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新疆齐求Ⅰ金矿床毒砂找矿矿物学研究 总被引：2，自引：0，他引：2
所研究的毒砂有两个成矿阶段。早期成矿阶段结晶的毒砂不含金，晶体形态为菱形短柱状以及由此组成的双晶；晚期成矿 毒砂富含, 长柱状，毒砂成分中Fe/(S As)>0.5,As/Sb>1000，显微硬度值低于1000kg/mm^2是其含金的标型特征之一。毒砂皆属电子心型半导体，其热电系数与金矿化之间的关系目前尚不十分清楚，但是在同一粒级中，存在着热电系数愈大，含矿性愈好的趋势。 相似文献
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湘西南是湖南重要的产金区，该区金矿以脉型金矿为主。按其成矿元素组合，该区脉型金矿可划分为单金石英脉型和金-锑石英脉型；按其矿体产出形态特征，可划分为顺层式和切层式脉型金矿两种。该区脉型金矿受地层、岩性和构造控制明显，矿物组合简单，金主要以自然金形式产出。该区脉型金矿形成主要与脆、韧性剪切作用有关，雪峰山一带加里东期的剪切作用，使该区的浅变质岩发生变形，并促使地层中的成矿物质发生活化、迁移，最终富集形成金矿床，因此，该区金矿的成因类型为与剪切带有关的中低温热液金矿床。 相似文献
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本文以２８００粒自然金的研究为基础，系统讨论了自然金的标型特征。研究指出：本矿床应具较大规模，矿区内除Ｊ＿２、Ｊ＿４角砾岩体外，其余几个角砾岩体也应有一定远景，｛１１１｝、｛１１１｝＋｛１００｝、｛１１０｝的出现可指示富矿地段，自然金晶体形态的空间分带规律可确定（岩）矿体的剥蚀深度及评价外围角砾岩体的含矿性及远景；自然金中Ｂｉ可做为找矿评价的指示元素。 相似文献
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甘肃全鑫金矿矿石难浸原因初探 总被引：1，自引：0，他引：1
全鑫金矿为变质碎屑岩型金矿床,矿化类型可分为含金石英脉和破碎蚀变岩型。通过对矿石的工艺矿物学性质的研究,矿石的Au含量一般在1×10-6～4×10-6之间,并含有C有机,As,属C As型金矿石。矿石中金属矿物主要为褐铁矿、赤铁矿及黄钾铁钒,金矿物以含银自然金为主,自然金与褐铁矿关系十分密切,常以包裹体形式嵌布于其中,粒度一般为0 002mm左右。筛分后,不同粒级矿样的Au含量不同,在小于0 037mm粒级中,Au含量达4 72×10-6,分布率高达93 42%。经过小型工业堆浸试验,呈现出周期较长、浸出率较低的特征。其原因是金的单体解离和暴露不充分,浸矿液中的氰化物难以与所有的金粒发生作用。同时,矿石中石墨、C有机及其他一些粘土矿物也促使含Au溶液中的Au发生沉淀,造成浸出率降低。 相似文献
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《矿物学报》2017,(Z1)
利用光薄片鉴定、X射线衍射、主要化学成分分析、物相分析、扫描电镜背散射和载金矿物能谱分析等方法,对滇西北衙金多金属矿床万硐山矿段原生矿石中金等主要元素的赋存状态进行研究。研究表明,金的赋存形式主要有裂隙金、粒间金、包裹金,少量连生金。载金矿物以磁铁矿、菱铁矿为主,所占比例达到84.23%,其次是黄铁矿、黄铜矿、方铅矿、辉银矿、斑铜矿、磁黄铁矿、闪锌矿、斜方辉铅铋矿、石英和黑云母等。自然金的粒度按金矿物面积统计主要以显微极微粒金(0.2~5μm)、显微微粒金(5~10μm)、显微细粒金(10~20μm)及显微中粒金(20~50μm)为主,分别占17.87%、28.16%、28.19%和25.78%。按颗粒数量统计,以显微极微粒金(0.2~5μm)为主,占89.94%,其他3个粒级分别占6.51%、2.31%和1.18%,显微极微粒金粒数量多但极细,质量占比非常小,而显微微粒金—显微中粒金数量少颗粒相对大,质量占比大。电子探针和物相分析显示,矿石中金主要以独立矿物存在,包括大量的自然金和少量的银金矿,金的平均成色为890,金矿物的成色和特征反映金矿形成条件为高—中温和中等形成深度以及成矿流体主要属岩浆热液。 相似文献
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通过化学分析、扫描电镜以及工艺矿物学自动定量分析系统(MLA)等测试方法对河南嵩县下蒿坪金矿进行了系统的工艺矿物学研究,包括原矿化学组成、矿物组成、金的赋存状态、主要载金矿物嵌布特征以及矿物解离特性等。结果表明,该金矿中主要可回收的有价金属为金,其品位为3.75×10-6。该金矿的原矿矿物主要由石英、钾长石、钠长石、黄铁矿和铁白云石组成,此外还有少量的赤铁矿、萤石、白云石以及方解石。原矿中的金主要赋存在黄铁矿中,而黄铁矿大部分以细粒、微细粒形式嵌布在石英和长石颗粒中。原矿中自然金的含量非常少,多以单独的自然金颗粒形式存在。原矿磨至P80=0.074 mm(-0.074 mm粒级含量占80%)时载金矿物黄铁矿、方铅矿、闪锌矿的单体解离度相对较高,有利于通过浮选回收。 相似文献
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Large symmetric and asymmetric dunes occur in the Fraser River, Canada. Symmetric dunes have stoss and lee sides of similar length, stoss and lee slope angles <8°, and rounded crests. Asymmetric dunes have superimposed small dunes on stoss sides, sharp crests, stoss sides longer than lee sides, stoss side slopes <3° and straight lee side slopes up to 19°. There is no evidence for lee side flow separation, although intermittent separated flow is possible, especially over asymmetric dunes. Dune symmetry and crest rounding of symmetric dunes are associated with high sediment transport rates. High near-bed velocity and bed load transport near dune crests result in crest rounding. Long, low-angle lee sides are produced by deposition of suspended sediment in dune troughs. Asymmetric dunes appear to be transitional features between large symmetric dunes and smaller dunes adjusted to lower flow velocity and sediment transport conditions. Small dunes on stoss sides reduce near-bed flow velocity and bed load transport, causing a sharper dune crest. Reduced deposition of suspended sediment in troughs results in a short, steep lee slope. Dunes in the Fraser River fall into upper plane bed or antidune stability fields on flume-based bedform phase diagrams. These diagrams are probably not applicable to large dunes in deep natural flows and care must be taken in modelling procedures that use phase diagram relations to predict bed configuration in such flows. 相似文献
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Gold Grade and Tonnage Models of the Gold Deposits, China 总被引：4，自引：0，他引：4
Abstract: The gold grade and tonnage modelling is applied to some types of the gold deposits in China, including placer, Archaean lode, slate belt, Carlin, volcanogenic, skarn and Shandong Peninsula, among others. The Shandong Peninsula type denotes the gold deposit, which was formed in an intensely reshaped Archaean greenstone belt. The modelling results show: (1) the Archaean lode gold deposits of China are similar to the Homestake type in gold grades. (2) The Chinese slate belt type gold deposits are marked by moderately lower gold grades but considerably larger ore volumes than the similar type elsewhere. (3) The Carlin style gold deposits of China are identified by higher Au grades but evidently smaller sizes in comparison with their counterparts in western North America. (4) The volcanogenic (continental) style is similar to Sado epithermal veins in gold grade‐tonnage models and general characteristics while volcanogenic gold deposits of the oceanic subgroup contrast with Kuroko‐type deposits in the gold grade model. But the Chinese volcanogenic (oceanic) subtype (Palaeozoic age) shows similar higher gold grades to those of the Palaeozoic Kuroko‐type deposits elsewhere. (5) Porphyry and skarn gold deposits tend to have a large size but low grade. (6) Less than half of the Shandong Peninsula gold deposits are of ore volumes exceeding the 50th intercept of the relevant gold tonnage model, implying possible undiscovered gold deposits with a larger size in the peninsula. (7) In general, Chinese gold deposits of larger sizes tend to have lower gold grades in relation to gold grade models. (8) Gold grade‐tonnage models can be effectively influenced by how to include or exclude non‐economic gold resources in the modelling. Ore volumes of gold deposits actually to some extent depend on gold grades. Consequently, the way of including or excluding low‐grade values may effect a gold grade‐tonnage model and cause different interpretation of the modelling results. This is particularly true to the gold deposits, which generally show an inverse correlation between gold grade and tonnage. 相似文献
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西藏铁格隆南铜(金)矿床三维模型分析与深部预测 总被引：1，自引：1，他引：0
铁格隆南铜(金)矿床是近年来在班公湖-怒江成矿带西段多龙矿集区新发现的超大型Cu(Au-Ag)矿床。本文针对铁格隆南矿区深部找矿问题,以现代成矿地质理论和多元地学信息综合分析技术为支撑,以构建矿床找矿模型为指导,依托数据库技术、3S技术、三维建模与可视化技术及地质统计学理论与方法,开展基于矿产地质、地球物理、地球化学等成矿条件及找矿标志的三维地质实体建模与矿化异常三维空间重构,将铁格隆南矿床的预测评价研究拓展到三维空间,揭示了区内成矿地质特征、地球化学及地球物理异常表征,据此探讨了矿床的成因及矿体分布特征。并在此基础上,开展了矿区的地质-地球化学-地球物理综合信息分析与预测评价,以期减少单一信息多解性和成矿条件不确定性,为铁格隆南矿区深部找矿工作提供参考。研究结果表明:在地质找矿模型指导下,基于深部成矿空间三维结构重构基础上的三维地质、地球物理、地球化学异常信息提取与综合分析,可以有效的识别成矿地质体和矿致异常信息,实现深部矿产资源靶区空间定位预测,为深部找矿预测研究提供了新思路。综合分析结果显示铁格隆南矿床深部找矿潜力巨大。 相似文献
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ALEKSIS DREIMANIS 《Boreas: An International Journal of Quaternary Research》1993,22(2):110-112
Several subglacially formed short flutes show crescentic scours around the boulders at their proximal end and furrows along their sides. The crescentic scours and furrows are partly filled by sorted sand and gravel. and it is suggested here that they were formed by fast flowing, turbulent meltwater in the subglacial cavity where the flute was formed. 相似文献
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One‐dimensional thermal (1DT) modelling of an Acadian (Devonian) tectonothermal regime in southern Vermont, USA, used measured metamorphic pressures and temperatures and estimated metamorphic cooling ages based on published thermobarometric and geochronological studies to constrain thermal and tectonic input parameters. The area modelled lies within the Vermont Sequence of the Acadian orogen and includes: (i) a western domain containing garnet‐grade pre‐Silurian metasedimentary and metavolcanic rocks from the eastern flank of an Acadian composite dome structure (Rayponda–Sadawga Dome); and (ii) an eastern domain containing similar, but staurolite‐ or kyanite‐grade, rocks from the western flank of a second dome structure (Athens Dome), approximately 10 km farther east. Using reasonable input parameters based on regional geological, petrological and geochronological constraints, the thermal modelling produced plausible P–T paths, and temperature–time (T –t) and pressure–time (P–t) curves. Information extracted from P–T –t modelling includes values of maximum temperature and pressure on the P–T paths, pressure at maximum temperature, predicted Ar closure ages for hornblende, muscovite and K‐feldspar, and integrated exhumation and cooling rates for segments of the cooling history. The results from thermal modelling are consistent with independently obtained pressure, temperature and Ar cooling age data on regional metamorphism in southern Vermont. Modelling results provide some important bounding limits on the physical conditions during regional metamorphism, and indicate that the pressure contemporaneous with the attainment of peak temperature was probably as much as 2.5 kbar lower than the actual maximum pressure experienced by rocks along various particle paths. In addition, differences in peak metamorphic grade (garnet‐grade versus staurolite‐grade or kyanite‐grade) and peak temperature for rocks initially loaded to similar crustal depths, differences in calculated exhumation rates, and differences in 40Ar/39Ar closure ages are likely to have been consequences of variations in the duration of isobaric heating (or ‘crustal residence periods’) and tectonic unroofing rates. Modelling results are consistent with a regional structural model that suggests west to east younging of specific Acadian deformational events, and therefore diachroneity of attainment of peak metamorphic conditions and subsequent 40Ar/39Ar closure during cooling. Modelling is consistent with the proposition that regional variations in timing and peak conditions of metamorphism are the result of the variable depths to which rocks were loaded by an eastward‐thickening thrust‐nappe pile rooted to the east (New Hampshire Sequence), as well as by diachronous structural processes within the lower plate rocks of the Vermont Sequence. 相似文献
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Camille Contoux Sophie Violette Raffaella Vivona Patrick Goblet Delphine Patriarche 《Hydrogeology Journal》2013,21(3):545-557
The Albian aquifer of the Paris Basin (France) has been exploited since 1841 and shows drastic drawdown. A three-dimensional (3D) groundwater flow model is used to study the hydrodynamic response of the multi-layered aquifers to pumping activity in the Albian, at basin scale over 167 years. This 3D flow model uses geometry and hydrodynamic parameter distributions that are inherited from a genetic approach through basin modelling, the basin model creating a geometric pattern of hydrodynamic properties constrained by geological history. The paper aims to promote the use of the basin model approach (long time scale, 248 Ma) for the study of deep-aquifer response to anthropogenic perturbation (short time scale, 167 years) in situations for which hydrodynamic data are scarce but geological data are numerous. The results show that parameter distribution is insufficient to reproduce the Albian aquifer behaviour, notably highlighting a different meaning of the specific storage coefficient between basin modelling and groundwater-flow modelling. Dividing the storage coefficient by 100 and including available transmissivity data significantly improved the model/data comparison. The potential impact on a deep aquitard is then discussed. This study sheds light on the advantages and limitations of the basin model approach for groundwater-flow modelling in 3D. 相似文献
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J. R. ASHWORTH V. S. SHEPLEV V. V. KHLESTOV V. A. ANANYEV 《Journal of Metamorphic Geology》2004,22(9):811-824
In statistically optimised P–T estimation, the contributions to overall uncertainty from different sources are represented by ellipses. One source, for a diffusion‐controlled reaction at non‐equilibrium, is diffusion modelling of the reaction texture. This modelling is used to estimate ratios, Q, between free‐energy differences, ΔG, of reactions among mineral end‐members, to replace the equilibrium condition ΔG = 0. The associated uncertainty is compared with those already inherent in the equilibrium case (from end‐member data, activity models and mineral compositions). A compact matrix formulation is introduced for activity coefficients, and their partial derivatives governing error propagation. The non‐equilibrium example studied is a corona reaction with the assemblage Grt–Opx–Cpx–Pl–Qtz. Two garnet compositions are used, from opposite sides of the corona. In one of them, affected by post‐reaction Fe, Mg exchange with pyroxene, the problem of reconstructing the original composition is overcome by direct use of ratios between chemical‐potential differences, given by the diffusion modelling. The number of geothermobarometers in the optimisation is limited by near‐degeneracies. Their weightings are affected by strong correlations among Q ratios. Uncertainty from diffusion modelling is not large in comparison with other sources. Overall precision is limited mainly by uncertainties in activity models. Hypothetical equilibrium P–T are also estimated for both garnet compositions. By this approach, departure from equilibrium can be measured, with statistical uncertainties. For the example, the result for difference from equilibrium pressure is 1.2 ± 0.7 kbar. 相似文献
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LARGEST ALTYN TAGH LITHOSPHERIC SHEAR FAULT IN CENTRAL ASIA 总被引：1，自引：0，他引：1
《地学前缘》2000,(Z1)
LARGEST ALTYN TAGH LITHOSPHERIC SHEAR FAULT IN CENTRAL ASIA 相似文献