Formation Age and Geochemical Characteristics of Dishantou Monzonitic Granite in Estern Kunlun Orogenic Belt
-
摘要: 对东昆仑造山带中段低山头一带二长花岗岩体开展锆石U-Pb测年和岩石地球化学研究，获得二长花岗岩锆石U-Pb定年为（225.52±0.76） Ma，属晚三叠世印支期。岩石地球化学特征显示：Al2O3含量为14.73%~16.42%，里特曼组合指数σ43值为1.18~1.46，属钙碱性系列，K2O/Na2O<1，具富钠贫钾的特点，A/NCK值主要为0.94~0.99，属偏铝质岩浆岩；大离子亲石元素（LILE）富集Rb、K、Sr、Ba，高场强元素（HFSE）富集Th、U、La、Ce，而Nb、Ti明显亏损；其轻重稀土比值LREE/HREE为6.06~16.98，δCe为0.95~0.99，显示为负异常，（La/Yb）N为7.46~28.35，轻稀土显示富集；δEu在0.51~0.92，总体属Eu亏损型；Eu负异常特征显示岩浆分异明显。岩体属I型花岗岩，结合构造环境判别图解，综合判断低山头一带二长花岗岩属东昆仑中段晚三叠世火山弧型花岗岩。Abstract: Ziron U-Pb dating and petrological geochemistry of Ditoushan monzonitic granite in the middle section of Estern Kunlun Orogenic Belt have carried out in this paper. Ziron U-Pb dating of monzonitic granite yields an age of (225.52±0.76)Ma, showing that the Ditoushan monzonitic granite was generated in late Triassic Indo-Chinese epoch. Petrological geochemistry research show that Al2O3 content vary from 14.73% to 16.42% while Rittmann index change from 1.18 to 1.46, suggesting that these rocks belong to calc alkalic series. Their K2O/Na2O ratio less than 1, showing the features of enriched sodium and depleted potassium. Their A/NCK range from 0.94 to 0.99, belonging to aluminous magmatic rock, with richment of large ionic lithophile element (LILE, such as Rb, K, Sr and Ba) and high strength field elements (HFSE, including Th, U, La and Ce), but obviously poor of Nb and Ti. Their LREE/HREE ratios vary from 6.06 to 16.98, while δCe values range from 0.95 to 0.99, showing negative anomaly. Their (La/Yb)N ratios change from 7.46 to 28.35, showing rich LREE; Their δEu values vary from 0.51to 0.92, displaying negative Eu anomaly and showing distinct magmatic differentiations. These rocks belong to I-type granite. Combined with geotectonic discrimination diagram, it's comprehensively judged that the Ditoushan monzonitic granite belongs to late Triassic volcanic arc granitoids formed in the middle Estern Kunlun Orogenic Belt.
-
Keywords:
- monzonitic granite /
- zircon U-Pb dating /
- Late Triassic /
- East Kunlun
-
-
莫宣学,潘桂棠.从特提斯到青藏高原形成:构造岩浆事件的约束[J].地学前缘,2006,13(6):43-51. MO Xuanxue, PAN Guitang. From the Tethys to the formation of the Qinghai-Tibet Plateau:Constrainedby tectonic-magmatic events[J].Earth Science Frontiers,2006,13(6):43-51.
莫宣学,罗照华,邓晋福,等.东昆仑造山带花岗岩及地壳生长[J].高校地质学报,2007,13(3):403-414. MO Xuanxue, LUO Zhaohua,,DENG Jinfu,et al. Granitoids and Crustal Growth in the East-Kunlun Orogenic Belt[J].Geological Journal of China Universities,2007,13(3):403-414.
杜玉良,贾群子,韩生福.青海东昆仑成矿带中生代构造岩浆成矿作用及铜金多金属找矿研究[J].西北地质,2012,45(4):69-75. DUI Yuliang,JIA Qunzi,HAN Shenfu.MesozoicTectono-Magmatic-Mineralization and Copper-Gold Polymetallic Ore Prospecting Research in East Kun LunMetallogenicBeltin Qinghai[J].Northwestern Geology, 2012,45(4):69-75.
丰成友,张德全,王富春,等.青海东仑复合造山过程及典型造山型金矿地质[J].地球学报, 2004, 25(4):415-422. FENG Chengyou,ZHANG Dequan,WANG Fuchun,et al.Multiple Orogenic Processes and Geologicai Characteristics of the Major Orogenic Gold Deposits in East Kunlun Area,Qinghai Province[J].Acta Geoscientia Sinica,2004, 25(4):415-422.
古凤宝.东昆仑地质特征及晚古生代-中生代构造演化[J].青海地质,1994,1:4-14. GU Fengbao.Geological Characteristics of East Kunlun and Tectonic Evolution in Late Palaezoic-Mesozoic Era[J]. Qinghai Geology,1994,1:4-14.
邓红宾,姚波,钟刚,等.青海省格尔木市格尔木河西地区J46E023018等五幅1:5万区域地质矿产调查报告[R].绵阳:四川省地质矿产勘查开发局川西北地质队,2016,78-231. 潘桂棠,王立全,张万平,等.青藏高原及邻区大地构造图及说明书(1:150万)[M].北京:地质出版社,2013,11-153. PAN Guitang,WANG Lliquan, ZHANG Wanquan, et al.Tectonic maps and manuals of the Qinghai-Tibet Plateau and its adjacent areas(1:150 million)[M]. Beijiang:Geological Publishing House,2013,11-153.
侯可军,李延河,田有荣.LA-MC-ICP-MS锆石微区原位U-Pb定年技术[J].矿床地质,2009, 28(4):481-492. HOU Kejun, LI Yanhe, TIAN Yourong. In situ U-Pb zircon dating using laser ablation-multi ion counting-ICP-MS[J]. Mineral Deposits, 2009,28(4):481-492.
邱家骧.岩石化学[M].北京:地质出版社,1991,65-67. QIU Jiaxiang. Petrochemistry[M].Beijiang:Geological Publishing House,1991,65-67.
洪大卫,郭文歧,李戈晶,等.福建沿海晶洞花岗岩带的岩石学和成因演化[M].北京:科学技术出版社,1987,1-132. HONG Dawei, GUO Wenqi, LI Gejin, et al.Fujian coastalpetrography lithology of Crystal Cave Granite Belt and genesis evolution[M].Beijing:Science and Technology Press,1987,1-132.
张智勇,朱迎堂,周光第,等,兴海幅1:25万区域地质调查报告[R].青海省地质调查院,2001. 丰成友,李东生,吴正寿,等.东昆仑祁漫塔格成矿带矿床类型、时空分布及多金属成矿作用[J].西北地质,2010,43(4):10-17. FENG Chengyou, LI Dongsheng, WU Zhengshou et al. Major Types, Time-Space Distribution and Metallogeneses of Polymetallic Deposits in the Qimantage Metallogenic Belt, Eastern Kunlun Area[J].Northwestern Geology,2010,43(4):10-17.
郭通珍,谈生祥,丁玉进,等,青海1:5万乌兰乌珠尔-祁漫塔格地区八幅区域地质调查报告[R].青海省地质调查院,2011, 137-138. 韩海臣,王国良,丁玉进,等,东昆仑巴音呼都森晚三叠世中酸性侵入岩锆石LA-ICP-MS U-Pb定年及地质意义[J].西北地质,2018,51(1):144-158. HAN Haichen,WANG Guoliang,DING Yujin, et al.LA-ICP-MS Zircon U-Pb Age of Late Triassic Intrusive Rocks in Bayinhudousen Area,East Kunlun and Its Tectonic Significance[J].Northwestern Geology,2018,51(1):144-158.
国显正,贾群子,栗亚芝,等,东昆仑热水二长花岗岩地球化学特征、年代学及其构造意义[J].矿物岩石地球化学通报,2016,35(6),1319-1328. GUO Xianzheng, JIA Qunzi,LI Yazhi, et al. Zircon U-Pb Geochronology and Geochemical Characteristics of the ReshuiMonzogranite in the Eastern Kunlun and Their Tectonic Significances[J]. Bulletin of Mineralogy, Petrology and Geochemistry, 2016,35(6):1319-1328.
CHAPPEll B W. Aluminium saturation in I-and S-type granites and the characterization of fractionated haplogranites[J]. Lithos, 1999, 46(3):535-551.
CHAPPELL B W, WHITE A J R. I-and S-type granites in the Lachlan Fold Belt[J]. Geological Society of America Special Papers, 1992, 272:1-26.
CHAPPELL B W,WHITE AJR.Two constrasting granite types[J].Pacific Geology,1974,8:173-174.
CHAPPELL B W, WHITE AJR.Two contrasting granite types:25years later[J].Australian Journal of Earth Sciences,2001,48(4):489-499.
W J Collins,S D Beams,A J R White,et al.Nature and origin of A type granites with paticular reference to Southeastern Australia[J]. Contrib. Miner. Petro, 1982,80(2),189-200.
HARRIS NB,WPEARCE JA, TINDEL AG.Geochemicai characteristics of collision-zone magmatism.In:Coward and reis(eds.)Collision Tectonics[J].GSA Pub, 1986,19:67-81.
LIU Y S,GAO S,HU Z C, et al.Continental and oceanic crust recycling-induced melt-peridotite interactions in the Trans-North China Orogen:U-Pbdating,Hf isotopes and trace elements in zircons from mantle xenoliths[J]. Journal of Petrology, 2010,51(51):392-9.
PEARCEJ A, HARRIS NBW, TINDLE A G. Trace element discrimination diagrams for the tectonic interpretation of granitic rocks[J]. Journal of Petrology, 1984, 25:956-983.
STRECKEISENA L. Classification and nomenclarure of plutonic rocks:recommendations[M], N. Jb. Miner. Monat. Jg.,1973,149-164.
计量
- 文章访问数: 2106
- HTML全文浏览量: 0
- PDF下载量: 2151
下载:
