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滇西南澜沧江带红豆山铜矿花岗斑岩地质地球化学特征及成岩时代 总被引：2，自引：0，他引：2
南澜沧江火山弧带红豆山花岗斑岩属于过铝质钾玄岩性S型花岗岩,SiO_2含量为71.1%~74.4%,全碱含量高(K_2O+Na_2O=8.4%~9.4%),富钾(K_2O/Na_2O=3.9~5.0),铝饱和指数(A/CNK)为1.06~1.21;具轻稀土元素富集特征,负Eu异常(δ Eu=0.53~0.74);相对富集大离子亲石元素(LILE,如Rb、Ba、Th、U等),但亏损Sr、P、Ti等元素。地球化学特征表明,红豆山花岗斑岩具火山弧花岗岩与同碰撞花岗岩的特征,为活动大陆边缘弧的产物。红豆山花岗斑岩的LA-ICP-MS锆石U-Pb年龄为220.3±3.6Ma,形成于晚三叠世。红豆山花岗斑岩的地球化学特征和形成时代与小定西组基性火山岩非常相似,两者是同一期岩浆活动不同阶段的产物。 相似文献
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The Jinping terrane is situated in the southern segment of the Ailaoshan ore belt, Sanjiang Tethyan Orogen (SW China). The Paleogene intrusions in Jinping consist of syenite porphyry, fine-grained syenite and biotite granite stocks/dikes, and contain relatively low TiO2 (0.21–0.38 wt%), P2O5 (0.01–0.35 wt%), and high Na2O (2.00–4.62 wt%) and K2O (4.48–7.06 wt%), belonging to high-K alkaline series. Paleogene gold mineralization in Jinping comprises four genetic types, i.e., orogenic, alkali-rich intrusion-related, porphyry and supergene laterite. The NW–NNW-trending faults and their subsidiaries are the major ore-controlling structures. The orogenic Au mineralization, dominated by polymetallic sulfide-quartz veins, occurs in the diorite and minor in Silurian-Devonian sedimentary rocks. It contains a CO2-rich mesothermal fluid system generated from the mixing of mantle-derived fluids with crustal-derived metamorphic fluids, and the ore-forming materials were upper crustal- or orogenic-derived. The alkali-rich intrusion-related Au mineralization is hosted in the Ordovician-Silurian sedimentary rocks and minor in the Paleogene alkaline intrusions, and the Au orebodies occur predominantly in the alteration halos. It contains a CO2-bearing, largely metamorphic-sourced mesothermal fluid system, and the ore-forming materials were derived from the ore-hosting rocks and minor from the alkali-rich intrusions. The porphyry Cu-Mo-Au mineralization occurs in the granite/syenite porphyries and/or along their contact skarn, with the mineralizing fluids being magmatic-hydrothermal in origin. The former two hypogene Au mineralization types in Jinping were mainly formed in the late Eocene (ca. 34–33 Ma) and slightly after the porphyry Cu-Mo-Au mineralization (ca. 35–34 Ma), which is coeval with the regional Himalayan orogenic event. Subsequent weathering produced the laterite Au mineralization above or near the hypogene Au orebodies. 相似文献
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The large low-grade Piaotang W–Sn deposit in the southern Jiangxi tungsten district of the eastern Nanling Range, South China, is related to a hidden granite pluton of Jurassic age. The magmatic-hydrothermal system displays a zonation from an inner greisen zone to quartz veins and to peripheral veinlets/stringers (Five-floor zonation model). Most mineralization is in quartz veins with wolframite > cassiterite. The hidden granite pluton in underground exposures comprises three intrusive units, i.e. biotite granite, two-mica granite and muscovite granite. The latter unit is spatially associated with the W–Sn deposit.Combined LA-MC-ICP-MS U–Pb dating of igneous zircon and LA-ICP-MS U–Pb dating of hydrothermal cassiterite are used to constrain the timing of granitic magmatism and hydrothermal mineralization. Zircon from the three granite units has a weighted average 206Pb/238U age of 159.8 ± 0.3 Ma (2 σ, MSWD = 0.3). The cathodoluminescence (CL) textures indicate that some of the cassiterite crystals from the wolframite-cassiterite quartz vein system have growth zonations, i.e. zone I in the core and zone II in the rim. Dating on cassiterite (zone II) yields a weighted average 206Pb/238U age of 159.5 ± 1.5 Ma (2 σ, MSWD = 0.4), i.e. the magmatic and hydrothermal systems are synchronous. This confirms the classical model of granite-related tin–tungsten mineralization, and is against the view of a broader time gap of >6 Myr between granite magmatism and W–Sn mineralization which has been previously proposed for the southern Jiangxi tungsten district. The elevated trace element concentrations of Zr, U, Nb, Ta, W and Ti suggest that cassiterite (zone II) formed in a high-temperature quartz vein system related to the Piaotang granite pluton. 相似文献
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This paper discusses new structural, kinematic and geochronological data from polymetallic (Pb-Zn-Cu-Ag ± Au) vein-type deposits hosted in the metamorphic basement of the southern Sierras de Córdoba. A Carboniferous age was established for the hydrothermal event between ∼329 and 315 Ma (Late Mississippian-Early Pennsylvanian) by the K/Ar fine-fraction dating method of sericitic alteration related to metallic ore deposition in the Las Guindas and Oro districts. The obtained ages postdate the spatially associated Devonian magmatism and overlap the A-type Early Carboniferous magmatism defined for the Eastern Sierras Pampeanas. The presence of non-exhumed granitic bodies at shallow depths, possibly related to mineralization, is supported by available geophysical and field evidence.The strain fabric and 3-D kinematic analyses constitute first kinematic data for the Carboniferous basement of the Southern Sierras Pampeanas demonstrating that mineralization was controlled by NNW- and ENE-trending brittle-ductile transtensional shear zones that overprint the earlier high-strain deformation fabrics of the basement. Transtensional deformation has accommodated large amounts of strike-slip movements and subordinated extensional components. The calculated kinematic axes indicate a coherent kinematic pattern of the mineralized systems in the two studied districts, with a maximum extension direction oriented NNE- to NE and maximum shortening direction oriented WNW- to NW. This deformation regime, active during mineralization, point to a non-compressive setting at the Late Mississippian-Early Pennsylvanian boundary. In line with other regional evidence, we propose a distinctive Carboniferous deformational phase in the Eastern Sierras Pampeanas, dominated by transtension. This period would have occurred after the transition with the Devonian compressional/transpressional orogenic regime. 相似文献
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基于IKONOS数据的矿山开发占地信息提取 总被引：1，自引：0，他引：1
以IKONOS数据为信息源,对甘肃省白银铜矿区进行矿山开发占地信息提取实验研究.在经过预处理的图像上对研究区内的地物进行光谱采样,分析地物的光谱特征;并进一步建立合适的波段计算经验公式,用密度分割函数将矿山背景与占地信息区分开,消除了背景干扰;再根据光谱特征建立新的波段处理模型,对只有矿山占地的图像进行第二次密度分割,将矿山占地信息细分,通过目视解译为占地信息赋予属性.实地查证结果表明,利用计算机提取矿山占地信息能弥补目视解译的不足,不仅节省人力、物力、财力和时间,而且信息提取结果准确,具有实际应用的意义,对同类地区的矿山占地信息提取具有一定的参考价值. 相似文献
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湖南桃源县西安钨金矿床位于湘西矿化集中区西安金锑钨成矿带的中部,距沃溪钨锑金大型矿床约15km,是湖南重要的钨金矿床。前人研究注意到该矿区内含矿地层及断裂构造叠加对矿床形成的控制作用。文章通过矿区地质研究和地球物理测量,结合区域地质演化和对前人资料的分析,发现该矿区还存在重要的褶皱构造。对该矿床的形成和分布提出了新的认识,该矿床的形成除受地层和断裂构造控制之外,还受到褶皱构造的明显控制,提出了:有利地层和缓倾斜EW向层间滑动断裂带叠加控制了矿化带的形成和分布,高角度NE向断裂是重要的导矿构造,褶皱构造的叠加控制了矿床的形成和分布,次级褶皱尤其是背斜构造的叠加则控制了矿体的形成和分布,该矿床的成矿有利地段是地层和层间滑动断裂带之上叠加了褶皱构造的地段。 相似文献
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沟系土壤地球化学测量在贵州普晴锑金矿勘查区应用与找矿效果 总被引：2，自引：0，他引：2
通过沟系土壤地球化学测量方法在普晴锑金矿勘查区中的实施,确定各元素异常下限值为Au7×10-9、Sb10×10-6、Cu200×10-6、As30×10-6,发现了一批有价值的地球化学异常,对各元素地球化学异常区的找矿潜力进行分析,结合地层、岩性等有利控矿因素综合评判主成矿元素异常、元素组合异常圈定4个找矿靶区,确定了各靶区的主要找矿矿种,对各靶区进行了必要的山地工程查证,取得了较好的找矿效果。实践证明沟系土壤地球化学测量找矿方法在本区是有效的,认识到在当前老矿区外围找矿中成矿元素弱异常、多元素组合弱异常区具有重要找矿意义。在此基础上较系统的总结了沟系土壤地球化学找矿方法步骤。 相似文献
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HUANG Yonggao LI Yingxu HAN Fei JIA Xiaochuan YANG Xuejun LI Guangming KANG Zhiqiang WANG Chunzeng 《《地质学报》英文版》2020,94(4):1314-1316
正Objective The giant Nyainqentanglha granitic batholith, located in the Lhasa Terrane, is the youngest granite pluton emplaced at 18.3–11.0 Ma during the Miocene epoch. A series of NE-striking sinistral normal ductile shear zones developed on its north and south sides. The ductile shear zones are considered to be the western boundary faults of the Yadong-Gulu rift system and have the potential to provide critical temporal constraints for the large-scale East–West extension event in the Tibetan Plateau. Based on 相似文献