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新疆的印支运动与成矿 总被引：25，自引：0，他引：25
随着高精度同位素年代学研究的深入,一些长期被认为属于海西期甚至加里东期的地质体被证明形成于印支期。在新疆及其周边的广大地区,印支运动主要表现在下述3个方面:①以中酸性小岩体-伟晶岩-细晶岩-辉绿岩-煌斑岩脉为主的岩浆侵入体,个别地区存在印支期的辉长岩-闪长岩体,这些侵入体多数显示金-铜-稀有金属矿化的特征,部分岩体本身就是矿体或者其中含矿;②很多韧性剪切带在印支期活动,大多数剪切带的最后一次韧性变形发生在印支期;③天山地区绝大多数与韧性剪切带有关的金矿均形成于印支期,印支期是中亚地区最重要的成矿时代之一。印支运动在天山和阿尔泰山有不同的表现形式,其地球动力学背景也完全不同。 相似文献
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卡而却卡-虎头崖矿区地处东昆仑西段祁漫塔格山中部,大地构造上位于祁漫塔格结合带与北昆仑岩浆弧一带,属于祁漫塔格-都兰华力西期成矿带,形成了规模较大的铜、铁、铅、锌、钼、锡、锑等矿床.该区构造上处于昆北断裂与昆中断裂之间,且岩浆活动极为强烈,区内发育花岗岩、闪长岩类为主的中酸性侵入岩,以华力西期-印支期岩体为主,其次为加里东期和燕山期岩体产出.实地调研及前人大量资料表明,在卡而却卡-虎头崖一带,以中晚印支期的岩浆活动最为发育,其侵入体与成矿的关系也最为密切(何书跃等,2008;王秉璋,2004;张晓飞,2011). 相似文献
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苏鲁超高压带北段夏河城岩体的形成时代及其意义 总被引：2，自引：0，他引：2
位于苏鲁超高压变质带北段的夏河城岩体由角闪辉长岩、闪长岩和石英闪长岩组成,其中的闪长岩锆石U-Pb同位素年龄为195±17Ma。该岩体侵入于超高压变质岩中,其化学成分具I型花岗岩特点(多数样品Na2O>3%;所有样品A/NKC<1.1,均含标准矿物Di,未出现标准矿物C)。苏鲁超高压变质带中,存在3类不同成因的印支期侵入岩,其同位素年龄范围在195~227Ma,与超高压变质岩退变质阶段的年龄(202~229Ma)一致,指示超高压变质作用发生在印支期岩体形成之前。这些印支期侵入岩具有不同的岩石化学特征,指示它们的岩浆成因及来源可能有比较大的差别。在此基础上,对这些侵入岩形成时的构造背景,进行了初步讨论。 相似文献
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安徽铜陵矿集区中生代侵入岩体年代学研究及其成矿指示意义 总被引：1，自引：0，他引：1
基于前人在铜陵矿集区获得的大量高精度同位素定年数据,本文补充测定了研究程度相对较低的棋子坑、瑶山、荷花塘等11个小型侵入体的LA-ICP-MS锆石U-Pb年龄,年龄分布在147～131 Ma之间。通过对区内成岩-成矿时代进行系统分析,提出了该区为一燕山期陆内"瞬时大规模成矿作用"形成的大型矿集区。区内燕山期成矿岩体主要包括花岗闪长岩类、石英(二长)闪长岩类和辉石(二长)闪长岩类等3类中酸性侵入岩,其成岩时代主要集中在152～130Ma之间,其中,花岗闪长岩集中在148～137 Ma、石英(二长)闪长岩在152～130 Ma、辉石(二长)闪长岩在150～134 Ma,区内主要矿床中获得的辉钼矿Re-Os成矿年龄分布在141～137Ma,成岩与成矿时代相差约10Ma以内,且成矿年龄具有自东向西逐渐变新的特征,区内相邻矿田成矿时代相差2Ma左右。铜陵矿集区在141～137 Ma的短时限内三次幕式大规模成矿作用为全球陆内岩浆成矿作用中所罕见。 相似文献
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中国内生稀有稀土矿床的时空分布 总被引：11，自引：5，他引：11
内生稀有稀土矿床在我国广泛分布，矿床的形成时代从太古宙到喜马拉雅期。矿床类型主要有碱性岩型、花岗岩型及花岗伟晶岩型三大类型。碱性岩型矿床的形成时代从元古宙到喜马拉雅期，主要集中在中元古代及华力西－印支期。这类矿床多分布在地台稳定区的边缘，常沿深断裂或裂谷带延展方向呈群分布。花岗岩型矿床绝大多数形成于燕山期，主要见于南岭及其邻区。成矿花岗岩常是花岗岩复式岩体的晚期侵入体，沿大岩体周边或隐伏岩体上方作定向分布。花岗伟晶岩型矿床主要形成于华力西－印支期，大多数分布在地槽褶皱带内。褶皱带内的复背斜及更次一级背斜的轴部及倾没端常是矿化伟晶岩的赋存场所。以攀西裂谷带内的牦牛坪、茨达等碱性岩型矿床，赣南加里东褶皱带内的西华山、荡坪等花岗岩型矿床，闽西北加里东褶皱带内的溪源头、西坑等花岗伟晶岩型矿床为例具体地描述了三类矿床在空间上的定向分布。西部地区是找寻大型内生稀有稀土矿床极有潜力的地区。 相似文献
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湖南紫云山岩体的地质地球化学特征及其成因意义 总被引：6，自引：0，他引：6
紫云山岩体由花岗闪长岩和黑云母花岗岩两种岩石类型组成,前者为岩体的主体,呈环状分布于岩体的周边,发育同时代的暗色微粒包体;后者为补充侵入体位于岩体的中央部位,两者呈明显的侵入接触关系,高精度LA-ICP-MS锆石U-Pb年龄分别为222.5±1Ma和222.3±1.8Ma,都为印支晚期的产物。两种岩石类型的SiO2含量存在明显间断,A/CNK变化范围分别为0.99~1.05和1.08~1.15,花岗闪长岩为准铝质-弱过铝质I型花岗岩,黑云母花岗岩为弱过铝-强过铝质S型花岗岩。两类岩石都具有高的Rb、Cs含量和Rb/Sr比值,低的Sr、Ba、Eu含量,强-中等负铕异常,以及高的(87Sr/86Sr)i值和低的εNd(t)值,显示了前寒武纪变质基底起源的花岗岩的地球化学特征。两种岩石类型形成的温压条件和成岩深度有明显差别,暗示两者的源区不同。紫云山岩体两类岩石都是在印支陆块与华南陆块碰撞挤压-松驰构造环境下形成,岩浆底侵作用形成了少量有幔源组分加入的花岗闪长岩,其后上地壳泥砂质沉积物部分熔融形成了黑云母花岗岩。华南印支期主要花岗岩体的空间分布和高精度年龄数据显示,在华南内陆带和武夷-云开山脉带,由南而北,岩体形成时代逐渐变新,是印支陆块与华南陆块碰撞拼合所引起的挤压应力由南向北传递的结果。 相似文献
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《地质通报》2017,(Z1)
塔山花岗岩体位于湘南阳明山-塔山东西向构造-岩浆带东端,为呈近东西向延伸的岩基,出露面积约200km~2。岩体侵入于古生代地层中,接触面倾向围岩,倾角30°~50°,由四侵入次岩体组成,之间多为脉动接触关系,主要岩性为黑云母二长花岗岩。第二侵入次岩体SHRIMP锆石U-Pb年龄为218±3Ma,第三侵入次岩体SHRIMP锆石U-Pb年龄为215±3Ma。由此表明,塔山花岗岩形成于晚三叠世,相邻单元之间的时间间隔为3~5Ma。阳明山-塔山东西向构造-岩浆带主要形成于印支期。区内钨、锡、铜、铅、锌等多金属矿床丰富,找矿潜力较大,亦表明南岭地区不仅存在燕山期花岗岩成矿,印支期花岗岩也可成矿。 相似文献
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湖南省花岗岩主要形成于加里东期、印支期和燕山期,分为"I"型和"S"型两个成因类型。其中"I"型花岗岩主要为角闪(或含角闪)石英闪长岩-花岗闪长岩-二长花岗岩,Mf值(铁镁比值)多小于0.78;"S"型花岗岩主要为黑云母(或二云母)二长花岗岩-钾长花岗岩,Mf值多大于0.78."I"型花岗岩与金矿的关系更为密切,于该类岩体内或其周围形成岩浆热液型或混合热液型多金属共生金及钨锑-金矿床。根据"I"型花岗岩与金矿关系的不同特点,将其划分为自源型金成矿"I"型花岗岩带和它源型金成矿"I"型花岗岩带。"S"型花岗岩与金矿的关系仅表现为部分岩体周围发育一定程度的金矿化。 相似文献
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华北克拉通北缘及邻区印支期岩浆活动与钼和金成矿作用 总被引：4，自引：0，他引：4
对华北克拉通北缘及邻区19处钼矿床和5处金矿床的产出环境、形成时代和成矿机理及其与印支期侵入岩的关系进行了讨论。尽管各个矿床所处的地理位置不同,但是它们大都在前寒武纪或早古生代地层中产出,并且与印支期侵入岩具有密切的时空分布关系。印支期钼矿床的形成作用可以从早三叠世一直持续到晚三叠世,大规模成矿作用高峰期为230~220 Ma。相比之下,金矿床的形成时间明显早于钼矿床,同位素年龄数据集中分布在245~239 Ma。研究结果表明,自早三叠世开始,华北克拉通北缘及邻区曾发生过多期大规模伸展构造作用,并且形成若干条近东西向展布的裂陷带。张裂构造作用所诱发的富碱性岩浆作用及相关流体活动为钼或金矿床的形成提供了动力和物质来源,因此,印支期侵入岩发育区是寻找隐伏钼或金矿床的有利地区。 相似文献
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The Hadamengou gold deposit is located in the western segment of the northern margin of the North China Craton (NCC). It is hosted by Archean metamorphic rocks of the Wulashan Group. The main ore types include gold-bearing quartz vein type, gold-bearing quartz-potassic feldspar vein type, and gold-bearing altered rock type. Gold mineralization is closely related to K-feldspathization. Hydrogen and oxygen isotope data indicate that ore-forming fluids were dominated by magmatic water mixed with minor meteoric water. Sulfur and lead isotope data indicate that metallogenic materials were mainly supplied by the magmatic and Archean Wulashan Group. The gold mineralization was mainly formed during the Early Indosinian tectonic movement, which drove ore-forming fluids to the favorable depositional environment. The northern margin of the NCC is a prospective area for gold exploration. Gold deposits hosted by or related to alkaline intrusions have become one of the most important mineral exploration targets in northern China. 相似文献
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黄铁矿载金的原因和特征 总被引：21，自引：0，他引：21
对102个金矿床载金矿物的统计表明,黄铁矿是最普遍最重要的载金矿物。造成黄铁矿成为主要载金矿物的原因,有三个矿物学方面的因素,即结构因素、成核因素和电化学因素。结构因素表现在黄铁矿晶体结构中存在对硫 ［S2］2－,对硫 形成过程中对金离子具还原效应。成核因素表现在自然金成核常选择原子排布与之最接近的黄铁矿表面为衬底,以降低成核能。电化学因素表现在黄铁矿的热电性导致金离子在其表面发生电化学反应而沉淀结晶。对黄铁矿载金能力的分析表明,细粒、它形、裂隙发育程度高、As和Sb含量高以及P型的黄铁矿载金能力高,自形黄铁矿中的{210}、S面{100}及其聚形晶的载金能力高。 相似文献
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Gold Deposits in Beishan Mountain, Northwestern China 总被引：2，自引：0，他引：2
Abstract. The Beishan Mountain spans three provinces ‐ Gansu, Xinjiang and Inner Mongolia, having an area of 120,000 km2 Tectonically, it transverses three different tectonic units, i.e. Siberia, Kazakhstan and Tarim plates, and is composed of nine ter‐rains with widely exposed Precambrian and Paleozoic strata, complex structures, intensive magmatic activities and widespread ore deposits. It is not only a main part of Tianshan‐Yinshan‐Great Hinggan metallogenic belt in China, but also a key to under‐stand the evolution of central‐Asian orogenic system. At present, more than 100 gold deposits and prospects have been discovered, explored and mined, among which Nanjinshan, Mazhuangshan, Liushashan, Jinwozi, Zhaobishan and Xiaoxigong are the most important ones. Based on the host rocks and the geological features, all these gold occurrences can be subdivided into three groups (or types): (1) hosted by Carboniferous or Permian volcanic or subvolcanic rocks; (2) hosted by or related to plutonic intrusions; and (3) hosted by Precambrian metamorphic rocks. The first group includes the Mazhuangshan gold deposit, which occurs in Hercynian quartz por‐phyry and rhyolite porphyry as gold‐bearing quartz veins. The second group is composed of the Liushashan, Nanjinshan Zhaobishan and Jinwozi gold deposits. Gold mineralization at these four deposits occurs within Hercynian granitoids intrusion: or late Paleozoic sedimentary rocks as quartz veins, veinlets and altered rocks. The Xiaoxigong gold deposit belongs to the third group, and is hosted by Precambrian schist, amphibolite and migmatite as quartz veins and altered rocks. Isotopic age dating data, geological and geochemical evidence suggest that most of the groups 1 and 2 gold deposits were generated during the emplacement of the Hercynian or partly Indosinian intrusions. These intrusions may provide both heat and metals for groups 1 and 2 deposits. In contrast, although the formation is closely related to the Hercynian magma‐tism, the ore‐forming materials of the group 3 deposits may not only come from the intrusions, but also from the Precambrian metamorphic rocks. 相似文献
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Abstract. Intrusion‐related gold deposits are widely distributed within the North China craton or along its marginal fold belts. Presently, about 200 individual intrusion‐related gold deposits (prospects) have been discovered, among which Yuerya, Anjia‐yingzi, Linglong, Jiaojia, Chenjiazhangzi, Qiyugou, Jinjiazhuang, Dongping, Hougou, Huangtuliang, Guilaizhuang, Wulashan and Donghuofang are the most important ones. In general, the intrusion‐related gold deposits can be classified into three major groups according to their host rocks: (1) hosted by or related to felsic intrusions, including (la) calc‐alkaline granitoid intrusions and (lb) cryptoexplosion breccia pipes; (2) related to ultramafic intrusions, and (3) hosted by or related to alkaline intrusions. The first group contains the Yuerya, Anjiayingzi, Linglong, Jiaojia, Chenjiazhangzi and Qiyugou gold deposits. Gold mineralization at these deposits occurs within Mesozoic Yanshanian calc‐alkaline granitoid intrusions or cryptoexplosion breccia pipes as gold‐bearing quartz veins and replacement bodies. Pyrite, galena, sphalerite, chalcopyrite, native gold and electrum are major metallic minerals. The Jinjiazhuang deposit belongs to the second group, and occurs within Hercynian diopsidite and peridotite as quartz veins and replacement bodies. Pyrite, marcasite, arsenopyrite, native gold and electrum are identified. The third group includes the Dongping, Hougou, Huangtuliang, Guilaizhuang, Wulashan and Donghuofang deposits. Gold mineralization at these deposits occurs predominantly within the Hercynian alkaline intrusive complexes as K‐feldspar‐quartz veins and replacement bodies. Major metal minerals are pyrite, galena, chalcopyrite, tellurides, native gold and electrum. All these pyrite separates from Hercynian and Yanshanian intrusions or cryptoexplosion pipes associated with the gold deposits show a broad range in δ34S value, which is overall higher than those Precambrian rocks and their hosted gold deposits. For the alkaline intrusion‐related gold deposits, the δ34S values of the sulfides (pyrite, galena and chalcopyrite) from the deposits increase systematically from orebodies to the alkaline intrusions. All of these intrusion‐related gold deposits show relatively radiogenic lead isotopic compositions compared to mantle or lower crust curves. Most lead isotope data of sulfides from the gold ores plot in between the fields of the intrusions and Precambrian metamorphic rocks. Data are interpreted as indicative of a mixing of sulfur and lead from magma with those from Precambrian metamorphic rocks. Isotopic age data, geological and geochemical evidences suggest that the ore‐forming materials for the intrusion‐related gold deposits were generated during the emplacement of the Hercynian or Yanshanian intrusion. The calc‐alkaline or alkaline magma may provide heat, volatiles and metals for the intrusion‐related gold deposits. Evolved meteoric water, which circulated the wall rocks, was also progressively involved in the magmatic hydrothermal system, and may have dominated the ore fluids during late stage of ore‐forming processes. Therefore, the ore fluid may have resulted from the mixing of calc‐alkaline or alkaline magmatic fluids and evolved meteoric water. All these intrusion‐related gold deposits are believed to be products of Hercynian or Yanshanian calc‐alkaline and alkaline igneous processes along deep‐seated fault zones within the North China craton or along its marginal belts. 相似文献
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金厂沟梁—二道沟金矿田内花岗岩类侵入体锆石的离子探针U—Pb年代及意义 总被引：13，自引：5，他引：13
金厂沟梁-二道沟金矿田内花岗岩类侵入体SHRIMP锆石U-Ph定年结果表明,该区中生代以来到少经历了三次中酸性岩浆侵入作用,它们分别以西台子二长花岗岩、娄上含辉石石英闪长岩和西对面沟花岗闪长岩及闪长玢岩脉在218±4Ma(印支期)、161±1Ma(燕山早期)和126±1Ma(燕山晚期)的侵位为标志。花岗岩类的地球化学资料表明,这些花岗岩类侵入体形成与造山作用有关,为造山后或陆内拉张作用的产物。二道沟矿区成矿前或成矿期闪长玢岩脉的年龄126±1Ma限定了该区金矿化的最大年龄;结合前人有关年代学资料,认为本区金矿化应发生在126～118Ma。这说明金厂沟梁-二道沟金矿田的金矿床与我国胶东、小秦岭和辽东等地区的金矿床是同时形成的,再次证明燕山晚期是中国最重要而广泛的金成矿期。此外,在这些主要的金矿区内,金矿化时间上均具有与各自区内最晚一次花岗质岩浆作用同时或稍晚的特征,这可能指示金矿床是造山作用或区域构造-岩浆演化最晚期的产物。 相似文献
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The Liziyuan gold deposit, situated on the south side of the Shangdan suture zone, West Qinling Orogen, occurs in metamorphic volcanic rocks(greenschist facies) of the early Paleozoic Liziyuan Group and in Indosinian Tianzishan monzogranite. Orebodies in the Liziyuan gold field are controlled by the ductile-brittle shear zone, and by thrusting nappe faults related to the Indosinian orogeny. In detail, this paper analyzed the geological characteristics of the Liziyuan gold field, and the Pb isotopes of the Lziyuan host rocks, granitoids(Tianzishan monzogranite and Jiancaowan syenite porphyry), sulfides, and auriferous quartz veins by multiple-collector inductively coupled plasma mass spectrometry(MC-ICPMS). In addition, previous data on the sulfur, hydrogen, and oxygen isotopes were employed to discuss the possible sources of the ore-forming fluids and materials, and to further understand the tectonic setting of the Liziyuan gold deposit. The sulfides and their host rocks(Lziyuan Group), Tianzishan monzogranite and Jiancaowan syenite porphyry, and auriferous quartz veins have similar Pb isotopic compositions.Zartman's plumbotectonic model diagram shows that most of the data for the deposit fall near the orogenic Pb evolutionary curve or within the area between the orogenic and mantle Pb evolutionary curves. In the△β-△γ diagram, which genetically classifies the lead isotopes, most of the data fall within the range of the subduction-zone lead mixed with upper crust and mantle. This indicates that a complex source of the ore lead formed in the orogenic environment. The δ~(34)S values of the sulfides range from 3.90 to 8.50‰(average6.80‰), with a pronounced mode at 5.00‰-8.00‰. These values are consistent with that of orogenic gold deposits worldwide, indicating that the sulfur sourced mainly from reduced metamorphic fluids. The isotopic hydrogen and oxygen compositions support a predominantly metamorphic origin of the oreforming fluids, with possible mixing of minor magmatic fluids, but the late stage was dominated by meteoric water. The characteristics of the Liziyuan gold deposit formed in the Indosinian orogenic environment of the Qinling Orogen are consistent with those of orogenic gold deposits found worldwide. 相似文献