岩石学报  2012, Vol. 28 Issue (12): 4031-4046   PDF    
东秦岭花山复式岩基中蒿坪与金山庙花岗岩体岩石地球化学、锆石U-Pb年代学和Lu-Hf同位素组成
肖娥1,2, 胡建1,2, 张遵忠1,2, 戴宝章1, 王艳芬2, 李海勇2     
1. 南京大学内生金属矿床成矿机制研究国家重点实验室,南京 210093;
2. 江苏省有色金属华东地质勘查局,南京 210007
摘要: 蒿坪与金山庙花岗岩体位于华北陆块南缘,是熊耳山地区花山复式岩基的重要组成部分。锆石LA-ICP-MS U-Pb定年显示,蒿坪岩体两个样品年龄为128.7±1.0Ma和129.3±2.4Ma,金山庙岩体一个样品年龄为127.6±1.6Ma,均为早白垩世岩浆作用的产物。蒿坪岩体以发育碱性长石大斑晶为主要特征,主要组成矿物为碱性长石、斜长石、石英、黑云母和少量角闪石等,而金山庙岩体矿物组合则为碱性长石、斜长石、石英和黑云母。化学组成上二岩体均具高硅准铝、富碱高钾及富铁贫镁的特征,轻重稀土元素分馏显著,Eu异常较弱或无明显Eu异常,Eu/Eu*为0.69~1.26,富集Cs、Rb、Ba、Sr等大离子亲石元素,亏损Nb、Ta、Ti、Y等高场强元素,在成因类型上可归为I型花岗岩,其中金山庙岩体经历了更高程度的分离结晶作用(D.I.=96.6~97.3),应属高分异I型花岗岩。锆石Lu-Hf同位素分析结果显示,蒿坪岩体εHf(t) 为-10.2~-13.3,tDM2为1.8 Ga~2.0 Ga,金山庙岩体εHf(t) 为-13.3~-17.5,tDM2为2.0~2.2Ga,表明二者的源区很可能是遭受了幔源或新生地壳改造的太华群古老基底物质。根据区域地质和全岩地球化学组成及产出动力地质背景的全面分析,表明蒿坪与金山庙岩体应形成于扬子陆块与华北陆块碰撞造山后的陆内伸展引张环境,是古特提斯构造域向古太平洋构造域转换体制下岩浆作用的产物。在成岩过程中,蒿坪和金山庙岩浆体系释放出大量富挥发组分(如F, Cl) 的热液流体(特别是高分异的金山庙岩体),萃取富集了围岩中的成矿物质或是叠加改造了先期(印支期或燕山早期) 形成的金矿床,使之运移至构造交汇部位规模性成矿。
关键词: 年代学     岩石地球化学     Lu-Hf同位素     金成矿效应     花山复式岩基     东秦岭    
Petrogeochemistry, zircon U-Pb dating and Lu-Hf isotopic compositions of the Haoping and Jinshanmiao granites from the Huashan complex batholith in eastern Qinling Orogen
XIAO E1,2, HU Jian1,2, ZHANG ZunZhong1,2, DAI BaoZhang1, WANG YanFen2, LI HaiYong2     
1. State Key Laboratory for Mineral Deposits Research, Nanjing University, Nanjing 210093, China;
2. East China Mineral Exploration and Development Bureau for Non-Ferrous, Nanjing 210007, China
Abstract: The Haoping and Jinshanmiao granitic plutons occurred in the southern margin of the North China Craton, are the important components of the Huashan complex batholith in Xiong'ershan region. Zircon LA-ICP-MS U-Pb dating yields ages of 128.7±1.0Ma to 129.3±2.4Ma for Haoping pluton, and of 127.6±1.6Ma for Jinshanmiao pluton, suggesting that they were all formed in Early Cretaceous. The Haoping pluton consists of alkali-feldspar, plagioclase, quartz, biotite and minor amphibole, and is mainly characterized by development of megaphyric alkali-feldspar, whereas the mineral assemblages of the Jinshanmiao pluton are alkali-feldspar, plagioclase, quartz and biotite. Chemically, these two plutons are both metaluminous, and characterized by rich in silicon and alkaline, poor in magnesium, and have high FeOT/(FeOT+MgO) ratios. These rocks are all enriched in Cs, Rb, Ba and Sr, etc., and depleted in Nb, Ta, Ti and Y, etc., and display a significant fractionation between LREEs and HREEs, with weakly negative Eu anomalies or no Eu anomalies (Eu/Eu*=0.69~1.26). Therefore, the Haoping and Jinshanmiao plutons could be grouped into I-type granites, and the latter should be further categorized to the highly fractionated granites due to the higher degree of differentiation (D.I.=96.6~97.3). The Lu-Hf isotopes shows that the εHf(t) values of the Haoping pluton range from -10.2 to -13.3, with tDM2 ages between 1.8Ga and 2.0Ga, while the εHf(t) values of the Jinshanmiao range from -13.3 to -17.5, with the tDM2 ages of 2.0Ga to 2.2Ga, indicating that these two plutons might be derived from the ancient materials of Taihua Group basement which was reformed by the mantle or the juvenile crust during the long-time geological evolvement. Integration of regional geology, whole-rock geochemistry and geodynamic considerations suggests that the Haoping and Jinshanmiao plutons should be emplaced in the intracontinental extensional environment followed by the end of the collision between the Yangtze and the North China blocks, which implies that they were formed during the tectonic transition from the Paleo-Tethys subduction-collision system to the Paleo-Pacific regime. During this diagenetic process, large amount of hydrothermal fluids with abundant volatile components (e.g., F, Cl) derived from the Haoping and Jinshanmiao magmatic systems, extracted and gathered the metallogenic materials from the country rocks, or superimposed and reformed the preexisting (Indosinian or Early Yanshanian) gold deposits, and then transported them to the intersection of many tectonic systems and formed large scale mineralization.
Key words: Chronology     Petrogeochemistry     Lu-Hf isotopes     Gold mineralization     Huashan complex batholith     Eastern Qinling Orogen    

华北陆块南缘作为秦岭造山带现今三维结构的基本要素和重要组成部分,在其漫长的地质演化过程中,历经克拉通形成、古陆增生,陆陆碰撞及陆内构造演化等多个阶段(陈衍景和富士谷,1992)。复杂的构造演化和普遍发育的岩浆活动使得该区成为我国著名的金矿集中区之一,小秦岭、祁雨沟、上宫、青岗坪、干树凹、康山、瑶沟、前河、虎沟、小池沟等10多个大、中型金矿蕴涵其间,前人对区内金矿的矿床地质、矿床成因等方面开展了大量卓有成效的研究(Mao et al., 2002Chen et al., 2006, 2008, 2009Fan et al., 2011Zhao et al., 2011a, b, 2012a; 胡受奚和林潜龙,1988胡受奚等,1998陈衍景和富士谷,1992任富根等,1999范宏瑞等, 1998, 2000卢欣祥等, 2003, 2004李永峰等, 2004, 2005郭东升等,2007李诺等,2008姚军明等,2009周振菊等,2011),但对该区与成矿关系密切的花岗岩研究较少,特别是对其岩石成因类型及岩浆源区缺乏详细阐述。为此,本次研究选取华北陆块南缘熊耳山地区与早白垩世金成矿具有密切时空联系的典型花岗岩--金山庙和蒿坪岩体作为研究对象,对其进行成岩年代学、元素地球化学及Lu-Hf同位素详细研究,阐明岩体的成因类型归属,构建岩浆的成因演化模式,并在综合分析该区地质演化背景的基础上,探讨岩浆活动对区内金矿床富集成矿存在的可能制约。

1 岩体地质与岩相学特征

花山复式花岗岩基位于华北陆块南缘熊耳山地区,主要由晚侏罗世五丈山岩体、早白垩世蒿坪及金山庙岩体等组成(图 1)。

图 1 东秦岭花山复式岩基地质简图 ①三门-铁炉坪断裂;②康山-七里坪断裂;③红庄-青岗坪断裂;④陶村-马园断裂 Fig. 1 Sketch map showing the regional geology of the Huashan complex batholith in eastern Qinling orogen ①Sanmen-Tieluping fault; ②Kangshan-Qiliping fault; ③Hongzhuang-Qinggangping fault; ④Taocun-Mayuan fault

蒿坪岩体呈北东转东西向的弧形分布于熊耳山隆起的轴部,围岩为新太古代-古元古代太华群(图 1b)。主要岩性有似斑状黑云母二长花岗岩、似斑状黑云角闪二长花岗岩等,以含粗大的碱性长石斑晶为特征。斑晶约占岩石总体积的15%~20%,为肉红色(少数灰白色),自形-半自形,颗粒多在5×10mm~10×25mm之间,少数可达到10×45mm,其种属为条纹长石,内部常见斜长石、角闪石、黑云母、石英等其他矿物包裹体(图 2b)。基质则由更-中长石(~30%,An=20~40,聚片双晶和环带构造发育)、碱性长石(10%~15%,条纹长石和微斜条纹长石)、石英(25%~30%) 等组成。暗色矿物主要有黑云母(3~5%) 和角闪石(2%~3%) 等。副矿物普遍发育且富集,主要有榍石、磷灰石、锆石、钛磁铁矿等(图 2ab)。

图 2 蒿坪与金山庙岩体岩相学特征 (a、b)-蒿坪岩体;(c、d)-金山庙岩体.Per-条纹长石;Pl-斜长石;Mc-微斜长石;Qtz-石英;Bt-黑云母;Amp-角闪石;Spn-榍石;Ap-磷灰石.均为正交偏光 Fig. 2 Petrographical characteristics of the Haoping and Jinshanmiao plutons (a, b)-Haoping pluton; (c, d)-Jinshanmiao pluton. Per-perthite; Pl-plagioclase; Mc-microcline; Qtz-quartz; Bt-biotite; Amp-amphibole; Spn-sphene; Ap-apatite. All microphotos are taken under crossed nicols

金山庙岩体位于花山复式岩基北端,主要侵入于新太古代-古元古代太华群及早期蒿坪岩体中,局部被第四纪沉积物覆盖(图 1b)。岩体岩性主要为中粗粒黑云母花岗岩、中粗粒黑云二长花岗岩等,组成矿物有碱性长石(35%~40%)、斜长石(25%~30%)、石英(30%) 和黑云母(3%~5%) 等(图 2cd),其中碱性长石主要为微斜长石或微斜条纹长石,可见格子双晶和条纹构造。斜长石普遍发育聚片双晶,亦可见环带构造,An=15~32,属更-中长石。暗色矿物主要为黑云母,角闪石少见。副矿物则有锆石、磷灰石、榍石、钛磁铁矿等。

2 样品与分析方法

全岩样品经破碎、淘洗、磁选及重液分离后,筛选出锆石精样,然后在双目镜下挑选表面平整光洁且具不同长宽比例、不同柱锥面特征的锆石颗粒,将之用环氧树脂固结,后抛光至锆石核部出露以待测试。锆石U-Pb定年之前,先在南京大学内生金属矿床成矿机制研究国家重点实验室采用配有Gatan Mono CL的JEOL JXA-8100电子探针显微分析仪对抛光后的锆石样品进行阴极发光(CL) 图像拍摄,以了解被测锆石的内部结构,并作为锆石年龄及Hf同位素测试选点的依据。实验过程中工作电压15kV,电流20nA。

锆石LA-ICP-MS U-Pb定年工作在南京大学内生金属矿床成矿机制研究国家重点实验室使用New Wave 213nm激光取样系统与Agi1ent 7500s ICP-MS联机装置完成。在分析过程中以He作为剥蚀物质的载气,激光束斑直径为21μm,频率为5Hz。每个测试流程的开头和结尾分别测2个GJ (207Pb/206Pb年龄608.5±1.5Ma, Jackson et al., 2004) 标样,另外测试1个MT (732±5Ma,Black and Gulson, 1978) 标样和10个待测样品点。详细的分析方法和流程类似于Griffin et al. (2004)Jackson et al. (2004)。普通铅校正使用嵌入Excel的ComPbCorr#3_15G程序(Andersen, 2002) 进行。年龄及谐和图绘制采用Isoplot程序(ver2.49, Ludwig, 2001)。

全岩地球化学分析样品先经岩相学观察与鉴定,以选出新鲜样品,然后细碎至200目以上。主量元素在南京大学现代分析中心采用瑞士生产的ARL9800XP+型X射线荧光光谱仪测定,使用Li2B4O7和LiBO2(67:33) 混合熔剂与加拿大Glaisse高温自动燃气熔样机制样,测试条件为:X射线工作电压40kV,电流60mA,分析精度优于5%;微量元素(包括稀土元素) 在中国科学院地球化学研究所环境地球化学国家重点实验室采用美国PerkinElmer公司制造的四级杆电感耦合等离子体质谱(Q-ICP-MS,型号为ELAN DRC-e) 分析,相对标准偏差优于10%。

锆石LA-MC-ICP-MS Lu-Hf同位素测试在中国科学院地球化学研究所环境地球化学国家重点实验室完成。锆石熔样用New Wave Research生产的UP-213型(λ=213nm) Nd:YAG激光器进行,分析时以He作为剥蚀物质的载气,采用10Hz的激光频率和60μm的激光束斑直径。仪器的运行条件及详细的分析流程见唐红峰等(2008)。测试过程中标准锆石91500的176Hf/177Hf分析结果为0.282310±27(2σ, n=26),与推荐值(0.282302±8, Goolaerts et al., 2004) 在误差范围内一致。

3 锆石U-Pb年代学

金山庙岩体锆石多呈长柱状,无色透明,自形性较好,长径约80~150μm,其阴极发光(CL) 图像显示清晰的震荡环带结构(图 3a),Th/U比值变化于0.77~2.50(表 1),具典型岩浆锆石高Th/U比值特征(Wu and Zheng, 2004)。对18个锆石测试点定年,获得206Pb/238U表面年龄变化于123~134Ma (表 1),在207Pb/235U-206Pb/238U谐和图上,所有测试点均投影在谐和线上或谐和线附近(图 4a),变化幅度较小,表明被测锆石未遭受明显的后期热事件影响,其206Pb/238U加权平均年龄为127.6±1.6Ma (MSWD=2.5,2σ),可代表岩体的结晶年龄。

图 3 金山庙(a) 与蒿坪岩体(b、c) 锆石阴极发光(CL) 图像 Fig. 3 CL images of zircons from the Jinshanmiao (a) and Haoping (b, c) plutons

图 4 金山庙与蒿坪岩体锆石U-Pb年龄谐和图 Fig. 4 Zircon U-Pb concordia diagrams for the Jinshanmiao and Haoping plutons

表 1 金山庙岩体及蒿坪岩体锆石LA-ICP-MS U-Pb测试结果 Table 1 Zircon LA-ICP-MS U-Pb dating for the Jinshanmiao and Haoping plutons

蒿坪岩体西段(HP-1) 锆石多呈自形晶且无色透明,粒径较大,长约100~350μm。本次测试获得16个锆石点的Th/U比值变化于0.82~1.54,结合CL图像显示清晰震荡环带(图 3b),表明这些锆石具有显著的岩浆成因特征。在207Pb/235U-206Pb/238U谐和图上,所有测试点均投影在谐和线上或谐和线附近(图 4b),通过加权平均计算,获得206Pb/238U年龄为128.7±1.0Ma (MSWD=1.1,2σ)。蒿坪岩体东段(HP-4) 被测锆石多呈柱状或长柱状,少数为短柱状、磨圆状,无色透明(图 3c)。定年结果显示,在16组有效数据中,13个锆石测试点的206Pb/238U表面年龄集中在123~136Ma,其加权平均年龄为129.3±2.4Ma (MSWD=4.0,2σ),与蒿坪岩体西段定年结果相一致,可代表蒿坪岩体的成岩年龄。测试中,还获得3组古老的继承锆石年龄(HP4-08:2253±26Ma;HP4-17:2151±24Ma;HP4-19:2128±24 Ma),在207Pb/235U-206Pb/238U谐和图上(图 4d),所有16组测试点构成的不一致线与谐和线相交,获得上交点年龄为2268±56Ma,与Xu et al.(2009)第五春荣等(2007)测得的太华群年龄基本一致,表明本区中生代花岗质岩浆的产出很可能与古老的太华群基底物质有密切的成因联系。

定年结果表明,金山庙岩体与蒿坪岩体均形成于早白垩世中期,成岩年龄变化于127.6~129.3Ma之间,表明二者应为同一构造-岩浆事件的产物,这与毛景文等(2005)利用锆石SHRIMP U-Pb方法对花山岩体研究所获得的结果(130.7±1.4Ma) 在误差范围内吻合。

4 元素地球化学

蒿坪与金山庙岩体的主量、微量及稀土元素分析结果列于表 2。由表中数据可以看出,二岩体总体上具有相似的主量元素组成特征,如高硅准铝(图 5a;蒿坪岩体:SiO2=66.74%~71.75%,A/CNK=0.91~0.95;金山庙岩体:SiO2=71.56%~75.04%,A/CNK=0.97~0.99)、富碱高钾(图 5b;蒿坪岩体:ALK=8.92~9.74,K2O/Na2O=1.24~1.30,A.R=2.55~3.54;金山庙岩体:ALK=8.92~9.74,K2O/Na2O=0.95~1.46,A.R=3.36~3.40)、富铁贫镁(蒿坪岩体:FeOT/(FeOT+MgO)=0.79~0.81;金山庙岩体:FeOT/(FeOT+MgO)=0.71~0.81) 等,可与世界I型花岗岩对比,明显区别于典型的S型花岗岩,后者往往具有强过铝特征(A/CNK>1.1,Chappell and White, 1974),但蒿坪与金山庙岩体在分异程度上仍有差别,前者分异指数(D.I.) 变化于91.6~95.1,而后者则为96.6~97.3,二岩体样品点在SiO2-P2O5相关图上(图 6a) 表现出明显的负消长演化关系,且金山庙岩体位于分异演化的末端,表明后者经历了更高程度的分异演化。

图 5 蒿坪与金山庙岩体A/CNK-A/NK (a,据Maniar and Piccolli, 1989) 及A.R-SiO2(b,据Wright, 1969) 关系图 图 6图 9-图 11图例同此图 Fig. 5 A/CNK-A/NK (a, after Maniar and Piccolli, 1989) and A.R-SiO2(b, Wright, 1969) diagrams for the Haoping and Jinshanmiao plutons The symbols in Fig. 6, Fig. 9-Fig. 11 are the same as those in this figure

图 6 蒿坪与金山庙岩体SiO2-P2O5(a) 和SiO2-Pb (b) 关系图解(据Chappell and White, 1992) Fig. 6 SiO2-P2O5(a) and SiO2-Pb (b) diagrams of the Haoping and Jinshanmiao plutons (after Chappell and White, 1992)

表 2 蒿坪与金山庙岩体的化学组成及主要地球化学参数(主量元素:wt%;稀土和微量元素:×10-6) Table 2 Chemical compositions and major geochemical parameters of the Haoping and Jinshanmiao plutons (Major elements: wt%; Trace elements: ×10-6)

从微量元素蛛网图上可以看出,蒿坪与金山庙岩体均富集Rb、Ba、K、Sr等大离子亲石元素元素,亏损Nb、Ta、Ti、Y等高场强元素,表现出明显的壳源特征(图 7a)。在稀土元素组成上(表 2图 7b),蒿坪与金山庙岩体均显示右倾的稀土配分模式,Eu异常较弱或无明显Eu异常,轻稀土的分馏程度较高,(La/Sm)N=4.89~9.88,而重稀土分馏则相对不显著,(Gd/Yb)N=1.38~2.56,这些特征与太华群地层岩石稀土配分模式几近相同,表明蒿坪与金山庙岩体在物质源区方面很可能与太华群地层有着紧密的亲缘关系。相比较而言,金山庙岩体较蒿坪岩体具有更高的稀土总量,金山庙岩体∑REE变化于153.7×10-6~211.7×10-6,而蒿坪岩体∑REE则变化于100.7×10-6~157.5×10-6,此外,二者轻重稀土分馏程度也明显有别,金山庙岩体LREE/HREE变化于22.77~27.18,(La/Yb)N=33.85~37.20,而蒿坪岩体分馏程度明显偏低,LREE/HREE=12.68~17.90,(La/Yb)N=13.96~27.27,表明前者较后者经历了更高程度的分离结晶作用。

图 7 蒿坪与金山庙岩体微量元素原始地幔标准化蛛网图(a, 标准化值据McDonough and Sun, 1995) 及稀土球粒陨石标准化配分曲线(b, 标准化值据Boynton, 1984) 图中阴影部分资料据第五春荣等(2007) Fig. 7 Primitive mantle-normalized spidergrams (a, normalization values after McDonough and Sun, 1995) and chondrite normalized REE distribution patterns (b, normalization values after Boynton, 1984) for the Haoping and Jinshanmiao plutons The data of shaded parts are after Diwu et al. (2007)
5 Hf同位素组成

表 3列出了蒿坪(HP-1) 和金山庙(JSM-3) 岩体锆石Lu-Hf同位素组成及其相关计算参数。从中可以看出,除蒿坪岩体个别锆石测试点176Lu/177Hf比值稍大外,其余所有测试点的176Lu/177Hf比值均小于0.002,表明锆石在岩体形成之后漫长的演化历程中,由176Lu衰变生成的176Hf极少,因而可以利用锆石176Hf/177Hf比值探索岩体形成时的成因信息(Patchett et al., 1981Knudsen et al., 2001Kinny and Mass, 2003Zhao et al., 2010, 2012b; Yang et al., 2011吴福元等, 2007)。

表 3 蒿坪与金山庙岩体锆石Lu-Hf同位素分析结果 Table 3 Zircon Lu-Hf isotopic compositions of the Haoping and Jinshanmiao plutons

蒿坪岩体锆石176Hf/177Hf比值较为均一,主要变化于0.282322~0.282406(图 8b),相应的εHf(t=128.7Ma) 值变化范围在-13.3~-10.2之间,加权平均值为-11.6。金山庙岩体锆石176Hf/177Hf比值同样比较均一,但较蒿坪岩体稍小,主要在0.282202~0.282319之间变化,εHf(t=127.6Ma) 值变化于-13.3~-17.5,加权平均值为-16.0。考虑到上述二岩体均具较低fLu/Hf比值(平均值为-0.96),因此二阶段模式年龄更能真实得反映其源区物质在地壳的居留时间(Amelin et al., 2000Vervoort et al., 1996Yang et al., 2010吴福元等, 2007)。蒿坪和金山庙岩体tDM2平均值分别为1910Ma和2187Ma,说明它们的物质来源很可能与新太古代-古元古代地壳基底物质有着密切的联系,同时也不排除古老的地壳组分遭受了幔源或新生地壳物质的改造。在测试过程中,蒿坪和金山庙岩体各获得一组继承锆石Lu-Hf同位素数据,其176Hf/177Hf比值分别为0.281320和0.281279,与第五春荣等(2007)对豫西宜阳TTG质片麻岩测试结果基本一致,表明太华群很可能是蒿坪和金山庙岩体重要的物源组分之一。

图 8 蒿坪(a) 与金山庙(b) 岩体锆石Hf同位素组成 Fig. 8 Zircon Hf isotopic compositions of the Haoping (a) and Jinshanmiao (b) plutons
6 讨论 6.1 岩石成因类型

在东秦岭地区,燕山期花岗岩广泛发育,有学者将这些花岗岩归为改造型系列(胡受奚和林潜龙,1988胡志宏和胡受奚,1990),但也有学者认为这些花岗岩是在俯冲-挤压环境下,由新太古界基底物质发生部分熔融形成,应归属为陆内同熔型花岗岩,亦即I型花岗岩(范宏瑞等, 1994毕献武和骆庭川, 1995)。前述地球化学特征显示,蒿坪和金山庙岩体均具高硅、准铝、富碱和高钾的特征,在SiO2-P2O5及SiO2-Pb图解上(图 6ab),二岩体投影点变化趋势与I型花岗岩一致,明显区别于S型花岗岩,后者在演化过程中P2O5含量往往具有递增的趋势,而Pb含量则逐渐减少(Chappell and White, 1992)。此外,蒿坪和金山庙岩体轻重稀土分馏异常显著,配分型式呈明显的右倾斜形,这也与S型花岗岩常表现出的“海鸥型”稀土配分型式明显不同。锆石饱和温度(Watson and Harrison, 1983) 计算结果表明,蒿坪和金山庙岩体温度变化于718~777℃(表 2),较低的成岩温度不支持它们为A型花岗岩,后者的锆石饱和温度往往在800℃以上(King et al., 1997Yang et al., 2012刘昌实等, 2003)。尽管金山庙岩体Ga/Al比值较高,变化于3.19~3.27(表 2),与A型花岗岩Ga/Al比值变化一致,但在高分异的岩浆体系中,Ga元素易与挥发组分结合进入熔体相,因而高分异岩体同样具有偏高的Ga/Al比值(刘昌实等, 2003)。在高场强元素对主要氧化物比值及Ga/Al比值判别图解上(图 9),上述二岩体均投影在非A型花岗岩区域,其中蒿坪岩体主要投影在正常花岗岩区(OGT),而金山庙岩体则投影在分异花岗岩区(FG)。因此,蒿坪和金山庙岩体均应为I型花岗岩,其中金山庙岩体分异程度更高,可归属为高分异的I型花岗岩范畴。

图 9 蒿坪与金山庙岩体Zr+Nb+Ce+Y对FeOT/MgO、(K2O+Na2O)/CaO及10000×Ga/Al图解(a, b据Whalen et al., 1987; c, 据Eby, 1990) Fig. 9 Zr+Nb+Ce+Y vs. FeOT/MgO, (K2O+Na2O)/CaO and 10000×Ga/Al diagrams of the Haoping and Jinshanmiao plutons (a, b, after Whalen et al., 1987; c, after Eby, 1990)
6.2 岩浆源区及成岩过程

蒿坪和金山庙岩体在空间上紧邻并近于同期形成,且二者地球化学变化特征相似,表明二者应具有相似的物质源区。前述Hf同位素特征显示,蒿坪和金山庙岩体均具有较低的εHf(t) 值,在εHf(t)-t图上(图 10),多数样品分布于球粒陨石及地壳分异演化线之间,但二岩体亦有差别,金山庙岩体εHf(t) 值较蒿坪岩体更小,表明金山庙岩体在成岩过程中可能卷入了较多量的地壳物质。毕献武和骆庭川(1995)研究认为,花山复式岩基(包括金山庙和蒿坪岩体) 主体侵入于太华群地层中,其Sr同位素初始比值为0.7078,接近于太华群地层岩石的Sr初始比值(ISr=0.7060),而明显区别于熊耳群Sr初始比值(ISr=0.7125~0.7141)。范宏瑞等(1994)也认为花山复式岩基是燕山期华北陆块南缘发生的陆内挤压-俯冲作用的产物,由太华群变质岩经重熔作用形成。蒿坪和金山庙岩体中均发现有太华群继承锆石存在,且二岩体的稀土配分曲线与太华群地层近似,暗示这二岩体的物质源区应与太华群有着紧密的亲缘关系。然而,蒿坪和金山庙锆石二阶段Hf模式年龄较太华群TTG质变质岩石同位素年龄明显年轻(Xu et al., 2009第五春荣等, 2007),显然太华群不可能单独作为这些花岗岩的物质源区。因此,蒿坪和金山庙岩体在成岩过程中很可能有幔源或新生地壳组分加入,或是其源区在漫长的地质演化过程中遭受(一次或多次) 过新生物质的混染和改造。

图 10 蒿坪与金山庙岩体的εHf(t)-t图解 Fig. 10 εHf(t)-t diagram of the Haoping and Jinshanmiao plutons

岩相学特征显示,蒿坪岩体碱性长石(条纹长石或微斜条纹长石) 斑晶十分发育。这些(大) 斑晶的形成主要取决于晶体成核密度与生长速度之间的动态相互作用(Swanson, 1977Cashman and Marsh, 1988仲卫国等, 2005)。当成核密度大,晶体生长速度慢时,较易形成细粒结构、隐晶质结构或玻璃质结构,而当成核密度小,晶体生长速度快时,则易形成粗晶或巨晶。根据Swanson (1977)人工合成花岗质岩浆体系实验资料,蒿坪岩体原始熔浆温度应大于950℃,冷却至900~800℃时,碱性长石(大) 斑晶开始快速生长,因为在岩浆温度降至800℃之前,碱性长石的生长速度一直大于其成核速度。由此可以推测蒿坪岩体由于岩浆房体积较大,热量不易散失,故能在相当长的一段时间内维持较高的热场环境,使得岩浆冷却速度变慢,碱性长石晶体得以快速生长,成长为巨大的斑晶。与之对比,金山庙岩体由于岩浆房体积较小,热量容易散失,使得过冷度增大,因而在晶体生长过程中未生成碱性长石(大) 斑晶。

综上所述,蒿坪与金山庙岩体的形成很可能经历了二个阶段的成岩过程:首先太华群基底物质遭受了幔源或新生地壳物质的改造,至早白垩世时,这些被改造的源区物质发生部分熔融并经不同岩浆通道上升侵位,在此过程中,由于岩浆通道及岩浆房容纳的岩浆体积不一,导致原始岩浆在上升侵位过程中仍可能遭受地壳物质的混染而使岩浆的局部性状发生改变。金山庙岩体由于体积小、演化程度高,在上升侵位过程中更易受围岩物质的影响,因而其εHf(t) 值较蒿坪岩体稍低。

6.3 构造环境与成矿

中生代是秦岭造山带构造体制发生转换的关键时期,受古特提斯构造域和古太平洋构造域构造动力此弱彼强的影响,中国大陆中东部区域构造体系由印支期以近东西向为主逐渐向燕山期北东-北北东向转变(任纪舜等, 1992张国伟等, 2001)。在此期间,深部地幔动力学机制一直处于平衡调整状态,地幔和地壳之间发生强烈的物源和热源传输交换,导致原形成于主造山期的碰撞造山格局遭受破坏和改造(Meng and Zhang, 2000张国伟等, 1997, 2001, 2003),软流圈物质上涌并底侵诱发加厚的下地壳物质发生部分熔融形成中酸性岩浆,沿构造薄弱带上升到浅部侵位形成花岗岩(朱赖民等,2008)。在R1-R2及Rb-(Y+Nb) 构造判别图上(图 11),形成于早白垩世的蒿坪和金山庙岩体多数样品均落入后碰撞或造山晚期花岗岩区域,表明二岩体应形成于华北陆块与扬子陆块碰撞造山后陆内伸展的地球动力学背景(Meng and Zhang, 2000张国伟等,2001; 王义天和毛景文, 2002; 戴宝章等,2009)。

图 11 蒿坪与金山庙岩体构造环境判别图(a, 据Batchelor and Bowden, 1985;b, 据Pearce, 1996) Fig. 11 Tectonic discrimination diagrams of the Haoping and Jinshanmiao plutons (a, after Batchelor and Bowden, 1985; b, after Pearce, 1996)

东秦岭熊耳山和小秦岭地区是我国最主要的金矿产地之一(Fan et al., 2011Zhao et al., 2011a, 2012a卢欣祥等, 2004李厚民等, 2007蒋少涌等, 2009),区内金矿床的发育具有多期次、多类型成因特征(陈衍景等, 1992, 2003朱嘉伟等, 1999徐启东等, 1998王义天等, 2001李厚民等, 2007李诺等, 2008蒋少涌等, 2009周振菊等, 2011),且与花岗岩在时空分布、岩石成因和产出构造背景方面有着广泛的联系(胡受奚等,1998王义天和毛景文,2002胡海珠和李毅,2006)。本次研究获知蒿坪和金山庙岩体均为早白垩世构造-岩浆作用的产物,其锆石LA-ICP-MS U-Pb年龄分别为127.6±1.6Ma以及128.7±1.0Ma和129.3±2.4Ma,与熊耳山地区上宫、瑶沟、崤山以及祁雨沟等金矿成矿年龄相仿(陈衍景和富士谷, 1992朱嘉伟等, 1999王义天等, 2001),表明金矿床的形成很可能直接或间接受控于同期且同构造体系下产出的花岗质岩浆。从空间分布来看,熊耳山地区金矿床几乎都产于花山复式岩基的两侧或附近,且矿体的赋存受东西和北东向双重构造体系的控制(图 1a),表明这些金矿床的产出不但与古特提斯构造域有关,同时也受到古太平洋构造域的严格制约。在构造体制大转换背景下,加厚的下地壳发生部分熔融形成大量花岗质岩浆,随着分异演化程度的增加,往往伴随有大量富含挥发组分(如F, Cl) 的流体析出,这些结晶最晚阶段的热液流体对迁移和富集来自岩浆或其围岩体系中的成矿物质具有十分重要的作用(Webster and Holloway, 1990张德会等, 2001芮宗瑶等, 2003)。研究表明,金在成矿流体中主要呈络合物、胶体或被有机质吸附等多种形式迁移,其中以Au-Cl络合物、Au-S络合物两种形式较为普遍,且在高温条件下又以Au-Cl络合物最为稳定(卢欣祥等,2004)。刘英俊和马东升(1991)认为金矿的定位可能与对其提供热源和矿化剂的花岗岩体具有一定的距离,中酸性岩浆作用晚期发育的富氯热液具有明显向岩体外部或外围迁移而形成有关的热液蚀变和矿化的趋势,从而引起金在岩体边缘和外接触带形成富集。蒿坪和金山庙岩体分异程度较高,尤其是金山庙岩体,属高分异的I型花岗岩,这些花岗质岩浆在漫长的分异演化过程中,伴生有大量深源流体并向浅部运移,破坏改造先期(印支期或燕山早期) 形成的金矿床或萃取富集围岩中的成矿物质。陈衍景等(1992)研究发现,小秦岭和熊耳山地区与金矿有关的花岗岩类总体上可分为两种:一是直接控制矿床产出的花岗岩类,与之有关的矿床主要为斑岩型、爆破角砾岩筒型以及矽卡岩型,如祁雨沟金矿、银家沟金矿等,统称为浆控系列金矿;另一种情况为花岗岩类间接控制金矿床的产出,即金矿分布于花岗岩的边缘或外接触带,以上宫、瑶沟、前河和青岗坪等金矿为典型代表。蒿坪和金山庙岩体明显属于后者,它们在金矿的成矿过程中提供了大量的矿化剂和热能,使成矿热液活化并进一步运移至岩体外侧断裂交汇部位进而富集成矿。

7 结论

(1) 锆石LA-ICP-MS U-Pb定年结果表明,蒿坪与金山庙岩体均形成于早白垩世中期,成岩年龄变化于127.6~129.3Ma之间,表明二者应为同一构造-岩浆事件的产物。

(2) 蒿坪和金山庙岩体均具高硅准铝、富碱高钾以及富铁贫镁的特征,且富集Rb、Ba、Sr、La、Ce等大离子亲石元素和轻稀土元素,亏损Nb、Ta、Ti、Y、Yb等高场强元素和重稀土元素,其岩石成因类型应为Ⅰ型花岗岩,其中,金山庙岩体经历了较高程度的分离结晶作用(D.I.=96.6~97.3),可归属为高分异Ⅰ型花岗岩。

(3) 锆石Lu-Hf同位素分析结果显示,蒿坪岩体εHf(t)=-10.2~-13.3,tDM2=1.8~2.0Ga,金山庙岩体εHf(t)=-13.3~-17.5,tDM2=2.0~2.2Ga,表明二者的源区为遭受了幔源或新生地壳改造的太华群古老基底物质,金山庙岩体εHf(t) 值较蒿坪岩体低很可能是因为在上升侵位过程中卷入了更多的地壳组分。

(4) 蒿坪与金山庙岩体形成于扬子陆块与华北陆块碰撞造山后的陆内伸展引张环境,是古特提斯构造域向古太平洋构造域转换机制下岩浆作用的产物。它们在形成过程中释放出大量的高温热液流体(特别是属高分异I型花岗岩的金山庙岩体),叠加、破坏并改造了先期(印支期或燕山早期) 形成的金矿床或是萃取富集了围岩中的成矿物质,使之运移至容矿部位形成规模性成矿。

致谢 实验过程中得到了中国科学院地球化学研究所唐红峰和漆亮研究员,南京大学内生金属矿床成矿机制研究国家重点实验室张文兰和武兵老师的大力帮助,在此表示衷心感谢。
参考文献
[] Amelin Y, Lee DC, Halliday AN. 2000. Early-middle archaean crustal evolution deduced from Lu-Hf and U-Pb isotopic studies of single zircon grains. Geochimica et Cosmochimica Acta, 64(24): 4205–4225. DOI:10.1016/S0016-7037(00)00493-2
[] Andersen T. 2002. Correction of common lead in U-Pb analyses that do not report 204Pb. Chemical Geology, 192(1-2): 59–79. DOI:10.1016/S0009-2541(02)00195-X
[] Batchelor RA, Bowden P. 1985. Petrogenetic interpretation of granitoid rock series using multicationic parameters. Chemical Geology, 48(1-4): 43–55. DOI:10.1016/0009-2541(85)90034-8
[] Bi XW, Luo TC. 1995. Geochemical characteristics and genesis of Huashan granite mass. Acta Mineralogica Sinica, 15(4): 433–441.
[] Black LP, Gulson BL. 1978. The age of the Mud Tank carbonatite, Strangways Range, Northern Territory, BMR. Journal of Australian Geology and Geophysics, 3: 227–232.
[] Blichert-Toft J, Albarède F. 1997. The Lu-Hf isotope geochemistry of chondrites and the evolution of the mantle-crust system. Earth and Planetary Science Letters, 148(1-2): 243–258. DOI:10.1016/S0012-821X(97)00040-X
[] Boynton WV. 1984. Geochemistry of the rare earth elements: Meteorite studies. In: Henderson P (ed.). Rare Earth Elements Geochemistry. Amsterdam: Elsevier, 63-144
[] Cashman KV, Marsh BD. 1988. Crystal size distribution (CSD) in rocks and the kinetics and dynamics of crystallization II: Makaopuhi lava lake. Contributions to Mineralogy and Petrology, 99(3): 292–305. DOI:10.1007/BF00375363
[] Chappell BW, White AJR. 1974. Two contrasting granite types. Pacific Geology, 8: 173–174.
[] Chappell BW, White AJR. 1992. I-and S-type granites in the Lachlan Fold Belt. Transactions of the Royal Society of Edinburgh: Earth Sciences, 83(1-2): 1–26. DOI:10.1017/S0263593300007720
[] Chen YJ, Fu SG. 1992. Gold Mineralization in West Henan, China. Beijing: Seismological Press.
[] Chen YJ, Fu SG, Hu SX. 1992. The metallogenic times of gold deposits in western Henan. Geological Exploration for Non-ferrous Metals, 1(3): 140–144.
[] Chen YJ, Sui YH, Pirajno F. 2003. Exclusive evidences for CMF model and a case of orogenic silver deposits: Isotope geochemistry of the Tieluping silver deposit, East Qinling orogen. Acta Petrologica Sinica, 19(3): 551–568.
[] Chen YJ, Pirajno F, Qi JP, Li J, Wang HH. 2006. Ore geology, fluid geochemistry and genesis of the Shanggong gold deposit, eastern Qinling Orogen, China. Resource Geology, 56(2): 99–116. DOI:10.1111/rge.2006.56.issue-2
[] Chen YJ, Pirajno F, Qi JP. 2008. The Shanggong gold deposit, eastern Qinling Orogen, China: Isotope geochemistry and implications for ore genesis. Journal of Asian Earth Sciences, 33(3-4): 252–266. DOI:10.1016/j.jseaes.2007.12.002
[] Chen YJ, Pirajno F, Li N, Guo DS, Lai Y. 2009. Isotope systematics and fluid inclusion studies of the Qiyugou breccia pipe-hosted gold deposit, Qinling orogen, Henan Province, China: Implications for ore genesis. Ore Geology Reviews, 35(2): 245–261. DOI:10.1016/j.oregeorev.2008.11.003
[] Dai BZ, Jiang SY, Wang XL. 2009. Petrogenesis of the granitic porphyry related to the giant molybdenum deposit in Donggou, Henan Province, China: Constraints from petrogeochemistry, zircon U-Pb chronology and Sr-Nd-Hf isotopes. Acta Petrologica Sinica, 25(11): 2887–2899.
[] Diwu CR, Sun Y, Lin CL, Liu XM, Wang HL. 2007. Zircon U-Pb ages and Hf isotopes and their geological significance of Yiyang TTG gneisses from Henan Province, China. Acta Petrologica Sinica, 23(2): 253–262.
[] Eby GN. 1990. The A-type granitoids: A review of their occurrence and chemical characteristics and speculations on their petrogenesis. Lithos, 26(1-2): 115–134. DOI:10.1016/0024-4937(90)90043-Z
[] Fan HR, Xie YH, Wang YL. 1994. Petrological and geochemical characteristics and genesis of the Huashan granitic batholith, western Henan. Acta Petrologica et Mineralogica, 13(1): 19–32.
[] Fan HR, Xie YH, Wang YL. 1998. Fluid-rock interaction during mineralization of the Shanggong structure-controlled alteration-type gold deposit in western Henan province, Central China. Acta Petrologica Sinica, 14(4): 529–541.
[] Fan HR, Xie YH, Zheng XZ, Wang YL. 2000. Ore-forming fluids in hydrothermal breccia-related gold mineralization in Qiyugou, Henan Province. Acta Petrologica Sinica, 16(4): 559–563.
[] Fan HR, Hu FF, Wild SA, Yang KF, Jin CW. 2011. The Qiyugou gold-bearing breccia pipes, Xiong'ershan region, Central China: Fluid-inclusion and stable-isotope evidence for an origin from magmatic fluids. International Geology Review, 53(1): 25–45. DOI:10.1080/00206810902875370
[] Goolaerts A, Mattielli N, de Jong J, Weis D, Scoates JS. 2004. Hf and Lu isotopic reference values for the zircon standard 91500 by MC-ICP-MS. Chemical Geology, 206(1-2): 1–9. DOI:10.1016/j.chemgeo.2004.01.008
[] Griffin WL, Wang X, Jackson SE, Pearson NJ, O'Reilly SY, Xu XS, Zhou XM. 2002. Zircon chemistry and magma mixing, SE China: In-situ analysis of Hf isotopes, Tonglu and Pingtan igneous complexes. Lithos, 61(3-4): 237–269. DOI:10.1016/S0024-4937(02)00082-8
[] Griffin WL, Belousova EA, Shee SR, Pearson NJ, O'Reilly SY. 2004. Archean crustal evolution in the northern Yilgarn Craton: U-Pb and Hf-isotope evidence from detrital zircons. Precambrian Research, 131: 231–282. DOI:10.1016/j.precamres.2003.12.011
[] Guo DS, Chen YJ, Qi JP. 2007. Isotope geochemistry and ore genesis of the Qiyugou gold deposit, Henan: A synthesis. Geological Review, 53(2): 217–227.
[] Hu HZ, Li Y. 2006. Magmatic activities and its constraints on gold-silver mineralization in Xiong'ershan area, western Henan Province. Mineral Resources and Geology, 20(4-5): 427–429.
[] Hu SX, Lin QL. 1988. Geology and Metallogeny of the Collision Belt between the North and the South China Plates. Nanjing: Nanjing University Press.
[] Hu SX, Wang HN, Wang DZ, Zhang JR. 1998. Geology and Geochemistry Gold Deposits in East China. Beijing: Science Press.
[] Hu ZH, Hu SX. 1990. The yanshanian interacontinental compression-subduction in the northern part of the East-Qinling area: Its tectonic model and evidences. Journal of Nanjing University (Natural Sciences Edition), 26(3): 489–498.
[] Jackson SE, Pearson NJ, Griffin WL, Belousova EA. 2004. The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology. Chemical Geology, 211(1-2): 47–69. DOI:10.1016/j.chemgeo.2004.06.017
[] Jiang SY, Dai BZ, Jiang YH, Zhao HX, Hou ML. 2009. Jiaodong and Xiaoqinling: Two orogenic gold provinces formed in different tectonic settings. Acta Petrologica Sinica, 25(11): 2727–2738.
[] King PL, White AJR, Chappell BW, Allen CM. 1997. Characterization and origin of aluminous A-type granites from the Lachlan Fold belt, Southeastern Australia. Journal of Petrology, 38(3): 371–391. DOI:10.1093/petroj/38.3.371
[] Kinny PD, Maas R. 2003. Lu-Hf and Sm-Nd isotope systems in zircon. Reviews in Mineralogy and Geochemistry, 53(1): 327–341. DOI:10.2113/0530327
[] Knudsen TL, Griffin WL, Hartz EH, Andresen A, Jackson SE. 2001. In-situ hafnium and lead isotope analyses of detrital zircons from the Devonian sedimentary basin of NE Greenland: A record of repeated crustal reworking. Contributions to Mineralogy and Petrology, 141(1): 83–94. DOI:10.1007/s004100000220
[] Li HM, Ye HS, Mao JW, Wang DH, Chen YC, Qu WJ, Du AD. 2007. Re-Os dating of molybdenites from Au (-Mo) deposits in Xiaoqinling gold ore district and its geological significance. Mineral Deposits, 26(4): 417–424.
[] Li N, Lai Y, Lu YH, Guo DS. 2008. Study of fluid inclusions and ore genetic type of the Qiyugou gold deposit, Henan. Geology in China, 35(6): 1230–1239.
[] Li YF, Mao JW, Guo BJ, Hu HB, Bai FJ. 2004. Geology, geochemistry and genesis of Gongyu altered tectonite type gold deposit in western Henan Province. Mineral Deposits, 23(1): 61–66.
[] Li YF, Mao JW, Hu HB, Bai FJ, Li HM, Li MW, Guo BJ, Ye HS. 2005. The fluid inclusions and their He-Ar-S-H-O isotopic compositions and tracing to the source of ore-forming fluids for the Gongyu gold deposit, western Henan. Acta Petrologica Sinica, 21(5): 1347–1358.
[] Liu CS, Chen XM, Chen PR, Wang RC, Hu H. 2003. Subdivision, discrimination criteria and genesis for a type rock suites. Geological Journal of China Universities, 9(4): 573–591.
[] Liu YJ, Ma DS. 1991. Geochemistry of Gold. Beijing: Science Press: 118-119.
[] Lu XX, Wei XD, Yu ZP, Ye AW. 2003. Characteristics of ore-forming fluids in gold deposits of Xiaoqinling-Xiong'ershan area. Mineral Deposits, 22(4): 377–385.
[] Lu XX, Wei XD, Dong Y, Yu ZP, Chang QL, Zhang GS, Liu SL, Ye AW, Suo YT, Jin JP. 2004. The Characteristics of Gold Deposits and Mantle Fluids of Xiaoqinling-Xiongershan Region. Beijing: Geological Publishing House.
[] Ludwig KR. 2001. Isoplot/Ex (rev.)2.49: A geochronological toolkit for microsoft excel. Berkeley Geochronology Center, Special Publication, 1: 1–58.
[] Maniar PD, Piccoli PM. 1989. Tectonic discrimination of granitoids. Geological Society of America Bulletin, 101(5): 635–643. DOI:10.1130/0016-7606(1989)101<0635:TDOG>2.3.CO;2
[] Mao JW, Goldfarb RJ, Zhang ZW, Xu WY, Qiu YM, Deng J. 2002. Gold deposits in the Xiaoqinling-Xiong'ershan region, Qinling Mountains, Central China. Mineralium Deposita, 37(3-4): 306–325. DOI:10.1007/s00126-001-0248-1
[] Mao JW, Xie GQ, Zhang ZH, Li XF, Wang YT, Zhang CQ, Li YF. 2005. Mesozoic large-scale metallogenic pulses in North China and corresponding geodynamic settings. Acta Petrologica Sinica, 21(1): 169–188.
[] McDonough WF, Sun SS. 1995. The composition of the Earth. Chemical Geology, 120(3-4): 223–253. DOI:10.1016/0009-2541(94)00140-4
[] Meng QR, Zhang GW. 2000. Geologic framework and tectonic evolution of the Qinling orogen, Central China. Tectonophysics, 323(3-4): 183–196. DOI:10.1016/S0040-1951(00)00106-2
[] Patchett PJ, Kouvo O, Hedge CE, Tatsumoto M. 1981. Evolution of continental crust and mantle heterogeneity: Evidence from Hf isotopes. Contributions to Mineralogy and Petrology, 78(3): 279–297.
[] Pearce JA. 1996. Sources and settings of granitic rocks. Episodes, 19(4): 120–125.
[] Ren FG, Ding SY, Zhao JN, Li ZH. 1999. The features of explosive breccia gold deposits and ore-hunting indicators in Xionger mountain-Waifang mountain. Progress in Precambrian Research, 22(2): 32–38.
[] Ren JS, Chen TY, Niu BG, Liu ZG, Liu FR. 1992. Tectonic Evolution of Continental Lithosphere and Ore-forming beneath East China and Its Adjacent Areas. Beijing: Science Press: 1-230.
[] Rui ZY, Zhao YM, Wang LS, Wang YT. 2003. Role of volatile components in formation of skarn and porphyry deposits. Mineral Deposits, 22(2): 141–148.
[] Scherer E, Münker C, Mezger K. 2001. Calibration of the lutetium-hafnium clock. Science, 293(5530): 683–687. DOI:10.1126/science.1061372
[] Swanson SE. 1977. Relation of nucleation and crystal-growth rate to the development of granitic textures. American Mineralogist, 62: 966–978.
[] Tang HF, Zhao ZQ, Huang RS, Han YJ, Su YP. 2008. Primary Hf isotopic study on zircons from the A-type granites in eastern Junggar of Xinjiang, Northwest China. Acta Mineralogica Sinica, 28(4): 335–342.
[] Vervoort JD, Patchett PJ, Gehrels GE, Nutman AP. 1996. Constraints on early Earth differentiation from hafnium and neodymium isotopes. Nature, 379(6566): 624–627. DOI:10.1038/379624a0
[] Vervoort JD, Blichert-Tolf J. 1999. Evolution of the depleted mantle: Hf isotope evidence from juvenile rocks through time. Geochimica et Cosmochimica Acta, 63(3-4): 533–556. DOI:10.1016/S0016-7037(98)00274-9
[] Wang YT, Mao JW, Lu XX. 2001. 40Ar-39Ar dating and geochronological constraints on the ore-forming epoch of the Qiyugou gold deposit in Songxian County, Henan Province. Geological Review, 47(5): 551–555.
[] Wang YT, Mao JW. 2002. Mineralization in the post-collisional orogenic extensional regime: A case study of the Xiaoqinling gold deposit clustering area. Geological Bulletin of China, 21(8-9): 562–566.
[] Watson EB, Harrison TM. 1983. Zircon saturation revisited: Temperature and composition effects in a variety of crustal magma types. Earth and Planetary Science Letters, 64(2): 295–304. DOI:10.1016/0012-821X(83)90211-X
[] Webster JD and Holloway JR. 1990. Partitioning of F and Cl between magmatic hydrothermal fluids and highly evolved granitic magmas. In: Stein HJ and Hannah JL (eds.). Ore-bearing Granite Systems: Petrogenesis and Mineralizing Processes. Geological Society of America Special Paper, 246: 21-34
[] Whalen JB, Currie KL, Chappell BW. 1987. A-type granites: Geochemical characteristics, discrimination and petrogenesis. Contributions to Mineralogy and Petrology, 95(4): 407–419. DOI:10.1007/BF00402202
[] Wright JB. 1969. A simple alkalinity ratio and its application to questions of non-orogenic granite genesis. Geological Magazine, 106(4): 370–384. DOI:10.1017/S0016756800058222
[] Wu FY, Li XH, Zheng YF, Gao S. 2007. Lu-Hf isotopic systematics and their applications in petrology. Acta Petrologica Sinica, 23(2): 185–220.
[] Wu YB, Zheng YF. 2004. Genesis of zircon and its constraints on interpretation of U-Pb age. Chinese Science Bulletin, 49(15): 1554–1569. DOI:10.1007/BF03184122
[] Xu QD, Zhong ZQ, Zhou HW, Yang FC, Tang XC. 1998. 40Ar/39Ar dating of the Xiaoqinling gold area in Henan Province. Geological Review, 44(3): 323–327.
[] Xu XS, Griffin WL, Ma X, O'Reilly SY, He ZY, Zhang CL. 2009. The Taihua group on the southern margin of the North China Craton: Further insights from U-Pb ages and Hf isotope compositions of zircons. Mineralogy and Petrology, 97(1-2): 43–59. DOI:10.1007/s00710-009-0062-5
[] Yang SY, Jiang SY, Jiang YH, Zhao KD, Fan HH. 2010. Zircon U-Pb geochronology, Hf isotopic composition and geological implications of the rhyodacite and rhyodacitic porphyry in the Xiangshan uranium ore field, Jiangxi Province, China. Science China (Earth Sciences), 53(10): 1411–1426. DOI:10.1007/s11430-010-4058-0
[] Yang SY, Jiang SY, Jiang YH, Zhao KD, Fan HH. 2011. Geochemical, zircon U-Pb dating and Sr-Nd-Hf isotopic constraints on the age and petrogenesis of an Early Cretaceous volcanic-intrusive complex at Xiangshan, Southesat China. Mineralogy and Petrology, 101(1-2): 21–48. DOI:10.1007/s00710-010-0136-4
[] Yang SY, Jiang SY, Zhao KD, Jiang YH, Ling HF, Luo L. 2012. Geochronology, geochemistry and tectonic significance of two Early Cretaceous A-type granites in the Gan-Hang Belt, Southeast China. Lithos, 150: 155–170. DOI:10.1016/j.lithos.2012.01.028
[] Yao JM, Zhao TP, Li J, Sun YL, Yuan ZL, Chen W, Han J. 2009. Melybdenite Re-Os age and zircon U-Pb age and Hf isotope geochemistry of the Qiyugou gold system, Henan Province. Acta Petrologica Sinica, 25(2): 374–384.
[] Zhang DH, Zhang WH, Xu GJ. 2001. Exsolution and evolution of magmatic hydrothermal fluids and their constraints on the porphyry ore-forming system. Earth Science Frontiers, 8(3): 193–202.
[] Zhang GW, Meng QR, Liu SF, Yao AP. 1997. Huge intracontinental subduction zone at south margin of north china block and present 3-D lithospheric framework of the Qinling orogenic belt. Geological Journal of China Universities, 3(2): 129–143.
[] Zhang GW, Zhang BR, Yuan XC. 2001. Qinling Belt and Continental Dynamical. Beijing: Science Press: 1-729.
[] Zhang GW, Dong YP, Lai SC, Guo AL, Meng QR, Liu SF, Cheng SY, Yao AP, Zhang ZQ, Pei XZ, Li SZ. 2003. The Mian-Lue suture zone in the South Qinling-Dabie Orogenic Belt. Science in China (Series D), 33(12): 1121–1135.
[] Zhao HX, Frimmel HE, Jiang SY, Dai BZ. 2011a. LA-ICP-MS trace element analysis of pyrite from the Xiaoqinling gold district, China: Implications for ore genesis. Ore Geology Reviews, 43(1): 142–153. DOI:10.1016/j.oregeorev.2011.07.006
[] Zhao HX, Jiang SY, Frimmel HE. 2011b. A rare Bi-Pb tellurosulphide PbBi4Te4S3 from the Wenyu gold deposit, in the Xiaoqinling district (China). Canadian Mineralogist, 49(5): 1297–1304. DOI:10.3749/canmin.49.5.1297
[] Zhao HX, Jiang SY, Frimmel HE, Dai BZ, Ma L. 2012a. Geochemistry, geochronology and Sr-Nd-Hf isotopes of two Mesozoic granitoids in the Xiaoqinling gold district: Implication for large-scale lithospheric thinning in the North China Craton. Chemical Geology, 294-295: 173–189. DOI:10.1016/j.chemgeo.2011.11.030
[] Zhao KD, Jiang SY, Zhu JC, Li L, Dai BZ, Jiang YH, Ling HF. 2010. Hf isotopic composition of zircons from the Huashan-Guposhan intrusive complex and their mafic enclaves in northeastern Guangxi: Implication for petrogenesis. Chinese Science Bulletin, 55(6): 509–519. DOI:10.1007/s11434-009-0314-0
[] Zhao KD, Jiang SY, Yang SY, Dai BZ, Lu JJ. 2012b. Mineral chemistry, trace elements and Sr-Nd-Hf isotope geochemistry and petrogenesis of Cailing and Furong granites and mafic enclaves from the Qitianling batholith in the Shi-Hang zone, South China. Gondwana Research, 22(1): 310–324. DOI:10.1016/j.gr.2011.09.010
[] Zhong WG, Wang YJ, Zang XN, Dong ZS. 2005. Origin study on porphyritic crystals in coarse feldspar of Yishan granites in western Shandong. Land and Resources in Shandong Province, 21(6-7): 64–66.
[] Zhou ZJ, Jiang SY, Qin Y, Zhao HX, Hu CJ. 2011. Fluid inclusion characteristics and ore genesis of the Wenyu gold deposit, Xiaoqinling gold belt. Acta Petrologica Sinica, 27(12): 3787–3799.
[] Zhu JW, Zhang TY, Xue LW. 1999. Determination of the ore-forming age of gold deposits in Xiaoshan, western Henan and its geological significance. Geological Review, 45(4): 418–422.
[] Zhu LM, Zhang GW, Li B, Guo B. 2008. Main geological events, genetic types of metallic deposits and their geodynamical setting in the Qinling Orogenic Belt. Bulletin of Mineralogy, Petrology and Geochemistry, 27(4): 384–390.
[] 毕献武, 骆庭川. 1995. 洛宁花山岩体地球化学特征及成因的探讨. 矿物学报, 15(4): 433–441.
[] 陈衍景, 富士谷. 1992. 豫西金矿成矿规律. 北京: 地震出版社.
[] 陈衍景, 富士谷, 胡受奚. 1992. 论豫西金矿的成矿时代. 有色金属矿产与勘查, 1(3): 140–144.
[] 陈衍景, 隋颖慧, PirajnoF. 2003. CMF模式的排他性依据和造山型银矿实例:东秦岭铁炉坪银矿同位素地球化学. 岩石学报, 19(3): 551–568.
[] 戴宝章, 蒋少涌, 王孝磊. 2009. 河南东沟钼矿花岗斑岩成因:岩石地球化学、锆石U-Pb年代学及Sr-Nd-Hf同位素制约. 岩石学报, 25(11): 2887–2899.
[] 第五春荣, 孙勇, 林慈銮, 柳小明, 王洪亮. 2007. 豫西宜阳地区TTG质片麻岩锆石U-Pb定年和Hf同位素地质学. 岩石学报, 23(2): 253–262.
[] 范宏瑞, 谢奕汉, 王英兰. 1994. 豫西花山花岗岩基岩石学和地球化学特征及其成因. 岩石矿物学杂志, 13(1): 19–32.
[] 范宏瑞, 谢奕汉, 王英兰. 1998. 豫西上宫构造蚀变岩型金矿成矿过程中的流体-岩石反应. 岩石学报, 14(4): 529–541.
[] 范宏瑞, 谢奕汉, 郑学正, 王英兰. 2000. 河南祁雨沟热液角砾岩体型矿床成硫流体研究. 岩石学报, 16(4): 559–563.
[] 郭东升, 陈衍景, 祁进平. 2007. 河南祁雨沟金矿同位素地球化学和矿床成因分析. 地质论评, 53(2): 217–227.
[] 胡海珠, 李毅. 2006. 豫西熊耳山地区燕山期岩浆作用对金银成矿的制约因素. 矿产与地质, 20(4-5): 427–429.
[] 胡受奚, 林潜龙. 1988. 华北与华南古板块拼合带地质和成矿. 南京: 南京大学出版社.
[] 胡受奚, 王鹤年, 王德滋, 张景荣. 1998. 中国东部金矿地质学及地球化学. 北京: 科学出版社.
[] 胡志宏, 胡受奚. 1990. 东秦岭燕山期大陆内部挤压俯冲的构造模式及其证据. 南京大学学报(自然科学版), 26(3): 489–498.
[] 蒋少涌, 戴宝章, 姜耀辉, 赵海香, 侯明兰. 2009. 胶东和小秦岭:两类不同构造环境中的造山型金矿省. 岩石学报, 25(11): 2727–2738.
[] 李厚民, 叶会寿, 毛景文, 王登红, 陈毓川, 屈文俊, 杜安道. 2007. 小秦岭金(钼) 矿床辉钼矿铼-锇定年及其地质意义. 矿床地质, 26(4): 417–424.
[] 李诺, 赖勇, 鲁颖淮, 郭东生. 2008. 河南祁雨沟金矿流体包裹体及矿床成因类型研究. 中国地质, 35(6): 1230–1239.
[] 李永峰, 毛景文, 郭保健, 胡华斌, 白凤军. 2004. 豫西公峪金矿床地质地球化学特征及成因探讨. 矿床地质, 23(1): 61–66.
[] 李永峰, 毛景文, 胡华斌, 白凤军, 李厚民, 李蒙文, 郭保健, 叶会寿. 2005. 豫西公峪金矿床流体包裹体及其He、Ar、S、H、O同位素组成对成矿流体来源的示踪. 岩石学报, 21(5): 1347–1358.
[] 刘昌实, 陈小明, 陈培荣, 王汝成, 胡欢. 2003. A型岩套的分类、判别标志和成因. 高校地质学报, 9(4): 573–591.
[] 刘英俊, 马东升. 1991. 金的地球化学. 北京: 科学出版社: 118-119.
[] 卢欣祥, 尉向东, 于在平, 叶安旺. 2003. 小秦岭-熊耳山地区金矿的成矿流体特征. 矿床地质, 22(4): 377–385.
[] 卢欣祥, 尉向东, 董有, 于在平, 常秋玲, 张冠山, 刘树林, 叶安旺, 索元天, 晋建平. 2004. 小秦岭-熊耳山地区金矿特征与地幔流体. 北京: 地质出版社.
[] 毛景文, 谢桂青, 张作衡, 李晓峰, 王义天, 张长青, 李永峰. 2005. 中国北方中生代大规模成矿作用的期次及其地球动力学背景. 岩石学报, 21(1): 169–188.
[] 任富根, 丁士应, 赵嘉农, 李增慧. 1999. 熊耳山-外方山区爆破角砾岩型金矿床的特征和有关找矿问题. 前寒武纪研究进展, 22(2): 32–38.
[] 任纪舜, 陈廷愚, 牛宝贵, 刘志刚, 刘凤仁. 1992. 中国东部及邻区大陆岩石圈的构造演化与成矿. 北京: 科学出版社: 1-230.
[] 芮宗瑶, 赵一鸣, 王龙生, 王义天. 2003. 挥发份在夕卡岩型和斑岩型矿床形成中的作用. 矿床地质, 22(2): 141–148.
[] 唐红峰, 赵志琦, 黄荣生, 韩宇捷, 苏玉平. 2008. 新疆东准噶尔A型花岗岩的锆石Hf同位素初步研究. 矿物学报, 28(4): 335–342.
[] 王义天, 毛景文, 卢欣祥. 2001. 嵩县祁雨沟金矿成矿时代的40Ar-39Ar年代学证据. 地质论评, 47(5): 551–555.
[] 王义天, 毛景文. 2002. 碰撞造山作用期后伸展体制下的成矿作用--以小秦岭金矿集中区为例. 地质通报, 21(8-9): 562–566.
[] 吴福元, 李献华, 郑永飞, 高山. 2007. Lu-Hf同位素体系及其岩石学应用. 岩石学报, 23(2): 185–220.
[] 徐启东, 钟增球, 周汉文, 杨发城, 唐学超. 1998. 豫西小秦岭金矿区的一组40Ar/39Ar定年数据. 地质论评, 44(3): 323–327.
[] 姚军明, 赵太平, 李晶, 孙亚莉, 原振雷, 陈伟, 韩军. 2009. 河南祁雨沟金成矿系统辉钼矿Re-Os年龄和锆石U-Pb年龄及Hf同位素地球化学. 岩石学报, 25(2): 374–384.
[] 张德会, 张文淮, 许国建. 2001. 岩浆热液出溶和演化对斑岩成矿系统金属成矿的制约. 地学前缘, 8(3): 193–202.
[] 张国伟, 孟庆任, 刘少峰, 姚安平. 1997. 华北地块南部巨型陆内俯冲带与秦岭造山带岩石圈现今三维结构. 高校地质学报, 3(2): 129–143.
[] 张国伟, 张本仁, 袁学诚. 2001. 秦岭造山带与大陆动力学. 北京: 科学出版社: 1-729.
[] 张国伟, 董云鹏, 赖绍聪, 郭安林, 孟庆任, 刘少峰, 程顺有, 姚安平, 张宗清, 裴先治, 李三忠. 2003. 秦岭-大别造山带南缘勉略构造带与勉略缝合带. 中国科学(D辑), 33(12): 1121–1135.
[] 仲卫国, 王聿军, 臧学农, 董作森. 2005. 鲁西峄山花岗岩中粗大钾长石斑晶成因探讨. 山东国土资源, 21(6-7): 64–66.
[] 周振菊, 蒋少涌, 秦艳, 赵海香, 胡春杰. 2011. 小秦岭文峪金矿床流体包裹体研究及矿床成因. 岩石学报, 27(12): 3787–3799.
[] 朱嘉伟, 张天义, 薛良伟. 1999. 豫西崤山地区金矿成矿年龄的测定及其意义. 地质论评, 45(4): 418–422.
[] 朱赖民, 张国伟, 李犇, 郭波. 2008. 秦岭造山带重大地质事件、矿床类型和成矿大陆动力学背景. 矿物岩石地球化学通报, 27(4): 384–390.