中国南方离子吸附型稀土矿床成矿类型及其母岩控矿因素探讨     

付伟  赵芹  罗鹏  李佩强  陆济璞  周辉  易泽邦  许成 《地质学报》2022,96(11):3901-3923

传统认为中国南方的离子吸附型稀土矿床可划分为以“足洞式”为代表的重稀土型和以“河岭式”(或“花山式”)为代表的轻稀土型两种矿化类型。然而，近年来发现的许多矿床(如清溪、寨背和馒头山等)的赋矿风化壳中出现了轻稀土矿与重稀土矿并存现象，表现出特殊的“上轻下重”双层矿体结构。这指示了除重稀土型和轻稀土型之外，还存在着轻重稀土共生型的过渡类型。本研究通过对三种不同成矿类型的若干典型矿床系统对比，指出成矿类型的多样性与母岩性质密切相关，尤其是母岩的稀土元素地球化学和稀土载体矿物属性是制约成矿类型变化的关键因素。统计数据表明，从重稀土型→轻重稀土共生型→轻稀土型，成矿母岩的全岩稀土总量变化不大(ΣREY: 200×10-6~450×10-6→200×10-6~500×10-6→200×10-6~800×10-6)，但轻重稀土配分值出现较显著的区间性差异(ΣLREE/ΣHREY: 02~1→1~5→2~10)。与之同时，母岩中能为离子相稀土提供物源且具有重稀土配分属性的稀土副矿物类型和数量明显减少，这与全岩稀土元素地球化学特征中重稀土分量占比的降低趋势也互相匹配。该结果指示，以往认为重稀土配分母岩形成重稀土矿床、轻稀土配分母岩形成轻稀土矿床的传统观点需要外延，即一部分具有低度轻稀土配分属性(1＜ΣLREE/ΣHREY＜5)且含有丰富易风化稀土副矿物的母岩还可能形成轻重稀土共生型矿床，该认识可为今后离子吸附型稀土矿床勘查工作提供新的找矿依据。  相似文献   

Are the South and North Liaohe Groups of North China Craton different exotic terranes? Nd isotope constraints   总被引：29，自引：1，他引：29  

Sanzhong Li  Guochun Zhao  Min Sun  Zongzhu Han  Guangtao Zhao  Defeng Hao 《Gondwana Research》2006,9(1-2):198

The Liaohe Group is an important Paleoproterozoic stratigraphic unit in the northeastern part of the North China Craton and is traditionally subdivided into the North and South Liaohe Groups. Associated with both the North and South Liaohe Groups are voluminous Paleoproterozoic granitoid rocks, named the Liaoji granitoids. Different tectonic models, including terrane amalgamation, continent–arc collision and rift closure, have been proposed to interpret the tectonic setting and evolution of the North and South Liaohe Groups and associated Liaoji granitoids. At the centre of the controversy between these models is whether or not the North and South Liaohe Groups developed on the same Archean basement. Nd isotopic geochemistry of the Liaoji granitoids provides important constraints on this controversial issue. The Liaoji granitoids associated with the North and South Liaohe Groups display similar ε_Nd values, restricted to a narrow range from 0 to 2, implying that these granitoid rocks were derived from the same or a similar magma source. Moreover, the Liaoji granitoids associated with the North and South Liaohe Groups have similar Nd model ages (T_DM), ranging from 2.4 to 2.6 Ga, suggesting that the protoliths of the Liaoji granitoids associated with both groups may have formed simultaneously, and that the basement rocks underneath the Liaoji granitoids and associated North and South Liaohe Groups belong to the same continental block rather than two different blocks. Combining lithological, structural and geochronological considerations, we interpret the North and South Liaohe Groups as having developed on a single late Archean basement that underwent Paleoproterozoic rifting associated with the intrusion of the Liaoji granitoids and the formation of the Liaohe Group, and closed upon itself in the Paleoproterozoic.  相似文献   

Petrogenesis and tectonic setting of Cadomian felsic igneous rocks, Sandıklı area of the western Taurides, Turkey     

Semih Gürsu  M. Cemal Göncüoglu 《International Journal of Earth Sciences》2006,95(5):741-757

In the Sandıklı (Afyon) region, western Taurides, the Late Proterozoic rocks of the Sandıklı basement complex are composed of low-grade meta-sedimentary rocks (Güvercinoluk Formation) intruded by felsic rocks (Kestel Cayı Porphyroid Suite, KCPS). The KCPS is a deformed and highly sheared, dome-shaped rhyolitic body with a granitic core. Quartz porphyry dikes intrude both the slightly metamorphic igneous and the sedimentary rocks of the basement complex. Both the quartz porphyries and rhyolites were converted into mylonites with relict igneous textures. Geochemical data show that these felsic igneous rocks are subalkaline and mainly granitic in composition with SiO₂ >72 wt% and Al₂O₃ >11.5 wt%. The chondrite-normalized incompatible trace element patterns are characterized by distinct negative Rb, Nb, Sr, P, Ti, and Eu with enrichment in Th, U, La, Ce, Nd, Sm, and Zr. The REE patterns of the felsic rocks indicate a strong enrichment in LREE but display slightly flat HREE patterns. According to geochemical characteristics and petrogenetic modeling, extrusive and intrusive rocks of the KCPS were probably derived from an upper continental crustal source (partial melting of granites/felsic rocks) by 18–20% fractional melting plus 18–20% Rayleigh fractional crystallization, which seems to be the most effective igneous process during the crystallization of the KCPS. Single zircon age data from the granitoids and fossils from the disconformably overlying sedimentary successions indicate that the metamorphism and the igneous event in the Taurides are related to the Cadomian orogeny. Based on the geological, geochemical and petrogenetic correlation of the post-collisional granitoids it is further suggested that the Tauride belt in western central Turkey was in a similar tectonic setting to the Gondwanan terranes in North Africa (Younger Granitoids) and southern Europe (Spain, France, Bohemia, Brno Massifs) during the Late Cadomian period.  相似文献   

浙江洪公铝质A型花岗岩类的岩石地球化学及其构造环境   总被引：8，自引：0，他引：8  

卢成忠  汪庆华  董传万  董学发 《高校地质学报》2006,12(4):500-506

初步研究表明，以往被认为是典型的I型花岗岩质岩石的浙江洪公岩体应为铝质A型花岗岩质岩石。该岩体以高钾为特征，K2O 达5％以上，K2O/ Na2O＞1.2，准铝-过铝质（A/NKC=0.80 ～1.14）；FeO*/MgO比值大（平均14.20）,高于M型、S型和I型花岗岩；富含稀土元素（ΣREE=313.09×10-6～523.73×10-6），具有较高的Ga/Al（′104）值（2.92～4.29）和（Zr+Nb+Ce+Y）元素组合值（551.5′10－6～987.4′10－6），而亏损Ba、Sr、P、Ti等；Nd同位素模式年龄为1.3—1.6Ga，反映洪公岩体主要起源于地壳物质的部分熔融。区域背景、构造被动定位特点和地球化学综合分析表明，洪公岩体形成于拉张的构造环境。  相似文献   

Zircon LA-ICP-MS U-Pb age, Ce^4＋/Ce^3＋ ratios and the geochemical features of the Machangqing complex associated with copper deposit     

梁华英  喻亨祥  莫测辉  张玉泉  谢应雯 《中国地球化学学报》2006,25(3):223-229

1IntroductionQuite a number of porphyry copper deposits havebeen found in the Cenozoic alkali-intrusions along theJinshajiang-Ailaoshan-Red River fault zone,whichconstitute the Cenozoic ore belt in China.The Cenozo-ic alkali-intrusive rocks are similar in…  相似文献   

甘肃花岗岩类成矿作用研究与找矿方向   总被引：4，自引：0，他引：4  

殷先明  杜玉良  殷勇 《西北地质》2005,38(4):25-31

甘肃省花岗岩分布广泛，与其有关的矿产资源也十分丰富。笔者将甘肃省划分为北山、敦煌一阿拉善、祁连山及西秦岭4个构造-花岗岩-矿化区；进一步在北山、祁连山及西秦岭3个区划分出20个构造-花岗岩-矿化带；并就加强花岗岩成矿作用的研究和找矿工作提出了具体的工作思路与建议。  相似文献   

西藏尼雄岩体岩石地球化学特征及其成因探讨   总被引：9，自引：0，他引：9       下载免费PDF全文

吴旭铃  陈振华 《中国地质》2005,32(1):122-127

尼雄岩体分布于西藏自治区措勤县木质顶、尼雄、沙松、日阿一带，出露面积180．14km^2，由4个深成岩体组成，平面形态呈不规则椭圆形、圆形串珠状分布，岩石类型有苏长岩、花岗闪长岩、二长花岗岩、花岗岩。根据野外地质调查资料和室内的岩石学、岩石化学等特征的综合研究成果，发现该岩体各单元之间呈脉动式侵入接触，接触界线清晰，且含有较多暗色闪长质微粒包体；稀土总量较低，K、Rb、Ba、Th元素相对富集，Cr、Ti、Nb、Sr、Zr、P元素相对亏损。研究显示尼雄岩体形成于活动陆缘火山弧，构造环境，与雅鲁藏布江大洋板块向北俯冲消减作用有关，为大陆弧花岗岩。  相似文献   

内蒙古中部苏尼特左旗富钾花岗岩锆石SHRIMP U-Pb年龄   总被引：12，自引：3，他引：12  

石玉若  刘敦一简平　张旗张福勤  苗来成施光海  张履桥陶华 《地质通报》2005,24(5):424-428

精确的锆石SHRIMP U-Pb年龄测定表明,内蒙古苏尼特左旗富钾花岗岩的结晶年龄分别为423Ma±8Ma和424Ma±10Ma.综合区域资料,认为该年龄代表了内蒙古中部志留纪期间发生弧-陆碰撞事件的时限.  相似文献   

西藏甲马铜多金属矿床远景预测   总被引：4，自引：5，他引：4  

任云生  张金树等 《地质与勘探》2002,38(5):30-32,43

近年研究表明，作为西藏境内少数几个大型矿床之一的甲马铜多金属矿床先后经历了燕山晚期海底喷流积积成矿作用和喜马拉雅期斑岩型成矿作用，相应形成矿区层状主矿休和斑岩型矿体。矿区地质特征、主成矿元素空间分布规律分析后认为：矿区东、西段各存在一个喷流中心，与之相关的层状矿体及深部脉状、网脉状矿体是今后找矿的重点靶区；喜马拉雅期斑岩成矿作用在区域及矿区内均有显示，具有不可忽视的成矿潜力。  相似文献   

新疆东天山斑岩型铜矿带及其大地构造格局   总被引：74，自引：6，他引：74       下载免费PDF全文

芮宗瑶  刘玉琳  王龙生  王义天 《地质学报》2002,76(1):83-94

新疆哈密南部发现的土屋、延东大型斑岩铜(钼)矿床,构成了东天山斑岩铜矿带。其中成矿的斜长花岗斑岩同位素年龄为369～356 Ma(Rb-Sr等时线法和单颗粒锆石U-Pb法),辉钼矿的同位素年龄为320 Ma(Re-Os等时线法),蚀变岩的同位素年龄为341～310Ma,含矿围岩由粗面质玄武岩到粗安岩,可能属于泥盆纪(416Ma,Sm-Nd法;>356 Ma、390 Ma、440 Ma,单颗粒锆石U-Pb法)。矿床成因归属为岛弧火山—深成作用产物。斑岩铜矿带的南部为著名的康古尔塔格金矿带,再往南为星星峡银矿带。这些造山带矿床组合由北而南构成斑岩型铜(钽)矿带→韧性剪切带型和浅成热液型金矿带→浅成热液型(构造蚀变带型)钼矿带,显示了构造岩浆是由北而南下插的,岩浆侵位时间北老南新,花岗质岩浆源区的部分熔融深度由北而南加深。反映壳幔演化的东天山构造岩浆作用从370 Ma到240 Ma、从北部的哈尔里克和康古尔塔格到南部的中天山,似乎存在一个连续的花岗质岩浆演化带,丝毫看不到深部作用过程由于古生代东天山数度拉张沦为海槽而被中断的迹象。基于以上主要证据,本文综合讨论了东天山斑岩型铜矿、韧性剪切带型金矿和构造蚀变带型银矿的形成机制及其大地构造格局,建立了东天山造山带的成矿模型,为今后找矿开辟了新方向。  相似文献