东天山小尖山金矿床成矿流体特征及成矿模式探讨     

蒋东祥  毛启贵  刘家军  于明杰  卫晓峰 《地质学报》2021,95(2):449-462

小尖山金矿床产于东天山康古尔韧性剪切带南缘,对该矿床流体特征和矿床成因类型了解较少。矿区普遍发育低绿片岩相变质,矿床由多条走向为100°~120°的陡倾斜蚀变岩型矿体组成,金平均品位3.11×10^-6~24.99×10^-6;成矿过程可划分为3个阶段:(1)黄铁矿-磁铁矿-绿泥石-绢云母-石英阶段;(2)黄铁矿-黄铜矿-自然金-石英-绿泥石阶段;(3)石英-方解石-贫硫化物阶段。本文通过对矿床不同成矿阶段石英脉内发育的流体包裹体进行了岩相学、显微测温与氢氧同位素研究分析,发现矿床主要发育H₂O-CO₂及气液两相流体包裹体,从早至晚成矿过程中流体内CO₂包裹体逐渐减少,气液两相包裹体内气液比逐渐减小。各成矿阶段包裹体显微测温结果表明,从早至晚成矿流体均一温度分别为216.9~396.4℃、183.1~319.2℃与145.1~220.8℃;成矿流体盐度分别为1.40%~10.11%NaCleq、1.91%~11.22%NaCleq与1.63%~6.74%NaCleq,成矿流体属于中低温、中低盐度的NaCl-H₂O-CO₂体系,并经历了从中温、中盐度流体向低温、低盐度流体的演化过程;成矿早阶段流体的δD_V-SMOW值为-22.550‰,δ¹⁸O_水值为9.44‰,指示变质水成因;成矿晚阶段δD_V-SMOW值介于-41.913‰~-34.796‰之间,平均值为-37.413‰,δ¹⁸O_水值介于1.99‰~3.98‰之间,平均值为2.99‰,指示混合水成因,但接近变质水;成矿流体主要为变质水,成矿早阶段至晚阶段具有从变质水向混合水演化的特征。综合分析,小尖山金矿床成因类型为造山型金矿,其成矿模式为早期韧性剪切变形过程中产生的变质流体在运移过程中萃取岩石中成矿物质,形成含金成矿流体,并在糜棱岩面理等裂隙处发生结晶作用,导致金的初步富集;晚期地壳快速抬升,地质体由韧性变形向脆-韧性、脆性变形转变,伴随有花岗岩脉的侵入,变质流体在运移过程中从流经岩石中淋滤萃取金等成矿物质,形成含矿流体,岩浆水、大气降水的混入以及深度、压力的降低使得流体内的成矿物质在裂隙或断层发育的有利地段卸载沉淀,形成金矿体。  相似文献   

东昆仑大干沟一带铜金锑矿特征及找矿意义   总被引：1，自引：1，他引：0  

张凯  苟荣涛  刘树林  郭刚  徐俊杰  王博闻  李华南  苑静 《地质力学学报》2012,18(4):401-409

东昆仑地区处于中朝、塔里木-柴达木、扬子和印度板块的拼合部位,元古宙以来经历了多期次的裂解和拼合。该区以Au、Co、Cu、Pb、Zn、Hg、Sb、As元素组合为特征,其中多处已证实为矿致异常,共发现矿床、矿点等198处,初步显示了良好的找矿前景。目前在大干沟一带已发现铜多金属矿化带一条、金锑含矿构造蚀变带一条。矿化特征基本一致,均赋存于中三叠统闹仓坚沟组北西西向脆韧性剪切带内及两侧的灰白-烟灰色方解石石英脉内,且具有南侧金锑矿化、北侧铜多金属矿化的分带特征。   相似文献   

秦昆结合部塔秀地区隆务河组碎屑锆石LA-ICP-MSU-Pb年代学及其地质意义     

路宗悦  余心起  刘满年  张振  魏立勇  赵常存  郑鑫  寇少磊  许安民  王照翻 《现代地质》2019,33(4):691-702

秦昆结合部独特的地质组成与复杂的造山带结构受到广泛关注。前人对该地区沉积物质来源进行了初步分析,但存在较大争议。选取隆务河组碎屑岩为研究对象,运用碎屑锆石LA-ICP-MS U-Pb同位素年代学方法,探讨隆务河组物源特征。U-Pb测年结果表明,隆务河组碎屑锆石年龄谱明显分为4组:2 746~2 084 Ma,1 094~775 Ma,492~411 Ma,372~237 Ma。其中,372~237 Ma年龄组约占总体的56.79%,所占比例最大,年龄相对集中,且呈现出强烈的峰值,代表了阿尼玛卿洋向北俯冲碰撞产生的一系列构造岩浆事件,其余年龄段所占比例则较少。综合分析显示,隆务河组碎屑沉积物质来源较为复杂,具有明显的多元性,存在祁连造山带、柴北缘构造带和东昆仑造山带3个物源区,其中东昆仑造山带提供了大部分物源,为隆务河组贡献最大的物源区。  相似文献   

西昆仑大红柳滩地区原划上三叠统克勒青河群中发现二叠纪化石     

崔海涛  崔建堂  殷永魁 《陕西地质》2019,(1):36-41

通过西昆仑大红柳滩一带地质填图和实测地层剖面,从原划上三叠统克勒青河群中采到了大量孢粉和珊蝴、菊石类等化石,经鉴定其形成时代主体为二叠纪,经区域地层对比,重新厘定为二叠纪黄羊岭群。该生物化石的取得,为分析研究西昆仑微陆块及巴颜喀拉晚古生代—中生代边缘裂陷盆地的地质构造演化,提供了新资料。  相似文献   

单级弹簧主动隔振系统建模与分析     

刘川  刘胜芬  周云耀  吕永清 《内陆地震》2014,28(3):234-239

主动隔振系统具有隔振频带宽,能够在低频处取得较好隔振效果的优点,因而成为研究的热点。基于单级弹簧主动隔振系统建立数学模型,着重分析了系统位移反馈、速度反馈和加速度反馈3种反馈量对系统隔振性能的影响。结果表明:位移反馈使系统固有角频率提高,低频处隔振效果增强,而高频处隔振效果略有降低;速度反馈使系统在固有角频率附近的隔振效果有很好的改善,但是在其他频段的隔振效果基本没有变化;加速度反馈使得系统固有角频率减小,并且在高频段的隔振效果增加。这对主动隔振系统控制器的设计具有实际指导意义。  相似文献   

Contribution of surface roughness to simulations of historical deforestation     

《Physics and Chemistry of the Earth》2015

Surface roughness which partitions surface net radiation into energy fluxes is a key parameter for estimation of biosphere–atmosphere interactions and climate variability. An earth system model of intermediate complexity (EMIC), MPM-2, is used to derive the impact of surface roughness on climate from simulations of historical land cover change effects. The direct change in surface roughness leads to a global surface warming of 0.08 °C through altering the turbulence in the boundary layer. The regional temperature response to surface roughness associated deforestation is very strong at northern mid-latitudes with a most prominent warming of 0.72 °C around 50°N in the Eurasia continent during summer. They can be explained mainly as direct and indirect consequences of decreases in surface albedo and increases in precipitation in response to deforestation, although there are a few significant changes in precipitation. There is also a prominent warming of 0.25 °C around 40°N in the North American continent. This study indicates that land surface roughness plays a significant role which is comparable with the whole land conversion effect in climate change. Therefore, further investigation of roughness–climate relationship is needed to incorporate these aspects.  相似文献   

Hydrothermal alteration and ore-forming fluids associated with gold-tellurium mineralization in the Dongping gold deposit,China     

《Ore Geology Reviews》2017

The Dongping gold deposit hosted in syenites is one of the largest hydrothermal gold deposits in China and composed of ore veins in the upper parts and altered zones in the lower parts of the ore bodies. Pervasive potassic alteration and silicification overprint the wall rocks of the ore deposit. The alteration minerals include orthoclase, microcline, perthite, quartz, sericite, epidote, calcite, hematite and pyrite, with the quartz, pyrite and hematite assemblages closely associated with gold mineralization. The phases of hydrothermal alteration include: (i) potassic alteration, (ii) potassic alteration - silicification, (iii) silicification - epidotization - hematitization, (iv) silicification - sericitization - pyritization and (v) carbonation. Mass-balance calculations in potassic altered and silicified rocks reveal the gain of K₂O, Na₂O, SiO₂, HFSEs and transition elements (TEs) and the loss of REEs. Most major elements were affected by intense mineral reactions, and the REE patterns of the ore are consistent with those of the syenites. Gold, silver and tellurium show positive correlation and close association with silicification. Fluid inclusion homogenization temperatures in quartz veins range from 154 °C to 382 °C (peak at 275 °C–325 °C), with salinities of 4–9 wt.% NaCl equiv. At temperatures of 325 °C the fluid is estimated to have pH = 3.70–5.86, log fO₂ = − 32.4 to − 28.1, with Au and Te transported as Au (HS)₂⁻ and Te₂^2 − complexes. The ore forming fluids evolved from high pH and fO₂ at moderate temperatures into moderate-low pH, low fO₂ and low temperature conditions. The fineness of the precipitated native gold and the contents of the oxide minerals (e.g., magnetite and hematite) decreased, followed by precipitation of Au- and Ag-bearing tellurides. The hydrothermal system was derived from an alkaline magma and the deposit is defined as an alkaline rock-hosted hydrothermal gold deposit.  相似文献   

The Status of Lightning Thermal Effect Observation by Remote Sensing     

Li Qing  Lei Lianfa  Wang Zhenhui  Wei Ming  Li Dongshuai 《地球科学进展》2017,32(5):481-487

  相似文献   

陕南镇巴地区中-晚三叠世界线富锂黏土岩的发现及找矿意义     

周伟  祁晓鹏  张嘉升  徐磊  杨杰  高景民 《岩石矿物学杂志》2024,43(1):47-62

首次报道了扬子板块北缘镇巴地区中-晚三叠世界线黏土岩锂的超常富集,黏土岩产于关岭组(T₂g)/须家河组(T₃x)平行不整合界面,为古风化壳沉积物,Li₂O品位0.08%～0.11%,最高达0.22%,超过了该类型矿产的边界品位(0.06%),界线黏土岩的岩石学特征、矿物组成及岩石成因亟待查明。本文通过XRD分析、TIMA分析以及详细的地球化学研究,查明了界线黏土岩的矿物组成,探讨了黏土岩形成的沉积环境及物质来源,提出了不整合面黏土岩类关键金属矿产的综合找矿方向。研究表明,镇巴地区T₂/T₃界线黏土岩主要由石英、伊利石、高岭石组成,并含有极少量绿泥石、蒙脱石和铝绿泥石。主量元素(SiO₂、Al₂O₃、^TFe₂O₃、TiO₂)特征表明界线黏土岩属于铝土质泥岩,黏土岩CIA值(化学蚀变指数)为85～93,ICV值(成分变异指数)为0...  相似文献   

秦岭造山带结构与演化若干问题的再认识   总被引：15，自引：0，他引：15  

杨志华  邓亚婷 《高校地质学报》1999,5(2):121-136

本文详细论述了北秦岭与商丹带、南秦岭、勉略带和太白－佛坪－汉南带的组成、结构特征;重新划分和阐述了秦岭造山带的构造单位及其发展演化。提出秦岭是由五类岩石地层地质体按非线性、混沌动力学的关系组合在一起并拼贴、镶嵌、叠置、堆垛而成的综合构造体,是南北与东西共存的构造格局。其经历了太古宙－古元古代陆核或古陆块增生或拼贴的发展阶段,中－新元古代板块构造体制发展阶段,震旦纪－三叠纪板内海相沉积盆地与造山带转换的发展阶段．印支期以来陆相沉积盆地和造山带转换的抽拉－逆冲岩片构造(或抽拉构造)体制的发展阶段。  相似文献