与陆相火山岩有关的铁、铜、金矿床成矿地质特征及矿床成因   总被引：5，自引：0，他引：5       下载免费PDF全文

马芳  蒋少涌 《地质找矿论丛》2005,20(4):233-241

文章对与陆相火山岩有关的浅成低温金矿、斑岩铜矿和玢岩铁矿产出的大地构造背景、火成岩性质和矿化蚀变特征、成矿流体以及成矿物质来源等方面进行了综述.三类矿床在成矿地质条件上各具特色,表现在:成矿构造背景上,斑岩铜矿和浅成低温金矿均以岛弧和活动大陆边缘为主,其次是陆内环境;而长江中下游玢岩铁矿的形成环境可能为陆内似裂谷环境.浅成低温金矿、斑岩铜矿及玢岩铁矿的主要围岩分别为中、酸性火山岩系、中酸性次火山岩及中基性次火山岩;围岩蚀变分别以硅化、钾化、钠化为特征.浅成低温金矿床成矿流体以低盐度、低温(200～300℃)为主;而斑岩铜矿中则主要是高温(400～800℃)高盐度的流体;玢岩铁矿成矿温度介于两者之间.从低硫亚类浅成热液矿床、高硫亚类浅成热液矿床到斑岩型矿床,流体中大气水含量逐渐减少,岩浆水含量逐渐增多.成矿物质来源上,Fe主要来源于赋矿的火山-次火山岩或原始岩浆,Cu,Au,S和Na等成矿物质的来源更为复杂,还可能来源于与岩浆无关的围岩,其他的可能还包括Cu,S的岩浆混合来源以及Na的高盐卤水来源.一些特殊的岩石类型,如埃达克岩、橄榄玄粗岩及碱性岩与陆相火山岩矿床有密切联系.  相似文献   

Iron oxidation state in lower mantle mineral assemblages: I. Empirical relations derived from high-pressure experiments     

C.A. McCammon  S. Lauterbach  F. Seifert  P.A. van Aken 《Earth and Planetary Science Letters》2004,222(2):435-449

The oxidation state of iron can significantly influence the physical and chemical properties of lower mantle minerals. To improve methods for estimation of Fe³⁺/∑Fe, synthetic assemblages of (Mg,Fe)(Si,Al)O₃ perovskite and (Mg,Fe)O ferropericlase were synthesised from oxide starting mixtures in Re or Fe capsules at 26 GPa and 1650-1850 °C using a multianvil press. (Mg,Fe)(Si,Al)O₃ majorite was also present in some of the run products. Both electron energy loss spectra (EELS) and Mössbauer spectra were measured for each run product, and a robust fitting method was developed for Mössbauer spectra using EELS results as a standard that enabled Fe³⁺/∑Fe of (Mg,Fe)(Si,Al)O₃ perovskite to be determined from Mössbauer spectra of multiphase assemblages. There is a close to linear variation between Fe³⁺/∑Fe and Al concentration in (Mg,Fe)(Si,Al)O₃ perovskite, independent of oxygen fugacity. The concentration of Fe³⁺ in (Mg,Fe)O increases with increasing iron concentration along curves of constant oxygen fugacity, where higher oxygen fugacity stabilises greater Fe³⁺ concentrations. Fe²⁺/Mg partition coefficients calculated from chemical composition data corrected for measured Fe³⁺/∑Fe showed values nearly identical within experimental error for all samples, and independent of Al concentration and oxygen fugacity. Simple empirical relations were derived to calculate Fe³⁺/∑Fe in (Mg,Fe)(Si,Al)O₃ perovskite and (Mg,Fe)O ferropericlase samples for which no Mössbauer or EELS data were available, and tested by applying them to calculation of Fe²⁺/Mg partition coefficients from literature data for (Mg,Fe)(Si,Al)O₃ perovskite-(Mg,Fe)O assemblages where only total iron concentrations had been measured. Results showed Fe²⁺/Mg partition coefficients that were equal to existing values within experimental error, hence confirming the validity of the empirical relations.  相似文献   

云南大红山铁矿床三维数学模型探讨   总被引：6，自引：0，他引：6  

黎应书  秦德先  蔡燕  陈爱兵  余阳先  普传杰  林小平 《矿物岩石地球化学通报》2004,23(4):332-335

为实现矿山的生产动态管理与矿床的三维可视化，应用地质统计学的理论和方法，尤其是应用能够反映区域化变量特征的变异函数，借助计算机和Micromine软件包，建立了大红山铁矿床的三维矿床数学模型。结果表明，该模型可以使矿山很清楚地了解矿体的形态、产状和化学组分分布特征等。此外，通过Kriging估值计算的储量与用传统方法计算的储量很接近。  相似文献   

云南省鹅头厂含铜铁矿床的地质特征、成矿作用和找矿前景探讨   总被引：1，自引：0，他引：1  

李志群  赫荣安  陈耀光  李伟中 《矿产与地质》2004,18(6):537-540

鹅头厂含铜铁矿床对位于康滇地轴中部，矿体受地层、岩性、构造、火山岩和次火山岩控制。分为三个矿群。矿石的矿物组成简单。矿石以富铁、含铜、高硫、高磷为特点。成矿地球化学研究显示出热水成矿特点，属火山热水沉积一次火山热液改造成因。矿区北部的铜厂箐一带具有很好的找矿前景。  相似文献   

铁屑粉煤灰微电解法预处理印染废水的研究   总被引：6，自引：3，他引：6  

谭明  邹东雷  赵晓波 《吉林大学学报(地球科学版)》2004,(Z1)

依据微电解的基本原理,采用铁屑粉煤灰对印染废水进行预处理。通过实验确定了影响因素和运行参数,即进水pH值为2.5~3.5,沉淀时pH值为8~8.5,反应时间为1h左右,粉煤灰/铁屑为2.0~3.0。印染废水的CODcr去除率和脱色率分别达到80%和92%以上。  相似文献   

An Objective Approach to the Definition of Some Mining Terms: Application to the Hasançelebi Iron Ore Deposit     

Yüksek  S.  Elevli  B.  Demirci  A. 《Natural Resources Research》2004,13(2):87-95

In the mining industry, definitions of terms such as geologic resource, geologic reserve, mineral resource, mineral, mineral reserve, ore, ore reserve, mineable reserve, and industrial minerals always have been debated, and have caused much confusion. The process of arriving at these definitions requires complicated exploration, calculation, and evaluation. Based on such work, the definitions about the mineral property will be distinctly different. The aims of this paper is to discuss and compare these definitions, and then contrast the differences among them in the example of the Hasançelebi iron are deposit, which is an important source of iron ore in Turkey.  相似文献   

Effects of size and origin of natural dissolved organic matter compounds on the redox cycling of iron in sunlit surface waters     

Laurence Meunier  Hansulrich Laubscher  Stephan J. Hug  Barbara Sulzberger 《Aquatic Sciences - Research Across Boundaries》2005,67(3):292-307

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Iron isotope fractionation during planetary differentiation   总被引：4，自引：0，他引：4  

Stefan Weyer  Ariel D. Anbar  Carsten Münker  Alan B. Woodland 《Earth and Planetary Science Letters》2005,240(2):251-264

The Fe isotope composition of samples from the Moon, Mars (SNC meteorites), HED parent body (eucrites), pallasites (metal and silicate) and the Earth's mantle were measured using high mass resolution MC-ICP-MS. These high precision measurements (δ⁵⁶Fe ≈ ± 0.04‰, 2 S.D.) place tight constraints on Fe isotope fractionation during planetary differentiation.Fractionation during planetary core formation is confined to < 0.1‰ for δ⁵⁶Fe by the indistinguishable Fe isotope composition of pallasite bulk metal (including sulfides and phosphides) and olivine separates. However, large isotopic variations (≈ 0.5‰) were observed among pallasite metal separates, varying systematically with the amounts of troilite, schreibersite, kamacite and taenite. Troilite generally has the lightest (δ⁵⁶Fe ≈ − 0.25‰) and schreibersite the heaviest (δ⁵⁶Fe ≈ + 0.2‰) Fe isotope composition. Taenite is heavier then kamacite. Therefore, these variations probably reflect Fe isotope fractionation during the late stage evolution and differentiation of the S- and P-rich metal melts, and during low-temperature kamacite exsolution, rather than fractionation during silicate-metal separation.Differentiation of the silicate portion of planets also seems to fractionate Fe isotopes. Notably, magmatic rocks (partial melts) are systematically isotopically heavier than their mantle protoliths. This is indicated by the mean of 11 terrestrial peridotite samples from different tectonic settings (δ⁵⁶Fe = + 0.015 ± 0.018‰), which is significantly lighter than the mean of terrestrial basalts (δ⁵⁶Fe = + 0.076 ± 0.029‰). We consider the peridotite mean to be the best estimate for the Fe isotope composition of the bulk silicate Earth, and probably also of bulk Earth. The terrestrial basaltic mean is in good agreement with the mean of the lunar samples (δ⁵⁶Fe = + 0.073 ± 0.019‰), excluding the high-Ti basalts. The high-Ti basalts display the heaviest Fe isotope composition of all rocks measured here (δ⁵⁶Fe ≈ + 0.2‰). This is interpreted as a fingerprint of the lunar magma ocean, which produced a very heterogeneous mantle, including the ilmenite-rich source regions of these basalts.Within uncertainties, samples from Mars (SNC meteorites), HED (eucrites) and the pallasites (average olivine + metal) have the same Fe isotope compositions as the Earth's mantle. This indicates that the solar system is very homogeneous in Fe isotopes. Its average δ⁵⁶Fe is very close to that of the IRMM-014 standard.  相似文献   

Elasticity of (Mg, Fe)(Si, Al)O₃-perovskite at high pressure     

Li Li  John P. Brodholt  Donald J. Weidner  Maria Alfredsson 《Earth and Planetary Science Letters》2005,240(2):529-536

The most abundant mineral on Earth has a perovskite crystal structure and a chemistry that is dominated by MgSiO₃ with the next most abundant cations probably being aluminum and ferric iron. The dearth of experimental elasticity data for this chemically complex mineral limits our ability to calculate model seismic velocities for the lower mantle. We have calculated the single crystal elastic moduli (c_ij) for (Mg, Fe^3 +)(Si, Al)O₃ perovskite using density functional theory in order to investigate the effect of chemical variations and spin state transitions of the Fe³⁺ ions. Considering the favored coupled substitution of Mg²⁺-Si^4 + by Fe³⁺-Al³⁺, we find that the effect of ferric iron on seismic properties is comparable with the same amount of ferrous iron. Ferric iron lowers the elastic moduli relative to the Al charge-coupled substitution. Substitution of Fe³⁺ for Al³⁺, giving rise to an Fe/Mg ratio of 6%, causes 1.8% lower longitudinal velocity and 2.5% lower shear velocity at ambient pressure and 1.1% lower longitudinal velocity and 1.8% lower shear velocity at 142 GPa. The spin state of the iron for this composition has a relatively small effect (< 0.5% variation) on both bulk modulus and shear modulus.  相似文献   

新疆哈密百灵山铁矿地质特征及成矿时代   总被引：2，自引：0，他引：2  

王龙生  李华芹  陈毓川  刘德权 《矿床地质》2005,24(3):264-269

文章总结了前人对百灵山铁矿的研究成果,并对已发表的地质图件进行了修正。首次对矿石中含矿石英脉中的流体包裹体进行了Rb_Sr等时线年龄测定,结果为(293±10)Ma,确定了该矿床的成矿时代为石炭纪末—二叠纪初。  相似文献