鄂尔多斯盆地纳岭沟铀矿床绿泥石特征及地质意义   总被引：3，自引：0，他引：3  

夏菲  孟华  聂逢君  严兆彬  张成勇  李满根 《地质学报》2016,90(12):3473-3482

纳岭沟铀矿床位于鄂尔多斯盆地北部,具有明显的后期热液作用的特征,矿体空间展布主要受控于绿色-灰色砂岩的过渡界面,与绿泥石化的蚀变砂岩关系密切。通过对纳岭沟铀矿床不同颜色砂岩中的绿泥石进行详细的岩相学研究和电子探针化学成分分析,依据绿泥石的成因与共生矿物的关系,识别出绿泥石主要的3种类型:填隙物型绿泥石,片状与黄铁矿共生型绿泥石以及黑云母蚀变型绿泥石;同时通过绿泥石的Fe-Si图解确定了纳岭沟铀矿床不同颜色砂岩中的绿泥石主要为铁镁绿泥石和密绿泥石。根据Al/(Fe+Mg+Al)-Mg/(Fe+Mg)的关系图解确定出不同颜色砂岩中的绿泥石具有铁镁质流体和泥质两种来源,通过绿泥石中主要阳离子与镁的关系图解和计算得出的绿泥石形成温度共同确定出绿泥石是多期次的中低温热液流体作用的产物。综合研究表明,纳岭沟铀矿床的绿泥石形成至少经历了温度稍高的还原性流体和温度稍低的氧化性流体等两个期次的流体作用,稍高温的还原性流体与成矿关系更为重要。与绿泥石形成有关的热液流体作用不仅带入了部分铀,还促进了铀的活化和运移。  相似文献   

南京周家山下蜀黄土石英颗粒特征及其物源意义   总被引：1，自引：1，他引：0  

徐洪阳  郑祥民  周立旻  任少芳  王小玉  玄晓娜 《沉积学报》2016,34(6):1176-1186

下蜀黄土的成因和物源一直是学术界研究的热点。对南京周家山下蜀黄土的石英粒度和石英表面微结构进行分析,结果显示:粉砂粒级石英颗粒（5~50 μm）占绝对优势;<20 μm组分平均含量为42.76%,<30 μm组分平均含量为62.98%;粒度分布曲线和累积曲线总体具有颗粒偏细,呈正偏态,分选较差,峰形尖锐,双峰曲线不对称的特征;粒级-标准偏差曲线呈“双峰”分布,两个明显的标准偏差峰值分别出现在7.962 1 μm和39.905 2 μm。石英颗粒表面形态主要以次棱角状为主;表面机械结构具有丰富的蝶形坑、曲脊、贝壳状断口,部分表面出现平行节理面、V形坑;不同粒级组分表面形态和机械结构特征存在差异。分析表明,南京周家山下蜀黄土属典型风成成因堆积物,是多源区物质高度混合搬运堆积的结果。  相似文献   

赣北大湖塘地区昆山W-Mo-Cu矿床侵入岩锆石U-Pb、辉钼矿Re-Os年代学及地质意义   总被引：2，自引：0，他引：2  

张明玉  丰成友  李大新  王辉  周建厚  叶少贞  汪国华 《大地构造与成矿学》2016,(3):503-516

昆山W-Mo-Cu矿床地处赣北九岭矿集区南部,距大湖塘超大型钨矿床狮尾洞矿区仅3 km。矿床目前处于详查阶段,已探明钨达中型规模,同时伴生中型钼矿及小型铜矿,具有良好的找矿潜力。昆山矿床矿化样式较为单一,W-Mo-Cu矿体以石英脉形式产出,主要赋存在燕山期侵入岩顶部与新元古界双桥山群浅变质岩的外接触带,具有"上钨中钼下铜"的特点,明显区别于大湖塘矿床矿体主要产在燕山期侵入岩与晋宁期黑云母花岗闪长岩的内外接触带,具细脉浸染型白钨矿、热液爆破角砾岩型钨铜矿及石英脉型黑钨矿"三位一体"的矿化特征。本文在详细的野外地质调查基础上,对昆山W-Mo-Cu矿床的成岩成矿时代进行了详细研究,并探讨了其地质意义。利用LA-ICP-MS锆石U-Pb法获得矿区内呈岩株状产出的似斑状花岗岩的年龄为151.7±1.3 Ma,晚期花岗斑岩脉的年龄为136.6±2.5 Ma;利用辉钼矿Re-Os法,获得辉钼矿Re-Os等时线年龄和加权平均年龄分别为151.0±1.3 Ma和150.0±1.0 Ma,厘定矿床成矿时代为晚侏罗世,且与似斑状花岗岩有关。结合前人所得高精度成岩成矿年龄数据,认为赣北地区燕山期成岩成矿具多期性,可分为160~150 Ma(塔前、朱溪钨多金属矿床)、140 Ma(大湖塘钨多金属矿床)和125 Ma(香炉山钨矿),主要集中于150~140 Ma。晚侏罗世,华南地区全面进入岩石圈"伸展-减薄"的地球动力学背景,赣北地区燕山期成岩成矿可能与这一构造背景有关。昆山矿床具"上钨中钼下铜"的分带模式,其成因值得进一步研究。  相似文献   

广西珊瑚钨锡矿床成矿年代学研究及其地质意义   总被引：2，自引：0，他引：2  

卢友月  付建明  程顺波  马丽艳  黄振标  闭义钦 《大地构造与成矿学》2016,(5):939-948

珊瑚钨锡矿床位于富贺钟钨锡多金属成矿集中区的中部,是南岭钨锡多金属成矿带内典型的热液石英脉型矿床之一。本文采用白云母~(40)Ar-~(39)Ar法和石英流体包裹体Rb-Sr法,对矿床V32号含矿石英脉进行精细年代学研究,获得石英脉中白云母~(40)Ar-~(39)Ar坪年龄为101.7±0.7 Ma(MSWD=0.34),正等时线年龄为102.0±1.0 Ma(MSWD=1.17);石英流体包裹体Rb-Sr等时线年龄为106.4±3.5 Ma(MSWD=0.83)。它们在误差范围内一致,是华南地区燕山晚期成岩成矿高峰期的产物。同时通过石英包裹体H-O同位素组成的初步分析,认为成矿流体属于"再平衡岩浆水",主要来自岩浆,在矿床深部可能存在隐伏花岗岩体。该成果对研究区域成矿规律,指导类似地区的找矿勘查工作具有重要意义。  相似文献   

坦桑尼亚西北部苏库马绿岩带含金石英脉成矿特征     

王建光  彭俊  袁杨森  司建涛  梁永安 《世界地质》2016,35(4):982-992

坦桑尼亚克拉通西北部的苏库马绿岩带是坦桑尼亚环维多利亚湖绿岩带重要的金矿聚集区。区内金矿化类型以含金石英脉为主,矿体的产出主要受剪切构造带控制。通过研究区域构造特征和岩石地球化学特征,认为苏库马绿岩带中玄武岩为弧后环境形成,流纹岩和花岗岩形成于陆弧环境,N--S向挤压作用和E--W向伸展作用是区域内主要的构造展布特征。建立了含金石英脉的成矿模式,表明具有金矿化作用的石英脉集中分布在EW、SEE、NE向剪切构造破碎带中,含金石英脉富矿体的形成经历了多期构造变形和成矿流体的叠加、富集作用。  相似文献   

胶东金翅岭金矿构造控矿规律及找矿预测          下载免费PDF全文

万方  赵国春  张竞嘉  盛肖宁  高建伟 《山东国土资源》2016,32(5)

金翅岭金矿是胶东招远北部的一个典型石英脉型金矿,构造是金矿最为重要的控矿因素。在前人资料的基础上,综合分析了矿区构造控矿特征,总结了构造控矿规律:矿脉分支复合,表现为NE向矿脉产生SN,NNE向次级矿脉,NNE向矿脉产生NE向次级矿脉;矿体厚度与金品位呈负相关,深部次级矿脉群在P4脉下盘出现;矿脉侧伏角和倾伏向变化处矿体富集,表现为SW向侧伏的P4矿脉,矿体富集于-240 m,侧伏角变大,同时倾伏向由SW向转变为NW向的部位。最后建立了平面和剖面P4矿脉的波形函数,并对深部进行了预测。  相似文献   

柴达木盆地西北缘石英闪长岩的形成时代、岩石成因及地质意义     

辜平阳  陈锐明  查显锋  董增产  庄玉军  查方勇  李培庆 《岩石矿物学杂志》2018,37(1):19-33

柴达木盆地西北缘石英闪长岩Al2O3含量较高,全碱(Alk)含量较低,Na2OK2O,铝饱和指数A/CNK为0.87~0.91,属钙碱性准铝质岩石系列。球粒陨石标准化的稀土元素配分曲线表现为轻稀土元素富集型,轻、重稀土元素分馏明显,Eu弱负异常;微量元素地球化学特征显示,岩石富集Rb、Th、U等大离子亲石元素,亏损Nb、Ta、P、Ti等高场强元素,Nb/La和Rb/Nb比值较低,具有I型花岗岩的特征。石英闪长岩Ca O/Na2O比值较高(2.32~2.64),结合源岩判别图解综合推断其源于变玄武岩的部分熔融。全岩Zr饱和温度计算结果显示初始岩浆温度768℃;岩石地球化学特征表明岩浆源区压力1.5 Ga,源岩部分熔融的残留相可能为石榴子石+角闪石+金红石。经过锆石阴极发光分析和MC-LA-ICP-MS锆石U-Pb测年,获得206Pb/238Pb加权平均年龄为252±1 Ma,代表了柴达木盆地西北缘石英闪长岩的成岩年龄。结合区域地质演化特征,认为该岩体形成于与板块俯冲有关的火山弧构造环境,是晚二叠世末期宗务隆洋壳向柴北缘欧龙布鲁克地块俯冲,变玄武岩在相对较高的温压条件下发生部分熔融形成的。  相似文献   

大兴安岭扎兰屯地区晚奥陶世石英闪长岩体岩石地球化学特征及其地质意义   总被引：2，自引：0，他引：2  

马庆  刘建峰  迟效国 《地质通报》2018,37(5):853-862

扎兰屯音河岩体被音河水系分为南、北两部分,研究发现南、北岩体形成年代不同,选取南部岩体(称为二村岩体)进行研究。二村岩体主要由石英闪长岩-英云闪长岩组成,石英闪长岩的LA-ICP-MS锆石U-Pb年龄为444.0±4.6Ma,时代为晚奥陶世。岩石化学组成相对富钠、贫钾,Na2O/K2O值大于1(1.73~3.17),属中钾钙碱性系列。岩石富含轻稀土元素、亏损重稀土元素,富集大离子亲石元素Rb、Ba、K,显著亏损Nb、Ta、P、Ti等高场强元素。矿物组成及岩石地球化学特征指示其为I型花岗岩。岩体的形成时代、构造背景与多宝山岛弧火成岩相似,为区域多宝山岛弧西南向延伸提供了新的制约。  相似文献   

Fluid Inclusion Studies of Comb Quartz and Stibnite at the Hishikari Au–Ag Epithermal Deposit,Japan     

《Resource Geology》2018,68(3):326-335

Fluid inclusion microthermometry was conducted on late‐stage barren comb quartz and the latest stibnite at the Hishikari deposit to characterize the hydrothermal activity responsible for vein formation. Eight fluid inclusion assemblages (i.e. fluid inclusions trapped at the same time, ‘FIAs’) were studied to determine the formation fluid temperatures and salinities for the comb quartz in the Shosen No. 2 vein, Sanjin ore zone, and the stibnite in the Seisen No. 1–1 vein, Yamada ore zone. The average homogenization temperatures (the formation temperatures) of the seven FIAs from the comb quartz were between 207 and 230°C, while the average homogenization temperature (the formation temperature) of an FIA from the stibnite was 113°C. The measured fluid salinities of the seven FIAs from the comb quartz were low, ranging between 0.0 and 1.1 wt% NaCl equiv., indicating that dilute fluids were responsible for the comb quartz formation. By comparison with previous microthermometric data, the formation temperatures of the studied comb quartz were higher than those of columnar adularia and comb quartz at most other veins (generally around 200°C) but were similar to those of columnar adularia at Keisen veins (230°C) in the same ore zone. The higher formation temperatures both in the Shosen and the Keisen veins in the Sanjin ore zone indicate that the fractures corresponding to the vein system at the Sanjin ore zone were main conduits for hot ascending fluids. The low formation temperature of stibnite in the latest stage (113°C) indicates that stibnite precipitation occurred during a waning stage of hydrothermal activity. Combined with previous thermodynamic data on antimony solubilities, the large discrepancy between the formation temperature of the comb quartz (200–230°C) and that of the stibnite suggests that the stibnite may have precipitated as a result of a drastic cooling of the hydrothermal system.  相似文献   

Ore-bearing fluids of the Eldorado gold deposit (Yenisei Ridge,Russia)     

N.A. Gibsher  A.A. Tomilenko  A.M. Sazonov  T.A. Bul’bak  M.O. Khomenko  M.A. Ryabukha  E.O. Shaparenko  S.A. Sil’yanov  N.A. Nekrasova 《Russian Geology and Geophysics》2018,59(8):983-996

The Eldorado low-sulfide gold-quartz deposit, with gold reserves of more than 60 tons, is located in the damage zone of the Ishimba Fault in the Yenisei Ridge and is hosted by Riphean epidote-amphibolite metamorphic rocks (Sukhoi Pit Group). Orebodies occur in four roughly parallel heavily fractured zones where rocks were subject to metamorphism under stress and heat impacts. They consist of sulfide-bearing schists with veins of gray or milky-white quartz varieties. Gray quartz predominating in gold-bearing orebodies contains graphite and amorphous carbon identified by Raman spectroscopy; the contents of gold and amorphous carbon are in positive correlation. As inferred from thermobarometry, gas chromatography, gas chromatography-mass spectrometry, and Raman spectroscopy of fluid inclusions in sulfides, carbonates, and gray and white quartz, gold mineralization formed under the effect of reduced H₂O-CO₂-HC fluids with temperatures of 180 to 490 °C, salinity of 9 to 22 wt.% NaCl equiv, and pressures of 0.1 to 2.3 kbar. Judging by the presence of 11% mantle helium (³He) in fluid inclusions from quartz and the sulfur isotope composition (7.1-17.4‰ δ³⁴S) of sulfides, ore-bearing fluids ascended from a mantle source along shear zones, where they “boiled”. While the fluids were ascending, the metalliferous S- and N-bearing hydrocarbon (HC) compounds they carried broke down to produce crystalline sulfides, gold, and disseminated graphite and amorphous carbon (the latter imparts the gray color to quartz). Barren veins of milky-white quartz formed from oxidized mainly aqueous fluids with a salinity of < 15 wt.% NaCl equiv at 150-350 °C. Chloride brines (> 30 wt.% NaCl equiv) at 150-260 °C impregnated the gold-bearing quartz veins and produced the lower strata of the hydrothermal-granitoid section. The gold mineralization (795-710 Ma) was roughly coeval to local high-temperature stress metamorphism (836-745 Ma) and intrusion of the Kalama multiphase complex (880-752 Ma).  相似文献