新生矿区花岗岩体岩性为黑云母花岗岩和黑云母二长花岗岩。花岗岩总体上具有富钾、高硅的特征，为钙碱性到弱过铝质花岗岩的过渡(A/CNK为0.93~1.13)。花岗岩具有强烈的Eu负异常(δEu为0.15~0.35)，稀土元素配分曲线呈不对称的“海鸥型”，与典型过铝质A型花岗岩的特征一致。花岗岩的10000Ga/Al为3.62(3.47~4.00)，与世界A型花岗岩平均值3.75相接近。锆石U-Pb年龄为(147.5±3.5) Ma(MSWD=2.6)，显示岩体形成于燕山早期第二阶段。锆石的εHf(t)为-5.79~-4.15，暗示岩浆来源于均一源区，锆石的Hf同位素两阶段模式年龄(TDM2)为1.208~1.290 Ga，平均为1.227 Ga，说明岩浆源区有中元古代的古老地壳物质的加入。花岗岩构造环境判别图解显示为造山后(A2)的板内花岗岩。成矿花岗岩是在燕山早期晚阶段板内拉张背景下侵入地壳，并带来成矿物质形成矽卡型铜多金属矿床。
The Xinsheng granite bodies are distinguished as biotite granite and biotite monzogranite in mining area, the granites can be classified to be calc-alkaline granite and weakly peraluminous granite with K-rich, Si-high (the values of A/CNK are 0.93-1.13). The granites have obvious Eu negative anomaly, the REE distribution patterns be long to the type of “gull”, which are the same as that of typical A-type granite. The average value of 10 000Ga/Al of granites is 3.62 (3.47-4.00), which is close to 3.75, the average value of A-type granite worldwide. The zircon U-Pb age of granite bodies is (147.5±3.5) Ma (MSWD=2.6), which shows that they formed in the second stage of early Yanshan movement. The values ofεHf(t) are-5.79--4.15, indicating that the magma mainly derived from a uniform resource. The model ages of two-stage range of zircon Hf isotope (TDM2) are 1.208-1.290 Ga (average value is 1.227 Ga). This feature indicates that the granite bodies originated from melting of early crustal materials formed in mesoproterozoic. The discrimination diagrams for tectonic background of granites prove that the granites formed in intra-plate extension environment, and the granites are A2-type, so, the granite body intrusived to lower crust in extension environment, and brought enough mineralizing material to form skarn type copper polymetallic deposit.
参考文献
| [1] | 伍光英,潘仲芳,侯增谦,李金冬,车勤建,陈辉明.湖南大义山锡多金属矿田矿体分布规律、控矿因素及找矿方向[J].地质与勘探,2005(02):6-11. |
| [2] | 费利东,全铁军,孔华,王高,郭碧莹.湖南省永兴县新生矿区隐伏岩体地质地球化学特征及其与成矿的关系[J].地质与勘探,2012(01):110-118. |
| [3] | LIU Y S;GAO S;HU Z C;GAO C G ZONG K Q WANG D B .Continental and oceanic crust recycling-induced melt-peridotite interactions in the Trans-North China Orogen:U-Pb dating,Hf isotopes and trace elements in zircons of mantle xenoliths[J].Journal of Petrology,2010,51(1/2):537-571. |
| [4] | Andersen T. .Correction of common lead in U-Pb analyses that do not report Pb-204[J].Chemical geology,2002(1/2):59-79. |
| [5] | LUDWIG K R.User’s Manual for Isoplot 3.0:A geochronological toolkit for microsoft excel[M].California:Berkeley Geochronology Center,Special Publication,2003:1-71. |
| [6] | Yuan HL;Gao S;Dai MN;Zong CL;Gunther D;Fontaine GH;Liu XM;Diwu C .Simultaneous determinations of U-Pb age, Hf isotopes and trace element compositions of zircon by excimer laser-ablation quadrupole and multiple-collector ICP-MS[J].Chemical geology,2008(1-2):100-118. |
| [7] | RICKWOOD P C .Boundary lines within petrologic diagrams which use oxides of major and minor elements[J].LITHOS,1989,22(04):247-263. |
| [8] | 赵振华,熊小林,韩小东.花岗岩稀土元素四分组效应形成机理探讨--以千里山和巴尔哲花岗岩为例[J].中国科学D辑,1999(04):331-338. |
| [9] | 薛怀民,汪应庚,马芳,汪诚,王德恩,左延龙.高度演化的黄山A型花岗岩：对扬子克拉通东南部中生代岩石圈减薄的约束?[J].地质学报,2009(02):247-259. |
| [10] | 李昌年.火成岩微量元素岩石学[M].武汉:中国地质大学出版社,1992:171-181. |
| [11] | 路远发.GeoKit：一个用 VBA构建的地球化学工具软件包[J].地球化学,2004(05):459-464. |
| [12] | Hawkesworth CJ;Kemp AI .Evolution of the continental crust.[J].Nature,2006(7113):811-817. |
| [13] | 郭春丽 .赣南崇义-上犹地区与成矿有关中生代花岗岩类的研究及对南岭地区中生代成矿花岗岩的探讨[D].北京:中国地质科学院,2010. |
| [14] | NOWELL G M;KEMPTON P D;NOBLE S P;FITTON J G SAUNDERS A D MAHONEY J J TAYLOR R N .Highprecision Hf isotope measurements of MORB and OIB by thermal ionisation mass spectrometry:Insights into the depleted mantle[J].Chemical Geology,1998,149(3/4):211-233. |
| [15] | Jeff D. Vervoort;Janne Blichert-Toft .Evolution of the depleted mantle: Hf isotope evidence from juvenile rocks through time[J].Geochimica et Cosmochimica Acta: Journal of the Geochemical Society and the Meteoritical Society,1999(3-4):533-556. |
| [16] | PEARCE J A;HARRIS N B W;TINDLE A G .Trace element discrimination diagrams for the tectonic interpretation of granitic rocks[J].Journal of Petrology,1984,25(04):956-983. |
| [17] | 肖庆辉;王涛;邓晋福;莫宣学 卢欣祥 洪大卫 谢才富 罗照华 邱瑞照 王晓霞.中国典型造山带花岗岩与大陆地壳生长研究[M].北京:地质出版社,2009:1-528. |
| [18] | WHALEN J B;CURRIE K L;CHAPPELL B W .A-type granites:Geochemical characteristics,discrimination and petrogenesis[J].Contributions to Mineralogy and Petrology,1987,95(04):407-419. |
| [19] | EBY G N .Chemical subdivision of the A-type granitoids:Petrogenetic and tectonic implications[J].GEOLOGY,1992,20(07) |
| [20] | 赵振华,包志伟,张伯友,熊小林.柿竹园超大型钨多金属矿床形成的壳幔相互作用背景[J].中国科学D辑,2000(Z1):161-168. |
| [21] | 李兆丽 .锡成矿与A型花岗岩关系的地球化学研究——以湖南芙蓉锡矿田为例[D].中国科学院地球化学研究所,2006. |
| [22] | 蒋少涌,赵葵东,姜耀辉,凌洪飞,倪培.华南与花岗岩有关的一种新类型的锡成矿作用：矿物化学、元素和同位素地球化学证据[J].岩石学报,2006(10):2509-2516. |
| [23] | 朱金初,陈骏,王汝成,陆建军,谢磊.南岭中西段燕山早期北东向含锡钨A型花岗岩带[J].高校地质学报,2008(04):474-484. |
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