢云母化、石英-绿帘石化、绿泥石-碳酸盐化和泥化,且空间上具有一定的分带规律。矿区已知矿化、蚀变及Cu-Mo化探异常的空间展布与细粒花岗岩关系密切,且细粒花岗岩中具有高的Mo含量,表明该矿床的形成主要与细粒花岗岩有关。岩石化学结果表明,细粒花岗岩属过铝质-准铝质、高钾钙碱性-钾玄质过渡岩石,锆石U-Pb年龄与双峰式脉岩的在误差范围内一致,表明其均形成于大别造山带大规模伸展背景。 相似文献
20.
Akira IMAI 《Resource Geology》2000,50(1):1-23
Abstract: The Mamut deposit of Sabah, East Malaysia, is a porphyry type Cu‐Au deposit genetically related to a quartz monzonite (“adamellite”) porphyry stock associated with upper Miocene Mount Kinabalu plutonism. The genesis of the Mamut deposit is discussed based on petrology of the intrusives in the Mount Kinabalu area combined with ore– and alteration–petrography, fluid inclusion and sulfur isotope studies. Groundmass of the adamellite porphyry at Mamut is rich in K which suggests vapor transport of alkaline elements during the mineralizing magmatic process, while the groundmass of the post‐ore “granodiorite” porphyry at Mamut contains small amounts of normative corundum suggesting depletion in alkaline elements at the root zone of the magma column. Sub‐dendritic tremolitic amphibole rims on hornblende phenocrysts in the Mamut adamellite porphyry suggest interaction between the mineralizing magma and the exsolved fluids. Occurrences of clinopyroxene microphenocrysts and pseudomor‐phic aggregates of shredded biotite and clinopyroxene after hornblende phenocrysts in the barren intrusives imply lower water fugacity and decreasing in water fugacity, respectively. Compositional gap between the core of hornblende phenocrysts and the tremolitic amphibole rims and those in the groundmass of the Mamut adamellite porphyry suggests a decrease in pressure. Higher XMg (=Mg/(Mg+Fe) atomic ratio) in the tremolitic amphibole rims in the Mamut adamellite porphyry compared to those of the barren intrusions suggests high oxygen fugacity. High halogen contents of igneous hydrous minerals such as amphiboles, biotite and apatite in the Mamut adamellite porphyry suggest the existence of highly saline fluids during the intrusion and solidification of the mineralizing magma. Fluid inclusions found in quartz veinlet stockworks are characterized by abundant hypersaline polyphase inclusions associated with subordinate amounts of immiscible gaseous vapor. Both Cu and Au are dispersed in disseminated and quartz stockwork ores. Chalcopyrite and pyrrhotite as well as magnetite are the principal ore minerals in the biotitized disseminated ores. Primary assemblage of intermediate solid solution (iss) and pyrrhotite converted to the present assemblage of chalcopyrite and pyrrhotite during cooling. Subsequent to biotitization, quartz veinlet stockworks formed associated with retrograde chlorite alteration. The Cu‐Fe sul–fides associated with stockwork quartz veinlet are chalcopyrite and pyrite. Overlapping Pb and Zn and subsequent Sb mineralizations were spatially controlled by NNE‐trending fractures accompanying the phyllic and advanced argillic alteration envelope. Sulfur isotopic composition of ore sulfides are homogeneous (about +2%) throughout the mineralization stages. These are identical to those of the magmatic sulfides of Mount Kinabalu adamellitic rocks. 相似文献