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1.
《地质科技情报》2016,(1)
东昆仑祁漫塔格地区是青海省重要的矽卡岩型铁多金属成矿带,小圆山矽卡岩型铁多金属矿位于青海祁漫塔格东段。利用LA-MC-ICP-MS锆石U-Pb定年技术,获得小圆山铁多金属矿区与成矿关系密切的英云闪长岩加权平均年龄为(217.7±1.1)Ma(n=36,MSWD=2.5),厘定其形成时代为晚三叠世,属印支晚期。岩石地球化学研究表明,英云闪长岩为准铝质高钾钙碱性系列岩石。岩石明显富集大离子亲石元素(Rb、K)、LREE和活泼的不相容元素(如U、Th),相对亏损高场强元素(如Nb、Ta、P、Zr、Ti),显示了轻稀土元素强烈富集的右倾式稀土元素配分型式,具有弱的负Eu异常。青海祁漫塔格地区已有的年代学资料和区域地质构造演化特征综合表明,小圆山英云闪长岩可能形成于后碰撞构造阶段,为区域东昆仑造山带晚古生代-早中生代构造旋回的产物。 相似文献
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狼娃山铁矿位于红石山蛇绿岩带南侧,矿体产于下石炭统白山组火山凝灰岩中,属火山岩型矿床。因前人对于该矿床的基础地质研究少之又少,因此对于矿床的勘探和进一步找矿带来了一定的难度。笔者从矿区的基础地质入手,通过对矿区围岩、蚀变岩和矿体的微量元素、稀土元素和S同位素的研究,探讨其矿床成因。结果表明,从围岩到蚀变岩,再到矿体,较之于地壳更加富集于地幔的微量元素(Sc、Co、Ni、Cu)均数倍乃至于数百倍的富集于矿石中,而相对富集于地壳的元素(Zr、Nb、Ta、Th)则更富集于围岩和蚀变岩。根据围岩、蚀变岩和矿体的稀土元素含量及其配分图,发现围岩和蚀变岩为右倾型,并具有明显负Eu异常,而矿石较特殊亏损轻稀土并具有显著的正Eu异常,S同位素结果显示"34S值的变化范围为+0.6‰~+3.4‰,平均值为+1.82‰。北山地区在早石炭世时曾发生大规模的岩浆事件,而同时期区域上为岛弧环境,综上结果表明,成矿物质来源于亏损上地幔部分熔融的含矿岩浆,在近地表侵入下石炭统白山组沉积成矿,据此可认为,狼娃山铁矿为火山岩型铁矿。 相似文献
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新疆阿尔泰巴特巴克布拉克铁矿床矽卡岩矿物特征及其地质意义 总被引：2，自引：2，他引：0
巴特巴克布拉克铁矿床为在新疆阿尔泰新发现的中型铁矿床,赋存于上志留统—下泥盆统康布铁堡组变质火山-沉积岩系中,近矿围岩为石榴子石矽卡岩、角闪斜长变粒岩和浅粒岩,矿体呈似层状、透镜状及不规则状,周围发育大量矽卡岩矿物。文章对矽卡岩矿物进行了研究,电子探针分析结果显示,石榴子石端员组分为钙铁榴石-钙铝榴石系列,辉石端员组分以透辉石-钙铁辉石为主,角闪石端员组分以铁镁钙闪石为主。研究表明,矿区矽卡岩为交代成因矽卡岩。通过矿床地质及矿物成因研究,认为该矽卡岩是由岩浆热液交代火山岩所形成,磁铁矿的富集成矿与矽卡岩的退化蚀变密切相关。 相似文献
5.
为探讨九星铁矿床的成矿与围岩(赋矿地层)的关系,系统采集了九星铁矿床赋矿变质围岩(绿泥石片岩和绿泥石千枚岩)样品进行元素地球化学分析。结果表明,两类赋矿变质围岩有如下特点:高硅铝、富钾镁且碱质总量偏低;富集大离子亲石元素,亏损高场强元素;轻稀土相对富集,重稀土相对亏损,轻重稀土分馏明显,具有Eu负异常与弱Ce正异常。赋矿变质围岩的原岩为铁质泥岩及纯泥质岩,沉积原岩物源主要为酸性火山岩区的长英质物源或长英质与基性岩混合物源,构造背景为被动大陆边缘。稀土元素示踪结果显示九星铁矿床磁铁矿与围岩稀土元素配分特征基本一致,综合分析认为九星铁矿床的成矿物质主要来源于围岩(赋矿地层)。 相似文献
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新疆阿尔泰南缘巴利尔斯铁矿床稀土元素地球化学研究 总被引：1，自引：0，他引：1
巴利尔斯铁矿是阿尔泰南缘麦兹盆地新近发现的中型铁矿床。赋存于上志留—下泥盆统康布铁堡下亚组第二岩性段变粒岩、浅粒岩及斜长角闪岩中, 矿体及其周围发育大量矽卡岩矿物。本文对矿体围岩、矽卡岩矿物和矿石进行了稀土元素地球化学研究, 结果表明磁铁矿矿石、矽卡岩与围岩斜长角闪岩的REE特征具有相似性, 暗示磁铁矿矿石与矽卡岩具有亲缘性, 斜长角闪岩可能提供部分成矿物质。矽卡岩和矿石发育Eu正异常及所有矿石的负Ce异常, 表明铁成矿作用发生在高温氧化环境。 相似文献
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蒙库铁矿床是一个以下泥盆统斜长角闪变粒岩(原岩为火山岩)为围岩的大型矽卡岩型矿床,矽卡岩矿物组合为辉石、石榴子石和方柱石,退化蚀变岩的组成矿物为角闪石、绿帘石、绿泥石、磷灰石等。电子探针分析结果表明,矽卡岩矿物中单斜辉石以透辉石为主,仅存在少量普通辉石;石榴子石端员组分以钙铁榴石为主,伴以少量钙铝榴石和锰铝榴石;角闪石属于单斜角闪石中的阳起石。蒙库铁矿床的矽卡岩与正常的矽卡岩矿床形成方式不同,不是中酸性岩浆与碳酸盐地层接触交代的产物,而是由热流体沿裂隙交代火山变质岩形成的。 相似文献
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基于砂岩岩心样品元素地球化学资料对莺歌海盆地东方区上中新统黄流组一段海底扇砂体的源岩类型、风化程度及构造背景进行了分析。以平均大陆上地壳(UCC)对主量元素做标准化处理,结果显示SiO2略显示富集,CaO和TiO2仅4个样品相对富集,其他大部分样品主量元素均显示相对亏损特征。稀土元素配分模式呈现轻稀土元素富集、重稀土元素亏损特征,轻稀土元素与重稀土元素比值介于7.58~11.12之间(平均9.28),(La/Yb)N介于7.15~13.55之间(平均11.04),(Gd/Yb)N介于1.34~2.07之间(平均1.81),Eu元素显示负异常,δEu介于0.48~0.70之间(平均0.64),且样品的配分模式与UCC相似,Al_2O_3/TiO_2=11.03~17.02(平均14.48),以及w(K_2O)-w(Rb)和w(TiO_2)-w(Zr)图解均表明源岩为中性-长英质火山岩。化学蚀变指数(CIA)值(56.48~68.97)、长石蚀变指数(PIA)值(58.90~75.78)、A-CN-K图解表明黄流组砂岩经历了中等强度的风化作用。Th-Sc-Zr/10三角图、w(TiO_2)-w(Fe_2O_3+MgO)判别图解以及主量元素判别图解均显示源区具有碰撞环境特征(主动大陆边缘或大陆岛弧),且稀土元素配分模式与越南物源相似。综合可知,西部昆嵩隆起的中性-长英质火山岩为研究区主要物质来源。 相似文献
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安徽姑山矿浆型铁矿床Fe同位素初步研究 总被引：2，自引：0，他引：2
文章报道了宁芜矿集区内姑山矿浆型铁矿床中的铁氧化物、辉石闪长玢岩和赋矿围岩的Fe同位素组成,其δ57Fe的总体分布范围为-0.05‰~0.79‰。结果显示,姑山铁矿床的铁氧化物赤铁矿和镜铁矿均比硅酸盐岩浆结晶产物(辉石闪长岩)富集重的Fe同位素,并且硅酸盐岩浆的Fe同位素组成比已报道的火山岩的平均Fe同位素组成更富集轻的Fe同位素,表明在岩浆不混溶的过程中Fe同位素发生了分馏,富铁熔体相对富集重的Fe同位素,而硅酸盐熔体相对富集轻的Fe同位素;相对于赋矿地层(黄马青组石英砂岩)和辉石闪长玢岩,赤铁矿和镜铁矿更富集重的Fe同位素,围岩地层和闪长岩岩体则富集轻的Fe同位素。因此,姑山铁矿床的铁质不大可能来自于地层或闪长玢岩岩体,而主要来源于深部岩浆房。 相似文献
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拉伊克勒克矿床是在第四系覆盖区新发现的隐伏斑岩铜(钼)矿床。采用LA-ICP-MS技术,对赋矿岩体英云闪长岩中的锆石和矿石中的辉钼矿分别进行锆石U-Pb同位素、Re-Os同位素和锆石Hf同位素测定及相应的研究。测得锆石U-Pb年龄为421.8±2.5Ma,辉钼矿Re-Os模式年龄为409.1±2.6Ma,表明拉伊克勒克斑岩铜(钼)矿床形成于晚志留世—早泥盆世,与琼河坝地区主要斑岩矿床大规模成矿时间一致。英云闪长岩属过铝质-钙碱性系列花岗岩类,岩体具有较高的铝钙含量,K_2O/Na_2O值普遍偏低,介于0.16~0.29之间;稀土元素配分曲线呈现右倾特征,稀土元素总量较低,轻稀土元素相对富集,负Eu异常不明显。在微量元素原始地幔标准化蛛网图上,高场强元素Th、Nb、Ta、P、Ti等相对亏损,大离子亲石元素Rb、Ba、U、K、Sr等相对富集。同时岩体具有高的正ε_(Hf)(t)值(10.98~15.01)和年轻的模式年龄(451~708Ma),暗示英云闪长岩体是大陆边缘弧环境下大洋板片熔融的产物,对进一步明确琼河坝地区斑岩型矿床的成矿环境和找矿方向具有重要意义。 相似文献
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Most sulfide-rich magmatic Ni-Cu-(PGE) deposits form in dynamic magmatic systems by partial melting S-bearing wall rocks with variable degrees of assimilation of miscible silicate and volatile components, and generation of barren to weakly-mineralized immiscible Fe sulfide xenomelts into which Ni-Cu-Co-PGE partition from the magma. Some exceptionally-thick magmatic Cr deposits may form by partial melting oxide-bearing wall rocks with variable degrees of assimilation of the miscible silicate and volatile components, and generation of barren Fe ± Ti oxide xenocrysts into which Cr-Mg-V ± Ti partition from the magma. The products of these processes are variably preserved as skarns, residues, xenoliths, xenocrysts, xenomelts, and xenovolatiles, which play important to critical roles in ore genesis, transport, localization, and/or modification. Incorporation of barren xenoliths/autoliths may induce small amounts of sulfide/chromite to segregate, but incorporation of sulfide xenomelts or oxide xenocrysts with dynamic upgrading of metal tenors (PGE > Cu > Ni > Co and Cr > V > Ti, respectively) is required to make significant ore deposits. Silicate xenomelts are only rarely preserved, but will be variably depleted in chalcophile and ferrous metals. Less dense felsic xenoliths may aid upward sulfide transport by increasing the effective viscosity and decreasing the bulk density of the magma. Denser mafic or metamorphosed xenoliths may also increase the effective viscosity of the magma, but may aid downward sulfide transport by increasing the bulk density of the magma. Sulfide wets olivine, so olivine xenocrysts may act as filter beds to collect advected finely dispersed sulfide droplets, but other silicates and xenoliths may not be wetted by sulfides. Xenovolatiles may retard settling of – or in some cases float – dense sulfide droplets. Reactions of sulfide melts with felsic country rocks may generate Fe-rich skarns that may allow sulfide melts to fractionate to more extreme Cu-Ni-rich compositions. Xenoliths, xenocrysts, xenomelts, and xenovolatiles are more likely to be preserved in cooler basaltic magmas than in hotter komatiitic magmas, and are more likely to be preserved in less dynamic (less turbulent) systems/domain/phases than in more dynamic (more turbulent) systems/domains/phases. Massive to semi-massive Ni-Cu-PGE and Cr mineralization and xenoliths are often localized within footwall embayments, dilations/jogs in dikes, throats of magma conduits, and the horizontal segments of dike-chonolith and dike-sill complexes, which represent fluid dynamic traps for both ascending and descending sulfides/oxides. If skarns, residues, xenoliths, xenocrysts, xenomelts, and/or xenovolatiles are present, they provide important constraints on ore genesis and they are valuable exploration indicators, but they must be included in elemental and isotopic mass balance calculations. 相似文献
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针对兖州煤田下组煤深部开采受奥灰高承压水威胁以及当地大型煤化工企业生产用水量大的现状,在已进行的水文地质勘探及放水试验基础上,评价奥灰富水性,并采用有限差分法进行奥灰疏水降压数值模拟研究,提出水煤共采观点。研究结果表明:兖州煤田深部奥灰水压高,合理布置水煤共采孔,可以实现奥灰水位的有效疏降,疏降中心区水位最大降深可达110 m,突水系数显著下降,提高了下组煤开采的安全性;同时可提供煤化工43200 m3/d的供水量,能达到可持续的、水资源保护性的供水效果,实现下组煤的水煤共采。 相似文献
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《Chemical Geology》2007,236(1-2):13-26
We examined the coprecipitation behavior of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides under two different fluoride forming conditions: at < 70 °C in an ultrasonic bath (denoted as the ultrasonic method) and at 245 °C using a Teflon bomb (denoted as the bomb method). In the ultrasonic method, small amounts of Ti, Mo and Sn coprecipitation were observed with 100% Ca and 100% Mg fluorides. No coprecipitation of Ti, Mo, Sn and Sb in Ca–Al–Mg fluorides occurred when the sample was decomposed by the bomb method except for 100% Ca fluoride. Based on our coprecipitation observations, we have developed a simultaneous determination method for B, Ti, Zr, Nb, Mo, Sn, Sb, Hf and Ta by Q-pole type ICP-MS (ICP-QMS) and sector field type ICP-MS (ICP-SFMS). 9–50 mg of samples with Zr–Mo–Sn–Sb–Hf spikes were decomposed by HF using the bomb method and the ultrasonic method with B spike. The sample was then evaporated and re-dissolved into 0.5 mol l− 1 HF, followed by the removal of fluorides by centrifuging. B, Zr, Mo, Sn, Sb and Hf were measured by ID method. Nb and Ta were measured by the ID-internal standardization method, based on Nb/Mo and Ta/Mo ratios using ICP-QMS, for which pseudo-FI was developed and applied. When 100% recovery yields of Zr and Hf are expected, Nb/Zr and Ta/Hf ratios may also be used. Ti was determined by the ID-internal standardization method, based on the Ti/Nb ratio from ICP-SFMS. Only 0.053 ml sample solution was required for measurement of all 9 elements. Dilution factors of ≤ 340 were aspirated without matrix effects. To demonstrate the applicability of our method, 4 carbonaceous chondrites (Ivuna, Orgueil, Cold Bokkeveld and Allende) as well as GSJ and USGS silicate reference materials of basalts, andesites and peridotites were analyzed. Our analytical results are consistent with previous studies, and the mean reproducibility of each element is 1.0–4.6% for basalts and andesites, and 6.7–11% for peridotites except for TiO2. 相似文献
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Hirokazu Fujimaki 《Contributions to Mineralogy and Petrology》1986,94(1):42-45
Concentration ratios of Hf, Zr, and REE between zircon, apatite, and liquid were determined for three igneous compositions: two andesites and a diorite. The concentration ratios of these elements between zircon and corresponding liquid can approximate the partition coefficient. Although the concentration ratios between apatite and andesite groundmass can be considered as partition coefficients, those for the apatite in the diorite may deviate from the partition coefficients. The HREE partition coefficients between zircon and liquid are very large (100 for Er to 500 for Lu), and the Hf partition coefficient is even larger. The REE partition coefficients between apatite and liquid are convex upward, and large (D=10–100), whereas the Hf and Zr partition coefficients are less than 1. The large differences between partition coefficients of Lu and Hf for zircon-liquid and for apatite-liquid are confirmed. These partition coefficients are useful for petrogenetic models involving zircon and apatite. 相似文献
17.
The distribution of Cu, Co, As and Fe was studied downstream from mines and deposits in the Idaho Cobalt Belt (ICB), the largest Co resource in the USA. To evaluate potential contamination in ecosystems in the ICB, mine waste, stream sediment, soil, and water were collected and analyzed for Cu, Co, As and Fe in this area. Concentrations of Cu in mine waste and stream sediment collected proximal to mines in the ICB ranged from 390 to 19,000 μg/g, exceeding the USEPA target clean-up level and the probable effect concentration (PEC) for Cu of 149 μg/g in sediment; PEC is the concentration above which harmful effects are likely in sediment dwelling organisms. In addition concentrations of Cu in mine runoff and stream water collected proximal to mines were highly elevated in the ICB and exceeded the USEPA chronic criterion for aquatic organisms of 6.3 μg/L (at a water hardness of 50 mg/L) and an LC50 concentration for rainbow trout of 14 μg/L for Cu in water. Concentrations of Co in mine waste and stream sediment collected proximal to mines varied from 14 to 7400 μg/g and were highly elevated above regional background concentrations, and generally exceeded the USEPA target clean-up level of 80 μg/g for Co in sediment. Concentrations of Co in water were as high as in 75,000 μg/L in the ICB, exceeding an LC50 of 346 μg/L for rainbow trout for Co in water by as much as two orders of magnitude, likely indicating an adverse effect on trout. Mine waste and stream sediment collected in the ICB also contained highly elevated As concentrations that varied from 26 to 17,000 μg/g, most of which exceeded the PEC of 33 μg/g and the USEPA target clean-up level of 35 μg/g for As in sediment. Conversely, most water samples had As concentrations that were below the 150 μg/L chronic criterion for protection of aquatic organisms and the USEPA target clean-up level of 14 μg/L. There is abundant Fe oxide in streams in the ICB and several samples of mine runoff and stream water exceeded the chronic criterion for protection of aquatic organisms of 1000 μg/L for Fe. There has been extensive remediation of mined areas in the ICB, but because some mine waste remaining in the area contains highly elevated Cu, Co, As and Fe, inhalation or ingestion of mine waste particulates may lead to human exposure to these elements. 相似文献
18.
E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
19.
Todd Dunn 《Contributions to Mineralogy and Petrology》1987,96(4):476-484
The crystal/liquid partition coefficients of Lu, Hf, Ti, Mn and Ca have been measured between olivine, clinopyroxene and basaltic melt. The Ti, Mn, and Ca partition coefficients were determined at natural abundance levels. The Lu and Hf partition coefficients were determined at doping levels ranging from 0.5 to 1.5 wt% “trace element” as oxide in order to allow analysis by electron microprobe. Olivine/liquid partition coefficients for Lu, Hf, Ti, Mn, and Ca were determined at 1 bar and temperatures from 1150 to 1177° C. Clinopyroxene/liquid partition coefficients were determined for Lu, Hf, Ti, and Mn at pressures of 10, 15, and 20 kbars and temperatures from 1250 to 1290° C. The olivine/liquid partition coefficients of Hf, Lu, Ti, and Ca are small. D(Hf-ol) is zero within the analytical uncertainty. Both D(Lu-ol) and D(Mn-ol) decrease with increasing temperature, but D(Ti-ol) and D(Ca-ol) are constant over the narrow temperature range studied. The partition coefficient results are summarized below.
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20.
Stratiform quartz-sulphide lodes in Ingladhal occur in a typical Precambrian green-stone-belt environment comprising metabasalts, tuff, chert and cherty iron-sulphide formation. Unusually high cobalt contents of metavolcanics and of sulphide minerals in orebodies suggest a consanguinity between ores and rocks. 90% of total nickel, 70% of total cobalt but only 30% of total copper in rocks occur in silicate phases and thus indicate an early separation of copper from cobalt and nickel. Unusually high non-sulphide copper in barren bedded cherts implies availability of Cu-rich solution prior to their lithification. Pyrite in sediments, in volcanics, and in orebodies is characterized by a distinctive pattern of Co-Ni distribution in each case. Partitioning of Co and Ni between coexisting sulphide pairs is complex, but gross equilibrium is indicated. Very high trace metal content of orebody pyrite sharply contrasts with very low such values in pyrite from adjacent sediments and points to a higher temperature of formation of orebodies. 相似文献
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