共查询到20条相似文献，搜索用时 62 毫秒
1.
华南是我国重要的钨锡成矿区。本文围绕华南与花岗岩有关的大规模钨锡成矿作用,系统收集了区内130余个主要矿床的地质和同位素年代学资料,初步总结了与花岗岩有关大规模钨锡矿床的主要类型和时空分布特征。统计结果表明,矽卡岩型和石英脉型是华南最重要的钨成矿类型,而矽卡岩型和锡石硫化物型(或碳酸盐岩交代型)是华南最主要的锡成矿类型。华南与花岗岩有关钨锡成矿作用具有多时代特点,但大规模成矿均集中于燕山期。以南岭和赣北成矿带为主要代表的钨成矿作用主要集中爆发于晚侏罗世至早白垩世早期(160～120Ma),而右江盆地晚白垩世(110～80 Ma,峰期为90～80 Ma)和南岭成矿带晚侏罗世(160～150 Ma)锡矿床则共同构成了华南最主要的锡成矿作用。多种不同矿化或金属类型在同一矿床或矿田尺度上组合产出是华南与花岗岩有关钨锡矿床的重要特征之一,对指导找矿具有重要意义。对此,文章结合华南地区近年来的一些重要成矿机制研究成果和找矿勘查进展,分别以瑶岗仙、川口、茅坪、柿竹园、大厂和个旧等矿床或矿田为例,论述了华南与花岗岩有关大规模钨锡成矿作用的几种成矿模式和找矿方向。此外,本文在钨、锡成矿花岗岩的岩石学、地... 相似文献
2.
赣南兴国县张家地钼钨矿床成岩成矿时代及地质意义 总被引：1，自引：0，他引：1
地处EW向南岭成矿带和NE向武夷山成矿带叠置部位的赣南兴国-宁都钨锡矿集区产有多处不同矿化类型的钨锡多金属矿床,但总体研究程度较低。本文基于详细野外地质调查,重点开展了张家地钼钨矿床的高精度成岩成矿年代学研究,并探讨了区域钨锡矿床成岩成矿时空分布及地球动力学背景。张家地钼钨矿化产于花岗岩与震旦纪浅变质细碎屑岩的内、外接触带,包括石英脉型(王泥排矿段)和云英岩型(刘家庄矿段)两种矿化类型。利用SHRIMP锆石U-Pb法,获得张家地钼钨矿区似斑状中细粒黑云母花岗岩的年龄为154.1±1.8Ma;利用辉钼矿Re-Os法,获得王泥排矿段石英脉型矿体的辉钼矿Re-Os等时线年龄为158.4±3.1Ma、加权平均年龄为157.7±1.4Ma,刘家庄矿段云英岩型矿体的辉钼矿Re-Os等时线年龄为161.9±3.2Ma、加权平均年龄为157.9±1.6Ma,厘定矿床成岩成矿时代为晚侏罗世,对应于华南中生代第二次大规模成矿作用。石英脉型和云英岩型矿体中辉钼矿的铼含量均较低(9.58×10-6~22.65×10-6),表明成矿物质以壳源为主;综合分析区域最新年代学数据资料,表明钨锡矿床成岩成矿具多期性,主要集中在240~210Ma、170~150Ma和130~90Ma,以赣南和湘南为中心,钨锡矿床向四周成矿年龄均呈变小趋势。燕山期钨锡大规模成岩成矿作用主要形成于华南中生代岩石圈伸展-减薄时期的侏罗纪板内拉张的地球动力学背景。 相似文献
3.
江西彭山锡多金属矿集区位于江西省德安县,处于钦杭成矿带东段靠扬子板块一侧,是扬子板块东南缘地区一个重要的锡多金属矿集区。目前该地区尚缺乏精确可靠的成矿年代学资料。本文应用LA-MC-ICP-MS微区原位U-Pb同位素测年技术,对矿集区内尖峰坡矿床中锡石样品进行了研究,获得尖峰坡锡矿的206Pb/207Pb-238U/207Pb等时线年龄129.7±2.5Ma(N=31,MSWD=5.5),207Pb/206Pb-238U/206Pb谐和年龄为128.3±2.5Ma(N=31,MSWD=7.6),表明尖峰坡矿区锡成矿作用主要发生在早白垩世,与已报道的彭山地区燕山期花岗岩的成岩年龄相一致。紧密的时间以及空间关系显示燕山晚期岩浆-热液活动对形成彭山锡多金属矿集区的大规模成矿作用至关重要。对华南地区锡钨区域成矿年代学对比表明,扬子板块东南缘的锡钨成矿带均形成于早白垩世(146~124Ma),这与其北侧的长江中下游成矿带九瑞-鄂东南铜多金属矿集区的成岩成矿时代相同,而明显不同于南岭地区晚侏罗世(160~150Ma)以及滇东南-桂西北地区晚白垩世(98~76Ma)的锡钨成矿作用,说明扬子板块东南缘具有与南岭以及滇东南-桂西北地区不同的锡钨成矿背景,而应与长江中下游地区的构造岩浆作用事件统一来开展深入研究。 相似文献
4.
南岭成矿带是全球最重要的钨锡成矿带之一,区内钨锡成矿条件优渥,是开展钨锡找矿勘查的重要目标区。然而如何开展钨锡找矿工作,尤其是在已有矿床周缘圈定成矿远景区,是钨锡成矿作用研究以及找矿勘查工作关注的重要科学问题。双园冲矿床位于南岭成矿带中西段,处于荷花坪与柿竹园两个大型锡钨多金属矿田中间,并与两个矿田处于同一构造体系,但目前对该矿床的研究程度较低,由此也制约了其矿床成因研究及该区的找矿部署。本次研究获得双园冲云英岩化花岗岩的锆石和独居石原位LA-ICP-MS U-Pb年龄分别为161.2±2.5Ma和157.1±1.8Ma,与云英岩型矿石中锡石原位LA-ICP-MS U-Pb年龄(158.9±2.9Ma)一致,二者均形成于晚侏罗世,表明其具有密切的成因关系,这一年龄也与南岭成矿带钨锡成矿大爆发时代(150-160Ma)一致。综合对比双园冲锡矿及与其空间相邻的柿竹园和荷花坪锡多金属矿田特征显示,三者成岩成矿时代一致,岩体侵位和矿体分布均受NE向断裂控制,矿体也均赋存于中-上泥盆统碳酸盐岩地层中,并且成矿花岗岩具有相似的岩石学特征和岩浆源区。综合以上信息,本文提出三个矿床可能形成于同一次岩浆热液活动,成矿岩体可能来自地壳深部同一个大岩浆房,柿竹园和荷花坪之间的区域具有发育晚侏罗世花岗岩体及相关钨锡矿的较大潜力。根据双园冲锡矿及其周缘大型锡钨矿床浅部脉状Pb-Zn-Fe-Mn矿化和深部矽卡岩-云英岩型Sn-W矿化的特征,提出研究区乃至整个南岭地区浅部脉状Pb-Zn-Fe-Mn矿化是深部Sn-W找矿勘查的有利部位。 相似文献
5.
华南地区是我国重要的战略矿产资源基地,以发育大规模多时代、多旋回花岗岩和独特的中生代铜钼钨锡铌钽铍铀等大规模稀有金属和有色金属成矿作用而闻名于世。华南地区稀有金属（W-Sn-Nb-Ta-Li-Be）成矿作用主要与高度分异演化的花岗岩密切相关。稀有金属矿床的分布受区域性断裂控制,主要集中于南岭地区和钦-杭大断裂两侧。成矿类型主要有花岗岩型、伟晶岩型、云英岩型、石英脉型、火山岩型、接触交代岩型（包括矽卡岩型和条纹岩型）。花岗岩型稀有金属矿床主要沿钦-杭大断裂两侧分布;伟晶岩型矿床主要分布在钦-杭大断裂花岗岩型矿床的外侧,以及邵武-河源断裂和政和-大埔断裂之间;接触交代型（含条纹岩型）稀有金属主要呈东西向分布于南岭地区,石英脉型和云英岩型稀有金属矿床主要与该地区的石英脉型钨矿有成因联系;火山岩型稀有金属矿床主要分布于政和-大埔断裂以东的东南沿海火山岩地区。华南稀有金属成矿可以分为7个阶段,分别是志留纪（424~420Ma）、早三叠世（248~244Ma）、晚三叠世（220~214Ma）、晚侏罗世（160~150Ma）、晚侏罗世-早白垩世（150~140Ma）、早白垩世（135~125Ma）和早白垩世-晚白垩世（105~90Ma）等。在每个时间段内,成矿时间相对集中。大规模稀有金属成矿主要集中于早白垩世。在不同成矿尺度,稀有金属矿化具有明显金属分带特征,且与有色金属矿化具有明显的成因关系;不同金属组合的稀有金属矿床具有不同的岩浆热液演化历史。地壳物质的部分熔融、持续能量供给,以及有利于岩浆高度分异演化的大型伸展构造是形成稀有金属矿床的重要条件。本文认为早白垩世（135~125Ma）是华南地区稀有金属大规模成矿的时期,该时期不仅成矿强度大,而且成矿类型多样,代表了华南中生代岩石圈大规模减薄或者全面裂解的峰期。 相似文献
6.
长江中下游成矿带庐枞矿集区首例钨矿床成岩成矿时代及其意义 总被引：8，自引：7，他引：1
庐枞矿集区是长江中下游成矿带中重要的铁铜多金属成矿区之一。2014年在矿集区北部首次勘探发现了东顾山钨多金属矿床,其成矿与隐伏黑云母花岗岩体关系密切。东顾山矿床的矿床地质特征和成矿岩浆岩明显不同于该矿集区内已知的斑岩型铜金矿床和玢岩型铁矿床有关的岩浆岩。本次工作在详细野外地质工作的基础上,开展了东顾山钨多金属矿床地质特征、成矿岩体的岩石学和成岩成矿时代研究。研究表明,东顾山矿床为矽卡岩型钨多金属矿床,其锆石LA ICP-MS U-Pb定年结果为99.7±1.5Ma~99.9±1.7Ma,与钨矿化形成于同一期岩浆热液活动的辉钼矿的Re-Os定年结果为97.22±0.77Ma,成岩成矿时代相近,表明东顾山钨多金属矿床的成矿作用与东顾山岩体几乎同时形成,二者具有密切的成因联系。通过与区域成岩成矿时代的对比,本文首次提出庐枞矿集区内存在100Ma左右的成岩成矿事件,在成矿时代和矿床类型上明显区别于成矿带先存的140Ma的斑岩-矽卡岩型铜矿床和130Ma的玢岩型铁矿床,是长江中下游成矿带新的一期成矿作用产物,据此将成矿带的燕山期成矿时代范围重新确定在145~97Ma之间,说明长江中下游成矿带存在与华南中生代第三次大规模成矿作用对应的伸展地球动力背景下的成矿事件。东顾山钨多金属矿床为下一步在庐枞矿集区及区域上开展100Ma左右的钨多金属矿床找矿勘探提供了重要的线索,也为区域成岩成矿作用的动力学背景进一步深入研究提出了新的课题。 相似文献
7.
塘唇钨(锡)矿是近年来新发现的一个具有大型规模找矿潜力的石英脉型矿床.矿床产于粤东龙窝花岗闪长岩岩体西部外接触带,赋矿地层为下侏罗统金鸡组碎屑岩,该层位是南岭及邻区石英脉型钨锡矿的最新赋矿地层.在详细的野外地质调查基础上,对矿床含钨石英脉中的白云母进行40Ar-39Ar测年,获得白云母40Ar-39Ar坪年龄为150±1 Ma,等时线年龄为149±2 Ma(MSWD=1.20),它们在误差范围内一致,为南岭地区燕山早期大规模成岩成矿作用高峰期的产物.塘唇钨(锡)矿的发现,不仅拓宽了石英脉型钨锡矿的找矿视野,还有助于完善石英脉型钨锡矿成矿规律和成矿模式,对区域下一步找矿具有重要指导意义. 相似文献
8.
湖南界牌岭锡多金属矿位于南岭中部,主要矿化为大规模缓倾斜顺层分布的含矿云母黄玉蚀变岩和云母萤石蚀变岩型锡矿、铍矿以及萤石矿化。成矿地质体为碱长花岗斑岩,具有高硅、低钙、过铝特征,钠长石An值平均为0.11;∑REE平均值高达698.19×10-6,稀土元素配分曲线呈Eu轻度亏损的右倾型,同时富含成矿元素及挥发性元素,其中含F可达0.12%。锆石的SHRIMP U-Pb年龄为92±1Ma(MSWD=1.5)。综合对比南岭成矿带、右江成矿带主要矿床与界牌岭锡多金属矿床的地质地球化学特征,认为界牌岭的成矿地质体和成矿地质特征明显不同于南岭燕山早期相关的钨矿床,而与右江成矿带燕山晚期锡多金属成矿作用更为密切,是右江燕山晚期锡多金属成矿带的东延。 相似文献
9.
湘南中生代花岗质岩石成岩成矿的时限 总被引：30，自引：1，他引：29
位于南岭中段的湘南地区,中生代花岗质岩石广泛分布;该区W、Sn、Pb、Zn、Mo、Bi等金属矿床密集产出,很多钨、锡矿床达到大型、超大型规模,且找矿潜力巨大,构成一个世界级的有色金属矿集区。最近大量的同位素年代学研究表明,南岭中段钨、锡、铅锌等金属的成矿是一个爆发性、区域性的地质事件,成矿时间高度集中,成矿时限主要在150~160 Ma之间,与该区主要花岗岩的成岩时间相当吻合;对单个钨、锡矿床而言,其矿区的成岩、成矿存在着一种准同期性,即成矿与矿区花岗岩的成岩基本上是同时的、或稍晚于花岗岩的成岩作用。因此,该区中生代的花岗岩与钨锡成矿作用具有明显的时、空联系。南岭中段花岗岩大规模的侵入和钨、锡等金属的爆发性成矿均形成于一种岩石圈伸展减薄、地壳拉张的构造环境,可能与华南中生代第二幕岩石圈伸展事件密切相关。 相似文献
10.
《地质科技情报》2021,(5)
付家山(Cu-)W矿床是鄂东南地区新近发现的大型矽卡岩型矿床之一,成矿与花岗闪长斑岩关系密切。为了精确获得该矿床成岩成矿年龄,利用LA-ICP-MS锆石U-Pb和辉钼矿Re-Os同位素定年法对其进行了系统的成岩成矿年代学研究,并基于长江中下游成矿带晚中生代沉积地层及构造变形、地球物理和岩石地球化学等证据探讨了其成岩成矿构造背景。结果显示:花岗闪长斑岩锆石U-Pb加权平均年龄为(144±3)Ma,而辉钼矿Re-Os模式年龄为(146±2)Ma,成岩与成矿作用均形成于晚侏罗世-早白垩世。付家山(Cu-)W矿床形成时代与长江中下游地区大规模岩浆成矿事件时间一致,包括鄂东南地区在内的长江中下游地区的构造演化历史及最新的年代学数据表明,付家山(Cu-)W矿床极有可能形成于岩石圈伸展减薄构造背景。付家山等晚侏罗世-早白垩世矽卡岩型(Cu-)W矿床的发现及厘定指示了鄂东南矿集区具有良好的钨矿找矿前景。 相似文献
11.
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
12.
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
13.
《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
14.
15.
16.
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.
| T°C 相似文献
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
|
|---|