广东莲花山断裂带动力变质成矿作用新认识     

汪礼明  王军  王核  卜安  郭锐  王涌泉  朱沛云 《地质论评》2016,62(S1):90-92

广东莲花山断裂带是广东省内已知的最重要的锡、铜多金属成矿带。其南西段是莲花山国家级锡铜多金属整装勘查区,区内共分布有北山嶂—九龙嶂、棉洋—双华、五指嶂—锅子嶂、梅陇—鲘门—观音山4个动力变质带,动力变质带是本区内重要含矿及控矿构造。本文在野外地质调查、构造专项地质填图的基础上,通过对新发现的具有大型找矿前景的金坑铜锡多金属矿床的解剖,从矿区宏观地质特征、矿床的成矿温度、压力、成矿物质来源及成矿年龄等方面进行分析,认为矿床的成矿物质来源于侏罗纪火山岩;矿床的成矿作用主要与动力变质作用密切相关,为动力变质热液改造矿床;由此推测广泛分布于4个动力变质带中的诸多中、小型锡铜多金属矿床、地表矿化带（点）和化探异常的深部具有重要找矿潜力,具有大型矿床找矿前景。通过对本区的进一步工作,广东莲花山断裂带有望成为华南地区乃至全国重要的锡铜多金属成矿带。  相似文献   

朝鲜半岛北部显生宙花岗岩成因研究及地质意义   总被引：4，自引：3，他引：1  

张艳斌  吴福元  杨正赫  金正男  韩龙渊 《岩石学报》2016,32(10):3098-3122

朝鲜半岛北部图们江褶皱带和冠帽地块发育大面积的花岗岩,长期被认为形成于晚古生代二叠纪-早中生代三叠纪。采用锆石原位微区U-Pb测年技术(SIMS U-Pb),对6个代表性岩体的16个样品进行了侵位年龄测定,结合早期发表的年代学数据,确定朝鲜北部花岗岩主要形成于中生代的侏罗纪(199~173Ma),少部分为晚二叠世(265~263Ma)和早三叠世(248~240Ma)。岩石学及地球化学特征表明,朝鲜北部花岗岩以钙-碱性岩石系列为主,其成因类型为I型,且少数为高分异I型。锆石Hf-O同位素特征明显分为两类:图们江褶皱带及冠帽地块中的侏罗纪花岗岩、冠帽地块中晚二叠世片麻状花岗岩具有正的εH f(t)值(4.7~13.5)和年轻的二阶段Hf模式年龄(367~784Ma),O同位素组成δ~(18)O集中分布在5.7‰~7.4‰,表明其源区物质为新生地壳,且该地壳物质来自于亏损型的软流圈地幔;而冠帽地块中晚二叠世和早三叠世花岗岩通常具有负的εH f(t)值(-10.9~3.8)和古老的二阶段Hf模式年龄(889~1651Ma),O同位素组成变化较大,δ~(18)O分布在5.6‰~9.2‰,推测其主要为古老地壳物质重熔的产物。区域对比研究表明,图们江褶皱带和冠帽地块具有相同的地质演化历史,应归属于同一个整体,其上发育的花岗岩与我国吉黑造山带花岗岩在年代学格架、岩石学及地球化学特征、成因类型及岩浆源区都具有极大的相似性,可以进行对比。由此可见,朝鲜北部图们江褶皱带和冠帽地块为中亚造山带的组成部分,且朝鲜北部晚二叠世-早三叠世花岗岩形成于古亚洲洋闭合阶段,由于西伯利亚板块与华北板块的碰撞拼合,在华北地台北缘形成了同碰撞型花岗岩。侏罗纪中国东北及朝鲜开始进入环太平洋构造域演化阶段,在太平洋板块俯冲的挤压体制下形成大面积花岗岩。  相似文献   

腾冲地块晚白垩世-古近纪富锡花岗岩成因:岩浆源区及分异演化条件SCIEI北大核心CSCD     

崔晓琳  张琦玮  吴华英  宋志杰  张慧娟  戴荔果 《岩石学报》2022,38(1):253-266

腾冲地块锡成矿作用主要与晚白垩世-古近纪岩浆活动相关,但仅矿区花岗岩体具有较高的锡含量(平均25×10^(-6)),区域上同时代的非成矿花岗岩体并未发生锡的富集。本文通过搜集分析现有研究数据,总结了富锡成矿岩体和区域非成矿岩体在岩浆源区、演化条件和结晶分异程度的异同:区域非成矿岩体锆石ε_(Hf)(t)值(-15.1~+3.39)表明,自东北向西南幔源物质加入有升高的趋势,但区域玄武岩中低含量的Sn(1.61×10^(-6))表明幔源物质混入不利于岩浆中锡的富集。晚白垩世部分非成矿岩体与成矿岩体具有相同ε_(Hf)(t)(-9.7)值,表明其皆源于古老地壳物质的部分熔融,但岩体均表现为准铝质-弱过铝质特征,且锆石Hf同位素(t_(DM2)=1724Ma)和全岩Nd同位素(t_(DM2)=1836Ma)二阶段模式年龄基本一致,因此其源区可能并非富锡的高黎贡山群变质沉积岩,而可能是其中未经风化的变质花岗岩。根据腾冲地块地层厚度(28km)和莫霍面深度(47~35km)推断岩浆源区至少位于地下30km(8.4kbar),由于仅靠地温梯度(25℃/km)无法达到初始熔融温度(>1066℃),源区部分熔融过程很可能受地幔热的影响。根据Fe_(2)O_(3)/FeO比值,非成矿岩体(0.59)与成矿岩体(0.48)均具有较低的氧逸度,属钛铁矿系列,但成矿岩体的结晶分异程度明显高于非成矿岩体,且成矿岩体富含挥发分,高含量的挥发分降低了岩浆固结温度(650~550℃),延长了结晶分异时间,促进了锡在晚期岩浆中的富集。因此腾冲地块富锡花岗岩主要是普通岩浆在低氧逸度环境下发生高度结晶分异的结果。  相似文献   

印尼西婆罗洲早白垩世Mensibau花岗岩类的成因及构造意义     

郭东海  刘铁翊  朱俊宾  姜冠哲  李舢 《地质论评》2023,69(4):1249-1268

婆罗洲西部(印尼)在中生代期间处于特提斯构造域和古太平洋构造域交汇地带,是全球少有的多重板块动力学体制既有先后叠加又有同时复合的独特大地构造单元。因此,该区相关花岗岩类成因及构造背景的研究对揭示东南亚构造—岩浆演化历史及多重构造体制叠合造山作用下的岩浆演化机制至关重要。笔者等对西婆罗洲Mensibau岩基的花岗岩类进行了锆石U-Pb年代学、元素地球化学和Sr-Nd-Hf同位素分析。其中,石英二长岩和钾长花岗岩样品的LA-ICP-MS锆石U-Pb同位素年龄分别为126.9±2.1 Ma和141.8±2.6 Ma,表明岩体形成于早白垩世,岩浆活动至少持续了15 Ma。Mensibau花岗岩类具有高SiO₂(67.5%～73.3%)、高K₂O (4.3%～5.4%)和低P₂O₅(0.07%～0.14%)的元素含量特征,铝饱和指数(A/CNK)为0.92～1.06,并且含角闪石,属准铝质—弱过铝质I型花岗岩类。这些花岗岩类具有轻稀土元素(LREEs)富集和重稀土元素(HREEs)亏损,弱的负铕异常(δEu=...  相似文献   

Some Pertinent Features of Mo‐Mineralized Granitoids in the Circum‐Pacific Region     

Shunso Ishihara  Kezhang Qing 《Resource Geology》2014,64(4):367-378

Petrological characteristics of granitic rocks related to the world large molybdenum deposits are studied. The granitoids are evaluated by Fe₂O₃+TiO₂‐FeO+MnO‐MgO diagrams, and found to all plot to the magnetite‐series field. They are all high silica and high‐K series, but not A‐type, except for the Climax‐type porphyries and some others in the Colorado mineral belt. By‐product molybdenum contained in porphyry copper deposits, lower grade but huge tonnage, occurs with calc‐alkaline I‐type magnetite‐series granodiorite and monzogranite. Felsic intrusive rocks of the Climax mine are A‐type and are exceptionally high in trace elements such as F and Rb, which are generally enriched with W and Sn‐related granitoids that originated in crustal source rocks. The by‐product molybdenites in porphyry copper deposits appear to originate in adakitic granodiorite or monzogranite, having deep origins with the subducted slab or thickened juvenile mafic lower crust. Therefore, there is no single magma type but the magnetite series, which concentrates a large volume of molybdenum in the ore deposits.  相似文献   

Geochemistry,geochronology, and zircon Hf isotopes of Late Jurassic–Early Cretaceous granitoids in the Xing'an Massif,NE China: Implication for the Late Mesozoic tectonic evolution and crustal growth     

Hai-Na Li  Jun Han  Nuru Said  Zhi-Gang Yin 《Island Arc》2021,30(1):e12380

This paper presents new zircon U–Pb geochronological, Hf isotopic and whole-rock geochemical data for the granitic plutons in the Xing'an Massif, Northeast China, to constrain the Late Mesozoic tectonic evolution of the Mongol-Okhotsk Ocean and the Paleo-Pacific Ocean. The zircon U–Pb ages indicate that the granitoids emplaced during the Late Jurassic–Early Cretaceous. The granodiorites show an adakitic affinity with high Sr/Y ratios and low Yb (< 1.30 μg/g) contents. The monzogranites exhibit high SiO₂, low MgO contents, enrichment in LILEs (Rb, K, and Th), and depletion in HSFEs (Ta, Nb, Zr, P, and Ti). Petrological and geochemical features of these monzogranites suggest that they are highly fractionated I-type granitoids. In addition, the zircon ε_Hf(t) values and two-stage model ages (T_DM2 ) are in the range of +2.6 to +8.1 and 669–1011 Ma, respectively, indicating that primary magma was generated by partial melting of juvenile lower-crustal materials, and there was a significant crustal growth in the Phanerozoic in the Northeast China. Combined with the coeval granitoids widely exposed in the Xing'an Massif, we conclude that the Late Jurassic magma in Northeast China was generated in an extensional setting related to the closure of the Mongol-Okhotsk Ocean, but the Early Cretaceous magma was related to the subduction of the Paleo-Pacific Plate.  相似文献   

山东昌邑莲花山铁矿矿床地质与矿石稀土、微量元素特征     

王金辉  王巧云  刘汉栋  王立功 《岩石矿物学杂志》2014,33(2):355-364

莲花山铁矿位于昌邑-安丘铁成矿带的中部,铁矿体赋存于古元古代粉子山群小宋组中。本文通过矿石地球化学特征及其与矽卡岩矿物组合和赋矿围岩结构特征的对比研究,证明了莲花山铁矿与条带状铁矿相似。莲花山铁矿矿石稀土元素含量较低,经页岩标准化的稀土元素配分模式呈现轻稀土元素亏损、重稀土元素富集的特征,具有明显的Eu、Y、La异常,为无明显Ce异常,Y/Ho比值反映了在其沉积时受到海水作用的影响,表明莲花山铁矿的稀土元素来源于火山热液和海水的混合溶液。微量元素中Ti、V、Co、Ni、Mn、Sr、Ba等含量较低,原始地幔标准化的微量元素配分曲线显示,U、La、Hf呈正异常,Ba、Nb、Ta、Sr呈负异常,SiO2/Al2O3、Ti/V、Ni/Co、和Sr/Ba的比值指示了莲花山铁矿成矿物质来源于火山物质的沉积。研究结果表明,莲花山铁矿成矿作用源于火山热液与海水的混合,成矿物质来自火山沉积物,其地质与地球化学特征与五台山铁矿一致,为火山沉积变质型铁矿床。  相似文献   

内蒙古阿拉善盟北部宗乃山中酸性侵入岩年代学、地球化学及构造意义   总被引：4，自引：0，他引：4       下载免费PDF全文

史兴俊  张磊  王涛  肖序常  童英  张建军  耿建珍  叶珂 《岩石矿物学杂志》2014,33(6):989-1007

锆石LA-ICP-MS U-Pb测年结果表明,阿拉善盟北部宗乃山岩基包括中二叠世钾长花岗岩(272±1 Ma)和早三叠世闪长岩(249±1 Ma)、花岗闪长岩(247±1 Ma)。中二叠世钾长花岗属于准铝质和钾玄质系列,为高分异I型花岗岩。早三叠世闪长岩属钙碱性系列,而花岗闪长岩为弱过铝质,钙碱性系列,属于I型花岗岩。宗乃山地区这些中酸性侵入岩都显示出轻稀土元素相对富集和重稀土元素相对亏损的特征,并且具有微弱-中等的Eu负异常。在原始地幔标准化图解中,都相对富集大离子亲石元素(K、Rb、Ba和Sr等),亏损高场强元素(Ta、Nb、P和Ti等)。宗乃山地区侵入岩的锆石绝大部分具有正的εHf(t)值(+0.3~+11.6)和相对年轻的地壳模式年龄(tCDM=1 275~533Ma),表明源区主要为新生地壳物质。这些特征与同一构造带上沙拉扎山地区的侵入岩十分类似,而明显不同于具有古老基底的阿拉善地块内发育的侵入岩,因此宗乃山-沙拉扎山构造带具有亲中亚造山带的特征,中亚造山带与阿拉善地块的界线应位于宗乃山-沙拉扎山构造带以南。  相似文献   

Ag-Cu-Pb-Bi-S Minerals Newly Discovered from the Ohori Base Metal Deposit, Yamagata Prefecture, NE Japan: Implications for Bi-metallogenesis in the Green-Tuff Region     

Yu Yokoro    Kazuo Nakashima 《Resource Geology》2010,60(1):1-17

The Ohori deposit, one of the base metal deposits in the Green-Tuff region, NE Japan, is composed of two types of mineralization; a skarn-type (Kaninomata orebody) made by the replacement of the Miocene calcareous layer, and a vein-type (Nakanomata orebody). While the ore mineral assemblage of the deposit (chalcopyrite, pyrite, sphalerite and galena) has been known for being rather simple, some Pb-Bi-S minerals have been discovered for the first time in the present study. The minerals mainly occur in the chalcopyrite-rich ores of both orebodies. They essentially belong to the Pb-Bi-S system and contain Cu and Ag in minor amounts, which correspond to the lillianite–gustavite solid solution series (phases Z and X), cosalite, neyite, felbertalite, krupkaite and Bi-bearing galena. The chalcopyrite-rich (Bi-bearing) ores from both orebodies are richer in chalcopyrite, pyrite and chlorite, and have higher homogenization temperatures (>300°C) of fluid inclusions, and higher FeS contents in sphalerite compared to the Bi-free ores. In the Green-Tuff region, Bi-minerals have been reported from many base metal deposits. Most of these Bi-bearing ore deposits are referred to as xenothermal-type deposits, and are characterized by the following common features; composite mineralization of high- and low-temperatures in the shallower environments, and close relationships with the Tertiary granitic rocks. The whole mineralization at the Ohori deposit also has a similar xenothermal character because of the coexistence of high-temperature chalcopyrite-rich ores with Pb-Bi-S minerals, which were formed by the influence of the Tertiary granitic rocks at a shallow depth.  相似文献   

Long-lived Neoproterozoic high-K magmatism in the Pernambuco–Alagoas Domain,Borborema Province,northeast Brazil     

《International Geology Review》2012,54(10):1280-1299

The Pernambuco–Alagoas (PE–AL) Domain contains major granitic batholiths typified by a wide range of T_DM model ages (Archaean to Neoproterozoic), reflecting the important role of quartzofeldspathic plutons attending the Brasiliano (Pan-African) Orogeny. U/Pb zircon data for eight syn- to post-collision to syn-transcurrent granitic intrusions of the PE–AL Domain allow the studied plutons to be divided into two groups: (1) granitoids with crystallization ages older than 600 Ma (Água Branca, Serra do Catú, Serra da Caiçara, and Mata Grande plutons) and (2) granitoids with ages of ca. 590 Ma (Correntes, Águas Belas, Viçosa, and Cachoeirinha plutons). The intrusions of group 1, except for the Mata Grande Pluton, all show Nd T_DM model ages ranging from 1.5 to 1.2 Ga, whereas the granitoids from group 2 and the Mata Grande Pluton have Nd T_DM model ages ranging from 2.2 to 1.7 Ga. The studied granitoids are in part high-K, calc-alkaline, shoshonitic, and in part transitional high-K calc-alkaline to alkaline in terms of their bulk chemistry. Volcanic arc signatures associated with the Palaeoproterozoic T_DM model ages are interpreted as inherited from the source rocks. The oldest ages and higher Nd T_DM model ages recorded in the granitoids intruded in the southwestern part of the PE–AL Domain suggest that these intrusions are associated with slab-tearing during convergence between the PE–AL and Sergipano domains. The investigated plutons are coeval with high-K granitoids intruded within the Transversal Zone Domain of Borborema Province and calc-alkaline granitoids of the Sergipano Domain. This suggests that these geologic realms belonged to the same crustal block during the Brasiliano Orogeny. However, such large volumes of high-K granitoids with crystallization ages older than 600 Ma are not recorded in the Sergipano and Transversal Zone domains, suggesting differences in the crustal evolution of these three areas.  相似文献