湘南粤北铅锌矿床闪锌矿的标型特征及指示意义     

徐接标  张术根  左亚飞  冯雨周  卢敏晨 《岩石矿物学杂志》2016,35(2):283-296

湘南粤北位于南岭成矿带中段,是我国最重要的铅锌矿集区之一。本文选取湘南粤北地区MVT和岩浆热液型两类铅锌矿床的闪锌矿样品,对闪锌矿的形态、结构、化学成分、硫同位素组成、流体包裹体成分等进行系统研究,分析其成矿温度、硫的来源和成矿流体特征,为揭示成矿作用提供可靠依据。研究结果表明:MVT铅锌矿床成矿作用发生在中低温、氧化-弱还原、较低压力环境,硫主要来源于容矿地层,成矿流体主要来自于热卤水和沉积物变质脱水;岩浆热液型铅锌矿床成矿作用发生在中高温、弱还原、较高压力条件下,硫源主要以岩浆硫为主,成矿流体早期以岩浆热液为主,晚期为混合流体。结合矿体与岩体的形成时间、空间分布、大地构造背景,认为岩浆热液型铅锌矿床由燕山早期(180~150 Ma)古太平洋向大陆俯冲、岩石圈加厚,爆发大规模花岗质岩浆岩侵位,导致铅锌成矿;MVT铅锌矿床由燕山晚期(130~90 Ma)欧亚大陆岩石圈伸展减薄产生的岩浆热液叠加改造泥盆系的原始矿源层形成。  相似文献   

He-Ar-S-Pb Isotopic Compositions of Pyrite: Constraints on the Source of Ore-forming Materials of the Chengchao Skarn Iron Deposit, SE Hubei Province, Eastern China     

LI Wei  XIE Guiqing  ZHU Qiaoqiao 《《地质学报》英文版》2016,90(5):1780-1794

The Chengchao iron deposit,the largest high-grade skarn iron deposit in southeastern Hubei Province,contains considerable amounts of magnetite and by-product anhydrite.To obtain better understanding of the ore-formation process,this study carried out He-Ar-S-Pb multi-isotopic analyses on the pyrites formed during two stages of mineralization.The results indicate that the δ~(34)S values(ranging from 14.0‰ to 17.6‰) of pyrites formed from the two stages have no obvious differences,suggesting that they were not derived from a single magmatic sulfur source.The δ~(34)S values of anhydrite mostly range from 21.9‰ to 28.4‰,similar to that of the Middle Triassic sedimentary anhydrite in the Middle-Lower Yangtze River metallogenic belt(MLYRB).The Pb isotopic compositions of the pyrites of both stages are homogeneous,with values of ~(208)Pb/~(204)Pb,~(207)Pb/~(204)Pb,and~(206)Pb/~(204)Pb being 38.006-38.257,15.523-15.556,and 17.806-18.052,respectively,indicating a mixed crust-mantle source.The He-Ar results exhibit different compositions of the two stages:the ~3He/~4He(R/Ra) and ~(40)Ar/~(36)Ar values for the early-stage pyrite are 0.46-0.63 and 311-322,respectively,whereas the values for late-stage pyrite are 0.23-0.34 and 305-361,respectively.Both stages of pyrites indicate the multiple sources of the ore-forming fluids,with decreasing amount of magmatic water and increasing amount of modified meteoric water(MASW) during fluid evolution.The Triassic evaporites played an important role in the mineralization process.  相似文献   

西藏铁格隆南铜(金银)矿床地质特征及勘查模型——西藏首例千万吨级斑岩-浅成低温热液型矿床   总被引：16，自引：0，他引：16  

唐菊兴  宋扬  王勤  林彬  杨超  郭娜  方向  杨欢欢  王艺云  高轲  丁帅  张志  段吉琳  陈红旗  粟登逵  冯军  刘治博  韦少港  贺文  宋俊龙  李彦波  卫鲁杰 《地球学报》2016,37(6):663-690

铁格隆南矿床(荣那矿段)位于多龙矿集区多不杂斑岩型铜(金)矿的北东中部,铜(金)矿体的主要赋矿围岩为早白垩世中酸性斑岩及早中侏罗统色哇组(J1-2s)复理石或类复理石建造;下白垩统美日切错组(K1m)陆相中基性火山岩建造(110 Ma)覆盖在斑岩-浅成低温热液成矿系统之上,是该矿床得以良好保存的重要原因。通过详细的地质填图、地质编录、岩石地球化学、镜下鉴定、电子探针分析、流体包裹体分析、同位素年代学、岩石地球化学测量、音频大地电磁测深和综合研究,确定了矿体形态整体上为一个似筒状体,铜(金、银)矿体总体呈北东向,控制矿体北东延长约2 000 m,南东—北西向约1 200 m,Cu平均品位大于0.5%,伴生Au品位0.08 g/t,伴生银品位2 g/t左右,单个矿床铜资源量约1 100万吨,远景资源量超过1 500万吨。矿石以典型的细脉浸染状为主,从浅部至深部,金属矿物由铜蓝、蓝辉铜矿、斯硫铜矿、雅硫铜矿、久辉铜矿、斜方蓝辉铜矿及黄铜矿、斑铜矿(微量辉钼矿),主要非金属矿物有明矾石、地开石、高岭石、水铝石、绢云母、石英、硬石膏等组成(图2-17),矿物和蚀变组合显示高硫型浅成低温热液矿体叠加于斑岩型矿体。成矿岩体为120 Ma侵位的花岗闪长斑岩,辉钼矿Re-Os同位素年龄显示斑岩成矿形成于119 Ma左右,明矾石Ar-Ar同位素测年结果为116 Ma左右,表明浅成低温热液型矿化略晚于斑岩型矿化。由于羌塘地体南缘的不断隆升,导致浅成低温热液矿化持续向深部迁移,形成巨厚典型的浅成低温热液矿物组合。流体包裹体研究表明,流体包裹体均一温度显示存在2套明显不同温度的流体,即形成斑岩及其围岩钾硅化与绢英岩化带矿化的中高温流体以及高级泥化带中的中低温流体,高温、高盐度的流体代表了斑岩系统的流体特征,而中低温、低盐度的流体代表了高硫化型浅成低温热液系统的流体特征。铁格隆南矿区的岩体侵位较浅,浅部岩体已经在ZK1604与美日切错组呈角度不整合接触,表明在美日切错组火山岩喷发覆盖于矿体上之前,含矿岩体已经出露地表,根据其估算形成深度(约1.2 km),可以判断在矿床形成之后地壳已抬升了一定高度,斑岩-浅成低温热液系统上部的矿体和独立金矿体可能已被剥蚀。岩石微量元素和稀土元素特征表明,均为高钾钙碱性,富集大离子亲石元素,亏损高场强元素,具弧岩浆地球化学特征;在Y-Th/Ta和Ta/Yb-Th/Yb图解中多龙地区主要侵入岩均位于活动大陆边缘,在Th-Co-Zr/10和Th-Sc-Zr/10微量元素构造图解中,大部分样品落在陆缘弧区域。区域上构造岩浆活动也表明多龙地区岩浆岩形成与班公湖—怒江特提斯洋早白垩世北向俯冲至南羌塘地体之下密切相关,类似于南美安第斯成矿带洋陆俯冲背景下的陆缘弧环境。锆石铪同位素落在球粒陨石与亏损地幔之间,地壳模式年龄相对年轻与多龙地区主要侵入岩一致,表明岩浆主要来源亏损地幔,同时也有部分新生地壳物质的加入,岩浆表现出角闪石源区作为主要源区熔融矿物的特征,表明班公湖-怒江特提斯洋壳俯冲至50~70 km下发生相变,从而导致类似角闪石等矿物脱水引发的楔形地幔部分熔融。短波红外光谱填图和岩石地球化学剖面测量显示在尕尔勤、地堡那木岗还有寻找铁格隆南(荣那矿段)式矿床的潜力,区域找矿潜力极大,多龙矿集区铜资源量可以达到2 500万吨以上。  相似文献   

东天山三宫铜镍矿化岩体年代学、岩石地球化学特征及对Cu-Ni找矿的启示     

王亚磊  张照伟  尹希文  李侃  尤敏鑫  王博林 《地球学报》2016,37(6):699-710

三宫岩体是近几年新发现的铜镍矿化镁铁-超镁铁岩体,位于哈尔里克山东段。岩石类型主要为辉长岩、斜长辉石岩和含长橄榄辉石岩,局部有零星铜镍矿化。锆石U-Pb谐和年龄为(281.7±2.6)Ma,表明岩体形成于早二叠世。样品MgO与FeO~T呈正相关关系,与CaO、SiO_2和Al_2O_3之间呈负相关关系,岩体主量元素成分主要受橄榄石和单斜辉石含量的控制;样品明显富集轻稀土元素(La/Yb)N=5.02~7.04,重稀土元素之间具有明显的分馏(Gd/Yb)N=2.36~2.87,δEu为0.98~1.09多具弱的正铕异常,富集大离子亲石元素(Cs、Sr、Ba),相对亏损高场强元素,具明显的Nb、Ta、Ti负异常。Sr-Nd同位素模拟计算表明母岩浆上升过程中遭受了约10%的下地壳物质混染。岩浆源区遭受了明显的熔体交代作用,部分熔融主要发生在石榴子石稳定域。综合区域构造演化历史认为三宫岩体形成于后碰撞伸展环境,该岩体的发现初步表明哈尔里克地区也具有寻找早二叠世铜镍矿的潜力。  相似文献   

贵州水银洞金矿矿层矿化分析与深部预测          下载免费PDF全文

刘帅  彭进  刘建中  王泽鹏  杨成富 《高校地质学报》2016,22(1):66

水银洞金矿为滇黔桂"金三角"最重要的金矿床,是典型的卡林型层控金矿床。运用绘制等高线图和含矿层矿化分布图的方法,对水银洞矿床0~427勘探线的钻孔数据分析,并用surfer软件绘制矿层的顶底板和地层矿化趋势的模拟图,重点分析了含矿地层的构造形态和矿化规律,结果显示:界面等高线反应背斜的形态,水银洞矿区背斜的高点和背斜倾伏端是金矿的主要赋存位置;Sbt(构造蚀变体)与上部龙潭组矿化值有负相关效应;水银洞矿化整体具有不均匀性,Sbt向东南延伸且在东西向具有弱—强—弱的富集规律。Sbt矿化强度在东西向具有弱—强—弱的规律,而龙潭组地层中的矿化与Sbt呈现一定负相关效应,在背斜倾伏端龙潭组矿化度开始增强,预示深部地层可能还会有大规模的工业矿体存在。  相似文献   

The Cretaceous Ofuku Pluton and Its Relation to Mineralization in the Western Akiyoshi Plateau,Yamaguchi Prefecture,Japan          下载免费PDF全文

Yuka Sasaki  Teruyoshi Imaoka  Mariko Nagashima  Kazuo Nakashima  Takafumi Sonehara  Koshi Yagi  Tetsumaru Itaya 《Resource Geology》2016,66(2):85-113

The relationship between the magmatism of the Cretaceous Ofuku pluton and mineralization in and around the Akiyoshi Plateau, Yamaguchi Prefecture, Japan was investigated using a combination of field observation, petrographic and geochemical analyses, K–Ar geochronology, and fluid inclusion data. The Ofuku pluton has a surface area of 1.5 × 1.0 km, and was intruded into the Paleozoic accretionary complexes of the Akiyoshi Limestone, Ota Group and Tsunemori Formation in the western part of the Akiyoshi Plateau. The pluton belongs to the ilmenite‐series and is zoned, consisting mainly of early tonalite and granodiorite that share a gradational contact, and later granite and aplite that intruded the tonalite and granodiorite. Harker diagrams show that the Ofuku pluton has intermediate to silicic compositions ranging from 60.4 to 77.9 wt.% SiO₂, but a compositional gap exists between 70.5 to 73.4 wt.% SiO₂ (anhydrous basis). Modal and chemical variations indicate that the assumed parental magma is tonalitic. Quantitative models of fractional crystallization based on mass balance calculations and the Rayleigh fractionation model using major and trace element data for all crystalline phases indicate that magmatic fractionation was controlled mainly by crystal fractionation of plagioclase, hornblende, clinopyroxene and orthopyroxene at the early stage, and quartz, plagioclase, biotite, hornblende, apatite, ilmenite and zircon at the later stage. The residual melt extracted from the granodiorite mush was subsequently intruded into the northern and western parts of the Ofuku pluton as melt lens to form the granite and aplite. The age of the pluton was estimated at 99–97 Ma and 101–98 Ma based on K–Ar dating of hornblende and biotite, respectively. Both ages are consistent within analytical error, indicating that the Ofuku pluton and the associated Yamato mine belong to the Tungsten Province of the San‐yo Belt, which is genetically related to the ilmenite‐series granitoids of the Kanmon to Shunan stages. The aplite contains Cl‐rich apatite and REE‐rich monazite‐(Ce), allanite‐(Ce), xenotime and bastnäsite‐(Ce), indicating that the residual melt was rich in halogens and REEs. The tonalite–granodiorite of the Ofuku pluton contains many three‐phase fluid inclusions, along with daughter minerals such as NaCl and KCl, and vapor/liquid (V/L) volume ratios range from 0.2 to 0.9, suggesting that the fluid was boiling. In contrast, the granite and aplite contain low salinity two‐phase inclusions with low V/L ratios. The granodiorite occupies a large part of the pluton, and the inclusions with various V/L ratios with chloride daughter minerals suggest the boiling fluids might be related to the mineralization. This fluid could have carried base metals such as Cu and Zn, forming Cu ore deposits in and around the Ofuku pluton. The occurrence and composition of fluid inclusions in the igneous rocks from the Akiyoshi Plateau are directly linked to Cu mineralization in the area, demonstrating that fluid inclusions are useful indicators of mineralization.  相似文献   

A discussion on vertical profiles of dissolved Cu,Cd and Ni in the northwestern Pacific, south of Japan     

Wang Zhengfang  Ohyama Junichi 《海洋学报(英文版)》1993,12(4):597-603

Some of the results about vertical profile of heavy metals of seawater to the south of Japan in Oct. 1990 are presented and discussed in relation to the concentration of dissolved Cu, Cd and Ni to biogeochemical environments. It points out that the distribution of dissolved Cu is higher in surface water than that in/upper 500 m layer, and maxima value attains the 8. 2 n mol/dm3 in depth of 4 000 m. The concentrations of dissolved Ni ranges from 3. 4 n mol/dm3 in surface seawater to 8. 5 n mol/dm3 in the deep to the south of Japan. The highest values are observed in the colder waters. This paper shows also that the vertical profile of dissolved Cd is perfect nutrient-type distribution. And dissolved Cd and Phosphate are linearly correlated by the regression equation. The ·Cd : ·N : ·P atomic ratio is 3. 5 × 10-4 : 14 : 1.  相似文献   

铁锰结核结壳生长过程的一种理论假设   总被引：4，自引：0，他引：4  

姚德  张丽洁  许东禹  梁宏锋 《海洋地质与第四纪地质》1994,(2)

铁锰结核成矿物质的直接来源是大洋底层水和沉积物孔隙水，结壳只有底层水，因此，底层水和孔隙水的物理化学特征就成为理解铁锰结核（壳）成矿作用特征与过程的关键。铁锰结核（壳）内部构造的两个明显特征是：①韵律性的环状纹层构造，和②树枝状构造，这两种构造是典型的远离平衡的非线性地质作用的产物。正常情况下，海底水—沉积物界面系统的底层水、孔隙水中Ｍｎ、Ｆｅ是不饱和的。因此，铁锰结核（壳）不可能在平衡状态下连续生长。本文提出铁锰结核（壳）生长的自反馈“振荡式”模型。  相似文献   

The nature and origin of light hydrocarbon gases associated with mineralization in the Northern Pennines     

J. Ferguson 《Marine and Petroleum Geology》1988,5(4)

Earlier studies have shown the occurrence of anomalous amounts of methane in rocks associated with lead/zinc mineralization in a number of deposits in the British Isles and Europe. This has led to speculation that the gas may have originated either as a consequence of reactions involved in the mineralization process or as a result of maturation of the organic matter in the sediment or from a deep source. New data are presented showing the distribution of light hydrocarbon gases from fluid inclusions in minerals from the North and South Pennine Orefields which differ from those observed in the host rocks. Possible sources for the gases in the host rocks and the minerals are examined. Based on the close correlation between the distribution of the gases in the carbonate rocks of Northern England and the conodont colour alteration index map for the area, it is suggested that the anomalous amounts of methane gas in the Northern Pennine host rocks are the result of maturation prior to mineralization. The distribution of gases in the fluid inclusions in the minerals serves as a distinguishing feature, and two assemblages are recognized from the South Pennine Orefield, both of which are distinct from that of the Northern Pennines. It is concluded that these gases, trapped at the time of mineralization, originate as a consequence of reactions which occurred during mineral deposition.  相似文献   

云开地区燕山期岩浆活动与金银矿化关系   总被引：1，自引：0，他引：1  

甘志邦 《矿产与地质》1992,6(5):380-386

通过对广西云开地区岩浆活动与金银矿化关系的研究表明,金银矿主要是燕山期岩浆作用形成的;矿化岩体与金银矿化在空间位置上存在“东向性”和“定距性”规律;岩浆岩岩石化学成分、岩浆分异程度、成因类型的不同,导致了金银成矿的显著差异;燕山期岩浆活动对金银成矿,既提供了成矿热液,也提供了主要的物质来源。  相似文献