安徽庐枞盆地龙桥铁矿床中钴的赋存状态和空间分布规律

中国东部的长江中下游、莱芜、邯邢和临汾等矿集区中发育大量的矽卡岩型铁矿床,其中普遍伴生钴,部分矿床估算伴生钴资源量大于1万t,达到中型钴矿床的规模。已有研究表明,中国东部富钴矽卡岩型铁矿床的成矿时代相同,成矿特征相似,均为中国东部130Ma大规模成矿作用的产物,反映较大规模的铁钴成矿作用受统一的动力学背景控制。钴与其他伴生组分一样,其工业价值主要不取决于矿石中钴的含量,而取决于钴的赋存状态,因此开展矽卡岩型铁矿床中钴的赋存状态和分布规律研究具有重要的理论和实践意义。龙桥矽卡岩型铁矿床位于长江中下游成矿带,是目前发现的成矿带内伴生钴含量最高的矿床。矿床主矿体长1000m,成矿岩体位于矿体中部,黄铁矿分布范围广,距离岩体中心不同距离均有分布,是研究矽卡岩型铁矿床中钴赋存状态和空间分布规律的理想对象。本次研究在龙桥铁矿床勘探巷道-370m平面自西向东采集了9件含黄铁矿样品,黄铁矿主要呈浸染状-细脉状交代磁铁矿。研究表明,龙桥铁矿床中钴主要赋存在黄铁矿和磁铁矿中,其次为独立钴矿物(主要为辉砷钴矿)。黄铁矿的LA-ICP-MS微区微量元素分析结果表明,龙桥黄铁矿中Co(0.019×10~(-6)～5639×10~(-6))、Ni(0.025×10~(-6)～5798×10~(-6))和As(0.46×10~(-6)～14526×10~(-6))的含量均具有较大的变化范围,黄铁矿总体上具有边缘富钴、核部贫钴的特征,黄铁矿边部的钴含量是核部的100～1000倍。通过对LA-ICP-MS测试数据以及时间分辨率剖面的逐一对比,推测Co主要以类质同象形式替代Fe进入黄铁矿晶格。由于钴在黄铁矿中分布极不均匀,不同空间位置采集的黄铁矿样品中Co含量平均值和变化范围没有明显规律。本文通过类比,提出中国东部矽卡岩型铁矿床中钴矿物可能是普遍存在的,但以前受限于分析测试手段未能发现;如何在选矿过程中分离富集钴矿物和富钴黄铁矿,是矽卡岩型铁矿床硫精粉中钴回收利用的关键。     

Re-Os Isotopic Age of Molybdenite of the Jingren Deposit and its Mineralogical Significance of Magnetite,Pyrite and Chalcopyrite

The Jingren deposit is part of the Qimantage metallogenic belt within the eastern Kunlun orogenic belt, the largest metallogenic belt in Qinghai Province, northwestern China. Exploration data show that the metal resources of the Jingren deposit are greater than 93000 t in a mining area of 76.15 km2, which indicates significant exploration potential in the near future. Three W–E-trending faults, F1-3, dominate the extension of the mineralization zone, which consists of chalcopyrite, pyrite, magnetite, galena, sphalerite, and molybdenite as well as bismuth-bearing minerals. The deposit contains a large amount of late Triassic intrusive rocks, however, previous research did not reach a consensus on the timing or the origin of the mineralization owing to a lack of geochronological data and poor exposure conditions. In the present study, Re-Os isotopic dating from six molybdenite samples collected from a borehole of the granodiorite in the Jingren deposit using negative thermal ionization mass spectrometry(NTIMS) showed 187 Re and 187 Os concentrations of 0.26–4.40 ppm and 1.03–16.46 ppb, respectively, with an initial 187 Os/188 Os value of 0.06 ± 0.19. This proves that the Jingren deposit has a metallogenic age of(225 ± 4) Ma and is the product of united mineralization of the Qimantage metallogenic belt and that the Jingren deposit might actually be an Indosinian metallogeny. In addition, the Re content of these samples, at 0.42 ppm to 7.00 ppm shows that the mineralization was derived mainly from a crustal source. Furthermore, electron probe microanalysis(EPMA) conducted on chalcopyrite obtained from 22 metallic mineral samples revealed(Fe + Cu)/S ratios of 1.801–1.947 with an average of 1.852, which is lower than the ideal value(1.875). Besides, the main ore body formed in a relatively higher temperature environment than the surrounding rocks in the Jingren deposit. These data indicate that the Jingren deposit formed in a metallogenic environment at lower temperature. Moreover, according to the TiO2-Al2 O3-(MgO+ MnO) and TiO2-Al2 O3-MgO genetic classification diagram for magnetite, the Jingren deposit most likely belongs to the skarn family. In addition, the Co-Ni-As genetic classification diagram of the pyrite indicates sedimentary and skarn genetic characteristics.     

对柿竹园矽卡岩成因及其成矿作用的新认识

本文将报导柿竹园Ｗ，Ｓｎ，Ｍｏ，Ｂｉ矿床中矽卡岩矿物－石榴子石和辉石成分和石榴子石中熔融包裹体研究结果，对不同中段的１６块矽卡岩样品（９４％的标本采自第Ⅲ矿带）中的石榴子石和辉石进行了电子探针分析，共获得２３０个测点的数据，此外，还对上述中段大部分样品里的石榴子石和辉石进行了从边部到核心成分测定，共获得１３个样品的９７个测点数据，研究结果表明，绝大多数石榴子石属于含Ａｌｍ＋Ｓｐｓ＋Ｐｙｒ〈１３％（     

我国一些重要夕卡岩Pb-Zn多金属矿床的交代分带

在我国一些重要夕卡岩Ｐｂ－Ｚｎ多金属矿床中，交代矿化分带十分明显，主要表现为围绕侵入体接触带或热源中心向碳酸盐围岩方向１，呈现有规律的带状分布１。根据有关岩浆岩和矿化组合的不同，可大致划分为三个匀代分带序列，总的分带序列是：Ｆｅ（ＭＯ）－Ｆｅ－Ｓｎ－Ｓｎ（Ｗ）－Ｃｕ－Ｃｕ－Ｚｎ－Ｚｎ，Ｐｂ（Ａｇ）。     

铜官山铜矿床矽卡岩矿物中流体包裹体及子矿物的扫描电镜研究

通过对安徽铜官山铜矿矽卡岩矿物中的流体包裹体岩相学、包裹体显微测温分析及子矿物的扫描电镜／能谱分析(SEM／EDS)和激光拉曼探针分析(LRM)，发现石榴石、透辉石中的包裹体为流体包裹体，包裹体的均一温度(575～885℃)、盐度[w(NaCleq)13．4％～44．9％]均较高，流体包裹体中的子矿物有黄铜矿、闪锌矿、方解石、菱铁矿、钾石盐和石盐，以钾石盐最为普遍，表明流体高度富钾，具岩浆热液的典型特征。富钾流体也与该区广泛出露的燕山期高钾富碱岩体吻合。     

Geochemical Behaviors of REE and Other Trace Elements during the Formation of Strata-bound Skarns and Related Deposits: A Case Study of the Dongguashan Cu (Au) Deposit, Anhui Province, China

REE and other trace elements in the altered marbles, massive skarns and ores, as well as garnet and quartz were determined in order to examine the behaviors of trace elements during hydrothermal alteration. It is demonstrated that the high-field-strength (HFS) elements Zr, Hf, Th and Nb were immobile while other trace elements were mobile during the formation of skarns and related deposits. REE and ore-forming elements such as Cu and Ag in hydrothermally-altered marbles and skarns were provided primarily by hydrothermal fluids. In the direction transverse of the strata, the more deeply the marbles were altered, the higher the total REE abundance and the larger the negative Eu anomalies would be. The chondrite-normalized REE patterns of skarns are similar to those of the marbles, but the former are distinguished by much higher REE contents and more remarkable negative Eu anomalies. Those patterns were apparently not inherited from the marble protolith, but were controlled by garnets, which were determine     

羊拉地区含矿夕卡岩流体包裹体特征及其成因意义带

羊拉铜矿化集中区共有４个夕卡岩体,按成因分为喷流－沉积和接触交代夕卡岩两大类,前者呈层状,是铜的主要赋矿围岩。层状夕卡岩中包裹体以类型多、组分复杂、均一温度（１００～６２０℃,一般大于３００℃）和盐度（８．３％～５５．０％ＮａＣｌ,一般≥２０％ＮａＣｌ）高且变化范围大、密度高（一般大于１．００ｇ／ｃｍ３）、捕获压力低（１０～２５ＭＰａ）为特征;交代夕卡岩则以包裹体类型简单、组分单一、均一温度（一般小于２５０℃）和盐度中—低（９．０％～２０．０％ＮａＣｌ）、密度低（一般小于１．００ｇ／ｃｍ３）且变化范围大、捕获压力高（１５０ＭＰａ）为特征。这些包裹体特征反映了两类夕卡岩的流体来源和演化机制是不同的,其中层状夕卡岩之流体为深部源与海水源的二元混合特征;交代夕卡岩为岩浆（体）源等组分自然冷却演化趋势。     

The Discovery of Magnesioferrite from Au (Fe, Cu) Magnesian Skarn Deposits and Study of the Magnesioferrite-Magnesiomagnetite Series

Magnesioferrite, a rare metasomatic mineral, was discovered for the first time in China from the Qinlou Au (Fe, Cu) magnesian skarn deposit, Sanpu, Huaibei, Auhui Province, and the Mulonggou Fe (Mo, Cu) magnesian skarn deposit, Luonan County, Shaanxi Province. In this paper, the geological setting, mineral associations, chemical composition, some physical properties, X-ray powder diffraction data and infrared spectroscopy of magnesioferrite and magnesiomagnetite are discussed. Magnesioferrite contains 17.66%-13.48% of MgO. Its main associated minerals are clinohumite, chondrodite, serpentine,, calcite and magnesiomagnetite. The density of magnesioferrite is 4.537-4.720, reflectances in percent are: 17.8-18.1, hardness is 838-900 kg/mm2, and the cell parameter a0 = 8.371-8.379 A. A systematic study of the magnesioferrite-magnesiomagnetite-magnetite series suggests that along with the increase of magnesioferrite molecules in the mineral, the density, reflectances and cell parameters decrease corresponding     

山东海阳土堆金矿床地质特征

山东海阳县土堆金矿床位于郭城断裂带以东,赋存在荆山群野头组大理岩与燕山期闪长玢岩接触带内侧。金矿体受ＮＥ向次级构造裂隙控制,多呈脉状、似层状产出。矿石矿物成分复杂,具夕卡岩化、黄铁矿化、硅化及碳酸盐化等蚀变,成矿过程曾发生接触交代作用。该矿床具有含金夕卡岩型矿床的一般特征,在胶东地区属于一种新的金矿类型。     

岩浆夕卡岩的地质特征及其形成机理讨论──以铜陵地区为例

铜陵地区岩浆夕卡岩具有如下特征：（１）既可产于有碳酸盐岩的环境,也可赋存于远离碳酸盐岩的辉石二长闪长岩或角岩中;（２）产出形态复杂多样,可呈透镜状、脉状、小岩床、岩瘤和不规则岩枝状或角砾岩筒等等;（３）与围岩界线截然,在易交代的大理岩中也一样。作为其围岩的大理岩可见港湾状熔蚀边及重结晶褪色边,辉石二长闪长岩出现被烘烤褪色边,夕卡岩边缘部出现矿物呈等轴状三联晶嵌生淬火边;（４）夕卡岩常常与辉石二长闪长岩紧密伴生,构成了特殊的“夕卡岩－富碱侵入岩对”;（５）夕卡岩发育有海绵陨铁结构,豆状构造、流动构造和气孔构造;（６）微量元素、稀土元素的特征与相关的火成岩相似;（７）有熔融包裹体,均一温度高达１０００℃以上;（８）其矿物组成、化学成分与接触交代夕卡岩无明显差别。岩浆夕卡岩是深部中酸性硅酸盐岩浆演化过程中形成的夕卡岩浆冷凝结晶的产物。