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1.
北阿尔金西段出露大量中酸性侵入岩,为探讨西段地区花岗质岩石的成因、形成环境以及北阿尔金地区岩浆活动特点,本文选取北阿尔金西段的正长花岗岩体和闪长岩体作为研究对象,进行了岩石学、地球化学、锆石U-Pb年代学及Hf同位素等方面的研究。研究结果表明,正长花岗岩体形成时代为495.7～502.0Ma,铝饱和指数A/CNK为0.86～1.09小于1.1,P_2O_5与Si O_2含量呈负相关,具I型花岗岩特征。轻稀土富集而重稀土亏损,具有明显的负Eu异常,微量元素特征显示富集Rb、Ba、Th、U、K等元素,相对亏损Nb、Ta、P、Ti等元素。岩石地球化学及锆石Hf同位素特征暗示其源区物质成分不均一,源岩主要为0.95～1.4Ga的新生地壳(变中基性岩),并有1.42～1.83Ga的古老地壳物质的参与。闪长岩体的侵位时代为497.1±3Ma,轻稀土富集而重稀土亏损,较弱的负Eu异常,相对富集Rb、Ba、Th、U、K等元素,而亏损Nb、Ta、P、Ti。锆石ε_(Hf)(t)值为-1.61～+2.16,二阶段模式年龄t_(DM2)为1.34～1.56Ga,暗示其源岩可能主要为新生地壳,并有古老地壳物质参与成岩。北阿尔金西段正长花岗岩、闪长岩均形成于早古生代,具弧型花岗岩特点,结合区域构造背景,认为其形成可能与北阿尔金洋壳俯冲有关,产于陆弧环境。 相似文献
2.
桃村坝花岗岩体位于粤北贵东复式花岗岩体中部。锆石U-Pb年龄为161.5±1.8 Ma (MSWD=1.7),属于燕山早期岩浆
活动产物。该岩体具有稍低的硅、富铝、富碱、钾大于钠、贫钙镁和高FeO*/MgO等特征。富集Rb,Th,U而亏损Ba,
Sr,Ti和Nb;LREE富集(LREE/HREE=7.39~16.4, (La/Yb)N=8.79~25.5),Eu亏损较为明显(δEu=0.44~0.59);Ga/Al比值较高(平
均值为2.99),Zr+Nb+Ce+Y含量(平均为518×10-6)大于350×10-6,可归属于A2型花岗岩;εNd(t)值低,为-9.7~-8.95,Nd模式
年龄为1.66~1.76 Ga;锆石的εHf(t)值为-20.0~-14.6,相应的Hf模式年龄为2.12~2.46 Ga。综合以上特征表明桃村坝花岗岩是
在地壳伸展-减薄的构造背景下、由古元古代地壳组分部分熔融的方式形成。 相似文献
3.
华北克拉通东部造山带内古元古代中期(2.1～2.2Ga)岩浆记录了造山带早期重要的地壳演化信息,对探讨辽吉造山带古元古代地质演化过程具有十分重要的意义。本文选择了辽东黑沟地区古元古代碱长花岗岩进行岩石学、地球化学、锆石U-Pb年代学和Hf同位素研究。黑沟碱长花岗岩LA-ICP-MS锆石U-Pb测年结果为2186.5±6.5Ma,形成时代为古元古代。岩石为碱性、弱过铝质A型花岗岩,岩石富硅、碱,贫钙、镁、铝,极度富钠贫钾,富集Hf、Zr、Nb、Y等高场强元素,亏损Rb、K、Ba等大离子亲石元素,具有较高的(K_2O+Na_2O)/Al_2O_3、FeO~T/MgO、Ga/Al比值,负的Eu异常,稀土元素配分曲线呈右倾海鸥型配分模式。锆石饱和温度介于857～884℃之间,同时具有非常低Sr高Yb特征,指示岩石形成于低压高温的伸展构造背景。锆石ε_(Hf)(t)值为-0.96～+4.58,二阶段模式年龄t_(DM2)=2476～2821Ma,明显大于花岗岩的成岩时代,结合岩石地球化学特征指示黑沟碱长花岗岩岩浆源于太古宙TTG片麻岩在地壳浅部伸展条件下的部分熔融。综合区域已有的岩石学、地球化学和同位素特征等资料,辽吉地区在古元古代早期可能处于大陆弧后盆地构造环境,黑沟碱长花岗岩是弧后盆地伸展环境下的产物。 相似文献
4.
蚌埠隆起区古元古代钾长花岗岩的成因: 岩石地球化学、锆石U-Pb年代学与Hf同位素的制约 总被引：11，自引：0，他引：11
对蚌埠隆起区庄子里和磨盘山钾长花岗岩进行了系统的年代学和地球化学以及锆石Hf同位素的研究, 以便对其岩石成因进行约束.研究结果表明, 庄子里和磨盘山钾长花岗岩中锆石发育震荡生长环带, 且具有较高的Th/U比值(0.13~1.47), 反映了岩浆成因特征.对庄子里和磨盘山钾长花岗岩中岩浆锆石进行的LA-ICP-MSU-Pb定年结果(上交点年龄) 分别为2104±20Ma和2196±190Ma, 这表明蚌埠隆起区钾长花岗岩的形成时代为古元古代.钾长花岗岩的SiO2和K2O含量分别介于69.65%~77.95%和4.98%~5.17%之间; 该类岩石富集轻稀土元素和Zr、Hf、Rb、Th、U等元素, 明显亏损Ba、Sr、Eu、P和Ti等元素; 它们的εNd(t) 值变化于-3.4~+3.2之间, Nd的模式年龄变化于2.31~2.79Ga之间; 钾长花岗岩中锆石的εHf(t) 值和Hf同位素两阶段模式年龄分别介于-5.1~+7.8和2.26~2.83Ga之间.上述特征表明, 蚌埠隆起区钾长花岗岩的原始岩浆起源于有少量古老地壳物质涉入的新生下地壳的部分熔融.庄子里和磨盘山钾长花岗岩为A型花岗岩, 形成于伸展的构造背景. 相似文献
5.
滇东北下田坝花岗岩的SiO2质量分数在71.1%～78.15%之间,Al2O3值在11.55%～14.90%之间,A/CNK=0.94～1.25,属于弱过铝质花岗岩。稀土元素总量(∑REE)为259.71×10-6～804.60×10-6,∑LREE/∑HREE为4.12～10.28,说明轻稀土较重稀土富集。岩石具有明显的负Eu异常(δEu=0.04～0.07),大离子亲石元素Rb、Ba、Pb、U等相对富集,高场强元素Nb、Ta、Zr、Ti等明显亏损,这些特征说明下田坝花岗岩是由壳源物质部分熔融形成的,具有A型花岗岩的特征。对下田坝花岗岩进行的激光探针等离子体质谱(LA-ICP-MS)锆石U-Pb同位素年代学研究获得了206Pb/238 U加权年龄年龄769±4.4Ma(MSWD=0.45),可代表花岗岩的形成年龄,下田坝花岗岩并非原来认为的早古生代花岗岩。结合对区域地质资料的分析认为,下田坝花岗岩的形成年龄与扬子地块西部Rodinia超大陆裂解事件在时间上一致,该花岗岩是在Rodinia超大陆裂解过程中由地幔柱活动引起的大陆裂谷环境中形成的,这也证实了扬子地块西南缘新元古代的裂谷环境已影响到滇东北的东川地区。 相似文献
6.
福州复式岩体I-A型复合花岗岩的岩石成因与源区性质目前尚未得到很好认识。本文对福州复式岩体花岗岩进行了岩石学、锆石U-Pb年代学、主量和微量元素地球化学及锆石Hf同位素研究。该复式岩体花岗岩可分为钙碱性和碱性系列。LA-ICP-MS锆石U-Pb定年结果表明,钙碱性系列花岗岩形成年龄为111～101Ma,是早白垩世多期次岩浆活动作用的产物;碱性系列花岗岩形成的年龄为95～93Ma,是晚白垩世岩浆活动的产物。两类岩石均具有Eu负异常、LREE富集和HREE亏损的特征,并且Rb、Th、U、K、Pb等大离子亲石元素相对富集,Ba、Sr以及高场强元素Nb、Ta、P、Ti相对亏损。其中,钙碱性系列花岗岩的轻重稀土分馏程度较之碱性系列花岗岩明显,而碱性系列花岗岩的负铕异常比钙碱性系列花岗岩明显。锆石Hf同位素组成表明,钙碱性系列花岗岩的ε_(Hf)(t)值为-3.9～0.2,地壳模式年龄表明花岗质岩浆源岩来自于新元古代古老地壳的部分熔融,并有少量的地幔组分卷入。碱性系列花岗岩的ε_(Hf)(t)值为0.04～4.8,地壳模式年龄指示花岗质岩浆源岩来自于新元古代古老地壳的部分熔融,并有大量幔源组分的混入。综合分析表明,福州复式岩体I-A型复合花岗岩具有相同的源区,其形成的差异主要是构造环境的变迁、幔源岩浆的加入以及岩浆分异演化等多种因素综合作用的结果。 相似文献
7.
文章对位于南岭西段湘桂交界处的都庞岭东侧岩体开展了锆石SHRIMP U-Pb年代学、岩石学、矿物化学、岩石地球化学和Sm-Nd、Lu-Hf同位素分析研究。锆石SHRIMP U-Pb定年结果显示,粗中粒斑状黑云母二长花岗岩年龄为215.6±2.1 Ma,中粒斑状黑云母二长花岗岩年龄为220.5±1.8 Ma,中粒环斑黑云母二长花岗岩年龄为222.8±1.5 Ma,结合以往研究获得的细粒白云母二长花岗岩年龄209.7±3.1 Ma,认为岩体侵位时限介于222.8~209.7 Ma,为印支期岩浆活动产物,非以往认为的燕山期。环斑钾长石、黑云母聚晶的矿物化学特征表明环斑黑云母二长花岗岩形成过程中岩浆温度、压力、成分发生震荡变化,在玄武质岩浆的底侵作用下发生多次熔融作用形成黑云母聚晶。都庞岭黑云母二长花岗岩具有较高的SiO2和K2O+Na2O含量,A/CNK值为1.02~1.39,里特曼指数(δ)为0.93~2.18,属过铝质钙碱性系列;微量元素地球化学性质表现为富集REE、Rb、Th和U及较高的HFSE(Nb、Y和Ga),亏损Ba、Sr、Eu,具有高的TFeO/MgO、Ga/Al比值,地球化学特征显示为A型花岗岩;Nd同位素εNd(t)值为-8.74~-8.13,T2DM值为1.71~1.66 Ga;锆石Hf同位素εHf(t)值为-14.1~-1.4,T2DM值为2.14~1.34 Ga,显示都庞岭黑云母二长花岗岩主要源于古老地壳物质的部分熔融,并受到了一定程度的亏损地幔物质的混染。印支运动的变质峰期在258~243 Ma,233 Ma以后华南地区处于伸展的构造背景并受到幔源玄武质岩浆大范围底侵,诱发地壳物质重熔形成伸展背景下的都庞岭印支期铝质A型(环斑)花岗岩。 相似文献
8.
北山柳园地区双峰山早泥盆世A型花岗岩的确定及其构造演化意义 总被引：11，自引：0，他引：11
北山柳园地区分布有大量的早中古生代花岗岩类岩石.柳园双峰山岩体具有高硅、高碱(AR=3.99～5.05,NK/A>0.85)、高FeOT/MgO比值和10 000×Ga/Al值、低Al2O3、贫CaO和MgO的特征,显示出准铝质、碱质花岗岩的特点;∑REE较高,LREE略富集,轻重稀土元素分馏不十分明显,Eu负异常明显;相对富集Rb、K、Pb等大离子亲石元素(LILE),强烈亏损Ba、Sr、P、Eu、Ti,弱亏损Ta、Nb等元素;同时具有较高的Rb/Nb和Y/Nb比值,显示了A2型铝质花岗岩的特征.采用LA-ICP-MS锆石U-Pb定年方法,获得双峰山岩体的206Pb/238U年龄为415±3 Ma(MSWD=1.5),代表该岩体的形成年龄,即双峰山岩体形成于早泥盆世.地球化学及Nd同位素特征综合分析显示,该岩体可能由幔源岩浆底侵导致上覆地壳物质(可能由洋壳和岛弧建造组成)部分熔融形成的花岗闪长质岩浆经进一步结晶分异作用形成,为该区较早的钙碱性花岗岩演化到后期的产物.岩体特征、年代学、地球化学和地质背景综合分析结果表明,该岩体形成于后造山或造山作用演化晚期阶段.双峰山早泥盆世A型花岗岩为目前北山地区发现的最老的A型花岗岩,这对探讨古生代花岗岩成因类型及岩浆演化具有重要的意义. 相似文献
9.
大兴安岭地区晚中生代的大地构造背景一直存在争议,通过对内蒙古巴林右旗胡都格绍荣岩体进行锆石U-Pb测年、岩石地球化学以及锆石Lu-Hf同位素分析,探讨其形成时代及构造背景.胡都格绍荣岩体主体岩性为似斑状黑云母二长花岗岩,LA-ICP-MS锆石U-Pb测年确定其加权平均年龄为129.9±1.4 Ma(MSWD=0.91),指示其侵位于早白垩世.花岗岩具有高SiO2、Na2O、K2O含量,低CaO、MgO含量,富集Cs、Rb、K、Th、U、Zr,亏损Ba、Sr、P、Ti,轻稀土富集,具明显Eu负异常(δEu=0.35~0.44),10 000×[w(Ga)/w(Al)]为2.08~3.05,表明其为典型的A型花岗岩.Hf同位素分析结果显示,锆石具有正的εHf(t)值(2.24~9.41),Hf两阶段模式年龄为1 030~570 Ma,平均为809 Ma,结合其微量元素特征,认为岩浆来源于新元古代地壳的部分熔融.胡都格绍荣花岗岩指示研究区在早白垩世为伸展构造背景,可能与蒙古-鄂霍茨克洋闭合关系更为密切. 相似文献
10.
西藏冈底斯西部江巴、邦巴和雄巴岩体的锆石U-Pb年代学与Hf同位素地球化学 总被引：11，自引：6，他引：5
对青藏高原冈底斯带西部中生代花岗岩的研究依然十分有限。本文选择青藏高原冈底斯带西部狮泉河-革吉-雄巴地区的三个花岗岩基进行了锆石SHRIMP U-Pb定年和锆石Hf同位素分析,并探讨了中冈底斯带中侏罗世-早白垩世花岗岩的分布特征及其揭示的地壳基底的属性。定年结果表明,江巴岩体花岗闪长岩年龄为170±3Ma,雄巴岩体碱长花岗岩年龄为149±3Ma,它们形成于中晚侏罗世;邦巴岩体寄主岩石正长花岗岩和其中的石英二长闪长岩包体年龄分别为144±3Ma和133±3Ma,形成于早白垩世。锆石Hf同位素和地壳模式年龄结果表明,中晚侏罗世的江巴岩体(εHf(t)为-16.8～-13.4,Hf同位素地壳模式年龄为2.1～2.3Ga)与雄巴碱长花岗岩(-11.3～-6.2和1.6～2.0Ga)具有富集的Hf同位素特征,显示了新元古界的地壳基底年龄。邦巴正长花岗岩(-4～-0.8和1.2～1.5Ga)与其中的闪长质包体(-2.8～+0.6和1.2～1.4Ga)具有一致的Hf同位素特征,显示了岩浆混合作用。本文花岗岩定年与Hf同位素结果进一步揭示出中冈底斯带存在未出露地表的古元古代地壳基底。 相似文献
11.
S. Viswanathan K. Surya Prakash Rao B. Mahabaleswar 《Journal of the Geological Society of India》2013,82(6):621-627
Komatiites are mantle-derived ultramafic volcanic rocks. Komatiites have been discovered in several States of India, notably in Karnataka. Studies on the distribution of trace-elements in the komatiites of India are very few. This paper proposes a simple, accurate, precise, rapid, and non-destructive wavelength-dispersive x-ray fluorescence (WDXRF) spectrometric technique for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in komatiites, and discusses the accuracy, precision, limits of detection, x-ray spectral-line interferences, inter-element effects, speed, advantages, and limitations of the technique. The accuracy of the technique is excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Zr, Nb, Ba, Pb, and Th and very good (within 4%) for Y. The precision is also excellent (within 3%) for Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th. The limits of detection are: 1 ppm for Sc and V; 2 ppm for Cr, Co, and Ni; 3 ppm for Cu, Zn, Rb, and Sr; 4 ppm for Y and Zr; 6 ppm for Nb; 10 ppm for Ba; 13 ppm for Pb; and 14 ppm for Th. The time taken for determining Sc, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Ba, Pb, and Th in a batch of 24 samples of komatiites, for a replication of four analyses per sample, by one operator, using a manual WDXRF spectrometer, is only 60 hours. 相似文献
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E. M. Prasolov S. A. Sergeev B. V. Belyatsky E. S. Bogomolov K. A. Gruzdov I. N. Kapitonov R. Sh. Krymsky V. O. Khalenev 《Geochemistry International》2018,56(1):46-64
This paper reports the first results of a study of 11 isotope systems (3He/4He, 40Ar/36Ar, 34S/32S, 65Cu/63Cu, 62Ni/60Ni, 87Sr/86Sr, 143Nd/144Nd, 206–208Pb/204Pb, Hf–Nd, U–Pb, and Re–Os) in the rocks and ores of the Cu–Ni–PGE deposits of the Norilsk ore district. Almost all the results were obtained at the Center of Isotopic Research of the Karpinskii All-Russia Research Institute of Geology. The use of a number of independent genetic isotopic signatures and comprehensive isotopic knowledge provided a methodic basis for the interpretation of approximately 5000 isotopic analyses of various elements. The presence of materials from two sources, crust and mantle, was detected in the composition of the rocks and ores. The contribution of the crustal source is especially significant in the paleofluids (gas–liquid microinclusions) of the ore-forming medium. Crustal solutions were probably a transport medium during ore formation. Air argon is dominant in the ores, which indicates a connection between the paleofluids and the atmosphere. This suggests intense groundwater circulation during the crystallization of ore minerals. The age of the rocks and ores of the Norilsk deposits was determined. The stage of orebody formation is restricted to a narrow age interval of 250 ± 10 Ma. An isotopic criterion was proposed for the ore-bearing potential of mafic intrusions in the Norilsk–Taimyr region. It includes several interrelated isotopic ratios of various elements: He, Ar, S, and others. 相似文献
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奥地利安东帕有限公司 《岩矿测试》2009,28(3):306-306
最新的流行病学研究表明,空气中较高浓度的悬浮细颗粒可能对人类的健康有不利的影响。根据该项研究显示,由于心脏病、慢性呼吸问题和肺功能指标恶化而导致死亡率的升高与细尘粒子有关。这些研究结果已经促使欧盟于1999年4月出台了限制空气中二氧化硫、二氧化氮、氧化氮、铅和颗粒物含量的法案(1999/30/EC),对各项指标包括对可吸入PM10颗粒的浓度提出了新的限制性指标。PM10颗粒是指可以通过预分级器分离采集的气体动力学直径小于10μm的细颗粒。目前研究的兴趣重点逐步偏向PM2.5这些更细微颗粒物,PM2.5这种颗粒物对健康有明显的不利影响。在欧盟指令2008/50/EC中,对PM10和PM2.5都提 相似文献
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Mining induced subsidence can significantly affect mining costs where major surface facilities and natural environment need to be protected. Overburden grout injection is a technology used to control coal mine subsidence by injecting the mine waste material extracted from the coal back into the inter-burden rock during longwall mining. The flowing slurry is here categorised as a nonlinear viscous cohesive (Bingham plastic) fluid. During longwall mining the grout slurry is pumped into the separated beds of the rock mass through a central vertical borehole, which is drilled deep into the inter-burden rock strata above the coal seam. However, a blockage can occur in the injection system when the slurry velocity falls below a certain critical threshold velocity, indicating a material phase change from cohesive-viscous to cohesive-frictional. In situ field injection tests through boreholes have been simulated at a smaller scale at the CSIRO laboratory in Brisbane by pumping the slurry through a radial disk (gap = 4 mm) from its centre. Laboratory experiments indicate a general, nonlinear, cohesive, viscous, frictional model for shear behaviour of the slurry, in which the material shear parameters are functions of the disk radial distance. Complete dimensional and dimensionless analytical solutions have been developed based on an approach related to Bingham–Herschel–Bulkley fluid mechanics. The derived formulae include relations for minimum pump pressure, local pressure and pressure gradient, wall shear stress, volume rate, velocity and velocity gradient. The theoretical results match the experimental measurements. The experiments covered slurries with maximum particle sizes of 0.5 to 2 mm with about 50% being larger than 100 µm. The viscosities at the various solids concentrations were measured with a standard torsion viscometer. This study differs from the previous research in several distinct aspects, namely, consideration of the variable shear parameters rather than fixed values, inclusion of total nonlinear behaviour, and implementation of a friction function to mimic behaviour of the deposited and consolidating stiff slurry, which can cause a significant pressure rise as a result of the increased shear resistance. 相似文献
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Alexander E. C. Broberg J. S. Kehren A. R. Graziani M. M. Turri W. L. 《Environmental Geology》1993,22(4):353-361
Bellechester, Minnesota, is a small community of approximately 155 residents located on the county line between Goodhue and Wabasha counties in southeast Minnesota's karst region. Bellechester is served by a 21-year-old wastewater treatment facility (WWTF) consisting of three waste-stabilization ponds. On 28 April 1992 six sinkholes were discovered to have drained cell 2 of the WWTF resulting in the loss of approximately 8.7×106 1 of partially treated effluent and about 600 m3 of soil into previously undetected subsurface voids of unknown dimensions. In the week following the collapse, approximately 200 water wells located within a 5-km radius of the WWTF were sampled in an after-the-fact, emergency sampling program. Twelve samples with elevated fecal coliform levels, 18 samples with nitrate-nitrogen greater than the 10 mg/1 standard, and no samples with elevated chlorides were found. However, the elevated levels could not be unambiguously attributed to the WWTF collapse. This is the third WWTF to fail by sinkhole collapse in southeast Minnesota since 1974. All three collapsed lagoons have been located in similar geomorphic and stratigraphic settings. However, at least two lagoons have collapsed in the adjacent area in northeast Iowa, and these lagoons are located at different stratigraphic positions. Twenty-two WWTFs constructed in southeast Minnesota's karst region in the last 25 years have been identified as subject to potential sinkhole collapse. An unknown but significant number of manure storage lagoons, flood control structures, etc., have also been constructed in the karst region and are at risk. Public agencies are beginning to develop plans to deal with the risk associated with existing and future waste lagoons in this environment. The critical hydrogeologic parameters that can be used to prioritize the risk of collapse at existing facilities include: (1) the lithology of the first bedrock beneath each lagoon, (2) the thickness of surficial materials between the lagoon and the bedrock surface, (3) the presence and construction of liners (seepage rate), and (4) the proximity to existing sinkholes. 相似文献
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岩石密度和超高压岩石折返速率 总被引：1，自引：3，他引：1
在常温常压条件下对中国大陆科学钻CCSD主孔100-3000米岩心样品进行了密度测量,建立了密度连续剖面,并界定了不同超高压岩石的密度值。通过对比高温高压物性实验资料,岩石密度随着退变程度增强而降低,榴辉岩密度变化序列为3.52g/cm3→3.49g/cm3→3.07g/cm3→2.93g/cm3。超高压长英质岩石密度变化序列为3.00g/cm→2.80g/cm3→2.65g/cm3。上述实验资料是讨论不同折返阶段岩石所受浮力的基础,为研究折返速率大小提供了基本参数。本文通过折返板块运动平衡时,上浮力与粘滞力平衡这一关系式,定量研究了大陆俯冲板块的折返速率,认为密度差产生上浮力从而引起折返,温度对板块折返速率的影响最为显著;密度差大小、折返角度、折返板块大小对折返速率也有直接的影响。定量模拟分析表明,在温度高于850℃时,板块的折返速率可以超过100mm/a;当温度降至700℃时,折返速率则低于1.5mm/a。作者认为在折返早期,温度较高,板块快速折返至60-70km榴辉岩相深度;随着传导散热,温度降低,板块以较慢的速率折返至中下地壳。折返速率的估算表明,浮力是板块折返第一阶段(从>100km深部折返至<40km的中下地壳)的主要驱动力。 相似文献
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滇东南锡、银、铅、锌多金属矿床主要分布在个旧、白牛厂、都龙3个矿区,而滇东南较大的3个花岗岩体又分别出露在3个矿区或附近.花岗岩体均形成于燕山晚期,岩石化学、矿物成分相似,富含锡、银、铅、锌、钨、铜等成矿元素.矿床主金属元素组合与岩体之间的距离由远而近出现由锡、钨、(铍、铌、钽)→锡、钨、(铁)、铜、铟→锡、铅、锌、银、铟、(锑)有规律的变化.花岗岩浆是成矿物质来源和成矿热源.岩浆侵入初期使上覆地层隆起产生背斜(凹陷部位成向斜);同时使地层产生一系列裂隙、压性断层或层间断裂;岩浆侵入晚期,这些断层再次活动,表现为张性,岩浆产生的含矿热液沿由其活动所造成的断裂迁移、充填、交代、沉淀而形成矿床. 相似文献