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1.
闽西南地区燕山晚期花岗岩黑云母特征及成因意义 总被引：1，自引：0，他引：1
本文通过黑云母的电子探针方法测试,分析闽西南地区才溪岩体、四方岩体及罗卜岭岩体中黑云母的地球化学特征及其成因意义。测试结果表明,才溪二长花岗岩中的黑云母为高铁黑云母,而四方花岗闪长岩及罗卜岭花岗闪长斑岩中的黑云母为高镁黑云母,在由黑云母成分确定的物质来源图上,它们均落入壳-幔混合源区域,表明其成因类型都是壳-幔混源型花岗岩,但随着形成时代的逐渐变新,其物质组成成分中幔源组分逐渐增多。 相似文献
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《中国科学:地球科学》2016,(12)
独石岭钨(铜)多金属矿床位于苗儿山-越城岭岩体北东部,为一个大型蚀变岩型+矽卡岩型钨(铜)多金属矿床.矿区坑道内见有两种类型的花岗岩:中粒似斑状黑云母花岗岩和中细粒黑云母花岗岩,两类花岗岩在时空上与矿体关系密切,应属于独石岭钨(铜)矿成矿母岩.矿区顶部地表见有中细粒似斑状黑云母花岗岩.本文对矿区坑道内花岗岩及顶部露头花岗岩进行了锆石LA-ICP-MS U-Pb定年,结果表明,矿区坑道内中粒似斑状黑云母花岗岩的成岩年龄约为423Ma,中细粒黑云母花岗岩的成岩年龄约为421Ma,而矿区顶部露头花岗岩的成岩年代约为217Ma,表明矿区存在加里东期、印支期两期岩浆活动.对矿区坑道内两类花岗岩岩石地球化学特征研究表明,在主量元素方面:两类花岗岩均属于钙碱性、过铝质花岗岩;微量元素蛛网图表明,两类花岗岩相对富集Cs、Rb、U、REE,而亏损Sr、Ba、P、Ti;稀土元素配分曲线表明,两类花岗岩具有向右倾斜、富集轻稀土,且还具有从中粒似斑状黑云母花岗岩到中细粒黑云母花岗岩,ΣREE总体呈降低、其中轻稀土含量降低,重稀土含量略有升高,Eu亏损越来越强烈的趋势.由此表明二者属于同源、不同阶段岩浆演化的产物,与成矿关系密切,属于独石岭钨(铜)矿的成矿母岩.利用钨矿石中的白钨矿,首次对独石岭钨(铜)矿进行了Sm-Nd同位素定年分析,获得成矿年龄为(417±35)Ma,同时还利用蚀变花岗岩型和矽卡岩型矿石中的榍石进行U-Pb定年,其结果为蚀变花岗岩型矿石中的榍石年龄为425~423Ma,而矽卡岩型中榍石年龄约为218Ma.由此表明,独石岭矿区白钨矿主要形成于加里东晚期,但印支期岩浆热液也对其有一定的影响.大型独石岭钨(铜)矿成矿母岩与矿化年龄的确定,证明南岭西段越城岭地区的北端,在加里东期也曾经发生过较强烈的成矿作用,结合南端的牛塘界钨矿,这为进一步在南岭西部寻找加里东期和印支期矿集区,提供了科学依据和典型范例. 相似文献
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南岭多时代花岗岩的钨锡成矿作用 总被引：3，自引：0，他引：3
南岭成矿带以与多时代花岗岩有关的钨锡稀有金属成矿为特色,是我国19个重点成矿区带中5个重点矿产勘察地区之一,南岭花岗岩的基础研究和地质找矿实践不断取得重要进展.本文重点介绍近年来对南岭多时代花岗岩与钨锡成矿作用的主要新认识:(1)南岭地区存在加里东期、印支期和燕山期等多时代钨锡花岗岩.(2)南岭地区燕山期含锡(钨)花岗岩构成北东向分布的准铝质A型花岗岩带,延伸约350 km,暗色包体常见,为典型的磁铁矿型花岗岩.(3)燕山早期含锡花岗岩和含钨花岗岩具有不同的岩石学特征,大多含锡花岗岩以准铝质—弱过铝质(含角闪石)黑云母花岗岩为主,而含钨花岗岩则以二云母花岗岩及白云母花岗岩为主,含锡花岗岩锆石的Hf(t)集中在2~8,而含钨花岗岩中的锆石的Hf(t)集中在8~14,表明含锡花岗岩的物源中明显有地幔物质参与,而含钨花岗岩的物源则以地壳物质为主.(4)基于南岭钨、锡花岗岩的岩石学特征,研究表明榍石、磁铁矿和黑云母等常见矿物是含锡花岗岩成矿能力的有效标志,而黑钨矿等矿物可以作为含钨花岗岩的重要判别标志.本文认为,南岭复式岩体不同时代花岗岩之间的内在联系、南岭不同时代含钨锡花岗岩的成矿特征、南岭含矿长英质岩脉与岩浆演化关系、南岭花岗岩穹窿与成矿关系等应该是今后南岭花岗岩研究中需要重点关注的科学问题. 相似文献
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东溪-南关岭金矿为北淮阳东段发现的第一个原生金矿,产于磨子潭-晓天中生代火山盆地边缘,容矿围岩为安山质-英安质火山岩,矿化和蚀变受桐柏-桐城深大断裂带的次级构造带控制。该金矿发育陡倾斜的脉状矿体和缓倾斜的似层状矿体,成因类型为冰长石-绢云母型浅成低温热液金矿。火山岩盆地之下的变质基底可能起到了初始矿源层作用,桐柏-桐城断裂带及其次级构造破碎带为重要的导岩导矿构造,早白垩世强烈的岩浆活动提供了热源、动力源和部分矿源。参照国内外类似金矿的特征,认为本区成矿地质条件良好,有可能隐伏着与石英正长岩体有关的细脉浸染型矿化,晓天火山盆地具有良好的找矿前景。 相似文献
5.
广东始兴南山钨锡多金属矿床位于南岭成矿带东段,是中国地质调查局南京地质调查中心在新一轮钨多金属矿找矿工作实施中根据＂模型找矿＂找到的具有大型远景的钨锡钼铋多金属矿床。最新研究和工程钻探成果显示矿区分南北两个矿带,已圈定规模较大的钨锡多金属矿脉（体）10多条（个）,矿化类型有矽卡岩型、蚀变花岗岩型（云英岩型）、斑岩型和石英脉型。各种类型的矿体在空间上既有独立产出,又有共存一体、相伴而生,构成＂多位一体＂的复合矿床。其中以矽卡岩型钨锡铋多金属矿体、斑岩型钨钼多金属矿体和蚀变花岗岩型钨钼多金属矿体规模最大。本文通过该区地质、地球化学及主要钨锡钼铋多金属矿体特征的分析研究,指出了南山矿区的资源潜力,提出南山地区钨锡钼铋多金属矿的找矿方向。 相似文献
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7.
藏东雀儿山复式花岗岩体成因及构造背景:年代学、地球化学与锆石Lu-Hf同位素制约 总被引：1，自引：0，他引：1
雀儿山复式花岗岩体位于藏东义敦岛弧北段,主体为粗粒似斑状黑云母钾长-二长花岗岩,岩体东侧与南西侧发育小面积的细粒含斑黑云母二长花岗岩与含条纹长石斑晶花岗闪长岩.本文对雀儿山复式花岗岩体进行了主微量元素,锆石U-Pb年龄与Hf同位素研究.结果显示粗粒似斑状黑云母钾长-二长花岗岩,细粒含斑黑云母二长花岗岩高SiO2(73.5%~77.7%),高碱(全碱6.9%~8.5%),高Ga/Al比值(2.6~3.4),低Al2O3(11.8%~14.5%),低CaO(0.25%~1.5%),低MgO(0.18%~0.69%),亏损Ba,Sr和Eu,具较高形成温度等均表现出A型花岗岩的特征.两者野外接触关系以及锆石U-Pb年龄分别为(105.9±1.3)和(102.6±1.1)Ma,均表明粗粒似斑状黑云母钾长-二长花岗岩形成略早,为两期A型岩浆活动.含条纹长石斑晶花岗闪长岩则相对低SiO2、低碱、高Al2O3、高CaO和高MgO,矿物组合等均表现出I型花岗岩的特征,与早期A型花岗岩的包裹关系显示I型花岗质岩浆活动可能要早于A型花岗质岩浆活动.因此,雀儿山花岗岩体为三期岩浆事件形成的复式花岗岩体.早期A型花岗岩与晚期A型花岗岩176Hf/177Hf比值分别变化在0.282692~0.282749和0.282685~0.282765,εHf(t)值变化在-0.56~1.43和-0.87~1.90,TDM2变化在1.04~1.22和1.07~1.2 Ga,显示两者源区具有相似性.均一的Hf同位素组成,结合野外未见到岩浆混合的标志-暗色微粒包体,表明源区没有或很少的地幔物质加入,其源岩可能为分布于扬子西北缘的康定杂岩,义敦岛弧下可能具有亲扬子的元古宙结晶基底.雀儿山A型花岗岩的形成可能为班公湖-怒江特提斯洋闭合在义敦岛弧区的响应. 相似文献
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皖南新元古代花岗闪长岩沿祁门-歙县-三阳深断裂呈串珠状出露。本文在对其岩石学、地球化学细致分析的基础上,探讨了岩体的岩石成因和产出环境。皖南新元古代花岗闪长岩主要由石英、钾长石和斜长石组成,普遍含富铝矿物黑云母和堇青石,副矿物包括锆石、磷灰石、钛铁矿、独居石、磷钇矿、极少的磁铁矿等。地球化学分析数据显示,岩石总体具高硅、高钾、高铝和低钠、低镁、低钙的特征;岩石富碱（ALK=6．63％）,高K2O／Na2O比值（1．33）。里特曼指数δ为0．8～2．91,碱度率AR为1．56～3．14,属高钾钙碱性系列。岩石铝饱和指数（A／CNK-1．31）大于1．1,具强过铝质S型花岗岩的特征。岩石稀土元素呈轻稀土富集、重稀土亏损的特征,∑LREE／∑HREE比值为5．36～8．36,具较强的负铕异常（δEu=0．39～0．7）,配分模式为右倾“V”字形态;微量元素明显富集Rb、Th而亏损Ba、Nb、Ta、Sr等,为低Sr高Yb型花岗岩。地球化学特征显示其岩浆源于围岩-中元古代牛屋组浅变质千枚岩的部分熔融,反映陆-陆碰撞挤压造山环境,为晋宁运动晚期华夏板块向北俯冲与扬子板块碰撞造山的火山弧产物。 相似文献
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通过对西藏日土县材玛铁矿床的调查研究表明,南羌塘拗陷带的材玛铁矿床成矿地质条件较好.经地表槽探揭露和深部钻探工程控制,发现其矿体为似层状;矿体品位和厚度沿走向和倾向变化较小;容矿岩石主要为矽卡岩、矽卡岩化灰岩;矿石类型简单,主要为磁铁矿矿石.矿化富集与侵入于上三叠统地层的燕山晚期花岗闪长岩、二长花岗岩、花岗斑岩密切相关;矿体产出部位严格受碳酸盐岩层位及其层间破碎带的控制,属接触交代型矿床.其形成与燕山晚期岩浆活动关系密切,空间分布严格受岩浆岩和断裂的控制.花岗岩类岩体与上三叠统地层的接触带和层间破碎带是寻找铁矿的有利部位,外围地区具有寻找相同类型铁矿床的远景. 相似文献
10.
桂北牛塘界加里东期花岗岩及其矽卡岩型钨矿成矿作用研究 总被引：3，自引：0，他引：3
桂北牛塘界钨矿位于南岭西段,地处广西北部资源县和兴安县交界处,属层状矽卡岩型白钨矿床,岩株状细粒二云母花岗岩在时空上与其有密切的联系.利用LA-ICP-MS锆石U-Pb原位定年方法,获得花岗岩的侵位年龄为(421.8±2.4)Ma,与相邻的越城岭花岗岩体同属于加里东期岩浆活动产物.含钨矽卡岩中主要脉石矿物为石英、石榴子石和透辉石等.矿物组合显示,白钨矿的形成经历了两个阶段:石英-白钨矿阶段和石英-硫化物-白钨矿阶段.对矽卡岩中的白钨矿进行了Sm-Nd同位素分析,获得了钨成矿年龄为(421±24)Ma,虽然该数据误差较大,但仍清楚表明岩体与成矿作用都发生在加里东期.花岗岩中锆石的εHf(t)值为-6.5~-11.6,Hf同位素两阶段模式年龄为1.79~2.11 Ga,说明花岗岩的源区可能为中元古代的地壳物质.矽卡岩中白钨矿的εNd(t)为-13.06~-13.26,说明其成矿流体也来源于古老的地壳物质.研究表明,在南岭地区西段存在的加里东期岩浆活动为加里东期的钨成矿作用提供了物源. 相似文献
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This paper deals with the geology and geochemistry of the Gacun and Laochang large-sized marine volcanic rock-type Ag deposits in the Sanjiang (Tri-River) area of southwestern China and of the continental volcanic-subvolcanic rock-type Ag deposits in the Tianshan area of Xinjiang, and in the East area, China. It is considered that the marine volcanic rock-type Ag deposits occur mainly in the second-ordered volcano-sedimentary basins developed in island-arc and rift tectonic environments. The Ag deposits show an obvious zonation, with vein-network mineralization in the lower parts and hot water sedimentary rock-hosted stratified mineralization in the upper parts. From the Earth's surface downwards the ore-forming elements follows the order of As(Au))→Ag, Pb, Zn→Cu. The whole rock Rb-Sr isotopic isochron age of layered orebodies in the Gacun deposit is 204±14 Ma, indicating that the main stage of mineralization is Late Triassic in age. The continental volcanic-subvolcanic (porphyry) rock-type Ag deposits were formed later than the country rocks. The ores exhibit disseminated, veinlet disseminated, network and lumped structures. In addition, this study also deals with the geochemical characteristics of the continental volcanic-subvolcanic rock-type Ag deposits and the relations between Ag deposits or silver itself and fluorite, halogen-family elements and manganese. 相似文献
12.
This paper deals with the geology and geochemistry of the Gacun and Laochang large-sized marine volcanic rock-type Ag deposits in the Sanjiang (Tri-River) area of southwestern China and of the continental volcanic-subvolcanic rock-type Ag deposits in the Tianshan area of Xinjiang, and in the East area, China. It is considered that the marine volcanic rock-type Ag deposits occur mainly in the second-ordered volcano-sedimentary basins developed in island-arc and rift tectonic environments. The Ag deposits show an obvious zonation, with vein-network mineralization in the lower parts and hot water sedimentary rock-hosted stratified mineralization in the upper parts. From the Earth’s surface downwards the ore-forming elements follows the order of As(Au)) →Ag, Pb, Zn→Cu. The whole rock Rb-Sr isotopic isochron age of layered orebodies in the Gacun deposit is 204±14 Ma, indicating that the main stage of mineralization is Late Triassic in age. The continental volcanic-subvolcanic (porphyry) rock-type Ag deposits were formed later than the country rocks. The ores exhibit disseminated, veinlet disseminated, network and lumped structures. In addition, this study also deals with the geochemical characteristics of the continental volcanic-subvolcanic rock-type Ag deposits and the relations between Ag deposits or silver itself and fluorite, halogen-family elements and manganese. 相似文献
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We propose that competent layers composed of silicified rocks in the Cretaceous Ryoke low-pressure/temperature (low- P/T ) metamorphic belt in the Iwakuni–Yanai area, Southwest Japan, may be an exhumed equivalent of a seismically-reflective bright-layer in the middle crust. Silicified rocks crop out as layers or long lenticular bodies several to fifteen meters in thickness, and they are restricted to the area of greenschist facies conditions within a structural thickness of about one kilometer. The silicified rock layers exhibit a sharp contact with subjacent biotite schist but a gradational contact with overlying pelitic schist. Silicified rock is mainly composed of fine-grained quartz and minor muscovite and biotite, and some colored minerals have been variably decolorized by alteration. This implies that silicification turned the color of pelitic schists to pale gray or milky white. Quartz veins cutting schistosity at high angles were preferentially developed in the silicified rocks, while schistosity-parallel quartz veins, which underwent viscous flow, were observed in the underlying biotite schists. En echelon quartz veins and fishnet-like quartz veins are characteristic of silicified rocks. The modes of occurrence of quartz veins indicate that silicified rocks were competent relative to underlying biotite schist. The combination of contact with high-competence contrast adjacent to low-permeability silicified rocks may be a good reflector of seismic waves. If the silicified rocks were distributed in the middle crust to a considerable extent, they may result in seismic bright-layer reflections. 相似文献
14.
WenDi Chen WenLan Zhang RuCheng Wang ZhuYin Chu Rong Xiao Di Zhang XuDong Che 《中国科学:地球科学(英文版)》2016,59(11):2121-2141
The polymetallic Dushiling W-Cu deposit is a large, altered, skarn-type deposit, located in the northeastern part of the Miao'ershan-Yuechengling pluton, China. Two types of granite have been identified in the deposit: a medium-grained porphyritic biotite granite, and a medium- to fine-grained biotite granite. Both are spatially and temporally related to ore bodies, suggesting they may be the source of mineralization in the deposit. A medium- to fine-grained porphyritic biotite granite is exposed at the surface in the region of mineralization. U-Pb dating of zircons yielded magmatic ages of 423 Ma for the medium-grained porphyritic biotite granite and 421 Ma for the medium- to fine-grained porphyritic biotite granite, while a younger age(217 Ma) obtained for surface samples indicates later diagenesis. Thus, magmatism occurred during the Caledonian and Indosinian, respectively. The petrological and geochemical characteristics of the two Caledonian granites show that both are calc-alkaline and peraluminous.They are moderately enriched in Cs, Rb, U, and REE, and strongly depleted in Sr,Ba,P,and Ti; they show similar REE behavior,including negative Eu anomalies. These geochemical similarities suggest that the two granites were derived from the same source,although they were emplaced during different stages of the evolution of the magma. Furthermore, the granites are associated with mineralization, suggesting they were the source of mineralization in the Dushiling W-Cu deposit. Sm-Nd ages of scheelite from the Dushiling W-Cu deposit indicate that metallogenesis occurred at 417±35 Ma, while the two types of titanite, intergrown with scheelite, yield U-Pb ages of 423–425 Ma(in altered granite sample) and 218 Ma(in skarn sample). These ages place the main mineralization event in the late Caledonian, and later magmatic-hydrothermal activity occurred in the Indosinian. The ages obtained for the Dushiling W-Cu deposit in the western Nanling Range, northern Yuechengling, together with the occurrence and ages of the Niutangjie W deposit in southern Yuechengling, provide insight into the process of ore concentration during the Caledonian and Indosinian. 相似文献
15.
~(40)Ar/~(39)Ar and Rb-Sr isochron dating of the gold deposits on northern margin of the Jiaolai Basin,Shandong,China 总被引：7，自引：0，他引：7
The Shandong Peninsula (Jiaodong) is a very important gold producer of China. Over ten large and super-large quartz-vein type and shear zone-type gold deposits related to Yanshannian granite intrusions have been exploited in the northern part of the Jiaod… 相似文献
16.
40Ar/39Ar and Rb-Sr isochron dating of the gold deposits on northern margin of the Jiaolai Basin, Shandong, China 总被引：1，自引：0，他引：1
Lianchang Zhang Yuanchao Shen Tiebing Liu Qingdong Zeng Guangming Li Houmin Li 《中国科学D辑(英文版)》2003,46(7):708-718
The Pengjiakuang, Dazhuangzi and Fayunkuang gold deposits, located on the northern margin of the Mesozoic Jiaolai Basin, east
of Shandong Province, are controlled by a low-angle normal fault. Gold ores are typically brecciated, veinlet and disseminated.
The Ar-Ar and Rb-Sr isochron dating methods were adopted to date ores and lamprophyre dike. The results indicate that the
age of the Pengjiakuang gold deposit is 117.33–118.42 Ma, that of the Dazhuangzi gold deposit is 117.39 Ma, and that of the
Fayunkuang gold deposit is (128.49±7.2) Ma. The consistency in metallogenic age between the gold deposits on the margin of
the Jiaolai Basin and the gold deposits (115–126 Ma) of the northern uplift area suggests that both were formed in the same
metallogenic period. That is to say, the large-scale metallogeny of the Jiaodong region took place in late-Yanshannian ((120±10)
Ma). 相似文献
17.
广东省揭西金坑矿区目前已初步查明的（333＋334）级矿石量为2245464.8吨,其中金属量Cu：17596.7吨、Sn：5945.3吨、Pb：31536.9吨、Zn：58095.2吨。矿区主要矿体为脉状,均受滑动破碎构造带控制,总体上可分为两种类型：一类分布于灰白色花岗闪长斑岩中,在空间分布上受滑动破碎构造带控制,矿体顶底板为片理化带,蚀变强,呈脉状、透镜状产于花岗闪长斑岩体内的片理化带所产生的滑动破碎带中。另一类则产于石英片岩、粉砂岩、炭质泥岩层间滑动破碎构造带中,主要由多个连续的或间断的扁豆状、透镜体状的矿脉组成。矿体赋存严格受岩层控制,矿脉与围岩界线清楚。本文旨在通过对矿体特征、成矿机理的深入分析,为矿区为进一步扩大资源量提供理论上的启示。 相似文献
18.
西藏班戈日阿铜多金属矿床位于班戈-腾冲多金属成矿带,是近年来新发现的矽卡岩型铜多金属矿床,已探明资源量达中型规模。最新研究和找矿成果显示矿带呈北西向展布,受燕山晚期白垩纪花岗岩类岩体侵入作用控制,矿体分布于岩体与下白垩统灰岩地层接触带及附近部位。在空间上,矿床主要分为三个矿段：主矿体分布在矿区中西部,目前在西矿段已圈定5个（条）铜矿体,矿体呈似层状、透镜状,其中最大的Cu13号矿体长221 m,平均厚9 m,沿倾向已控制延深100 m以上,铜品位：0.45%~2.01%,平均0.9%。主要金属矿物为黄铜矿、磁铁矿。中矿段已经圈定3条矿体,成矿元素除铜外,铅、锌、银含量也较高,为铜多金属矿体。矿体呈似层状、透镜状。其中以Cu-23号矿体最大,长达300 m,矿体最宽处达110 m。矿体平均品位Cu1.48%,Pb 1.25%,Zn 2.52%,A g 32.52×1-0 6。本文在矿区地质特征研究的基础上,通过对1：5万水系沉积物测量成果分析,对比中、西矿段成矿条件,对矿区东段进行了预测评价,指出该矿区具有较好的铜多金属找矿前景。同时建议对已圈定的1：5万水系沉积物异常开展1：1万土壤地球化学测量工作,进而圈定该区铜多金属矿带或矿（化）体,为矿区深入勘查工作提供依据。 相似文献