Geochronology and Geochemistry of Northern Baiyunshan Granites in the Beishan Area,Inner Mongolia,China and Their Geological Significance
-
摘要: 白云山北正长花岗岩位于红柳河-白云山-洗肠井蛇绿构造混杂岩带以北，长期以来对北山地区早古生代造山结束时间的限定一直存在争议。笔者选择白云山北正长花岗岩进行了LA-ICP-MS锆石U-Pb年代学和地球化学研究。结果表明，白云山北正长花岗岩具有高硅、高碱、低Al2O3、贫CaO和MgO的特征，显示出准铝质-过铝质、碱质花岗岩的特点；∑REE较高，LREE略富集，轻稀土元素分馏明显，重稀土分馏较明显，呈右倾"海鸥型"，Eu负异常明显；强烈富集Rb、Th、U、K等大离子亲石元素，强烈亏损Ba、Sr、P、Ti，并弱亏损Ta、Nb等元素。10 000 Ga/A1较高，为3.64~3.96，锆石饱和温度较高，为808~881℃，具A型花岗岩特征。LA-ICP-MS锆石U-Pb测年表明其形成年龄为（377.3±2.1） Ma，地质时代为晚泥盆世。对岩体特征、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，构造体制为挤压环境向伸展环境的转换。本次工作新厘定出的白云山北晚泥盆世A型花岗岩，对限定北山早古生代造山活动的时间具有重要意义。Abstract: Baiyunshan orthoclase granite is located in the north of the Hongliuhe-Baiyunshan-Xichangjing ophiolitic mélange zone, there has been long controversial about the ending time of the early Paleozoic orogenic in Beishan area.In this paper, LA-ICP-MS zircon U-Pb chronology and geochemistry were studied in Baiyunshan orthoclase granite. The results show that the Baiyunshan orthoclase granite has the characteristics of high silicon, high alkali, low Al2O3, poor CaO and MgO, showing the characteristics of metaluminous-over aluminum and alkaline granite; high ΣREE, LREE slightly enriched,LREE fractionation significant HREE fractionation obviously, obvious negative anomalies of Eu,strongly enriched in Rb, Th, U, K and other large LILE, strongly depleted in Ba, Sr, P, Ti and weak losses of Ta, Nb.10 000Ga/A1 higher, 3.64~3.96, zircon saturation temperature is higher,808~881℃, Exhibited the feature of A-type granites.By LA-ICP-MS zircon U-Pb dating,a weighted mean 206Pb/238U age of (377.3 ±2.1) Ma (MSWD=0.034), is considered to be the formation age of the rock, that is to say Northern Baiyunshan granites were formed in late Devonian.Based on Characteristics of out crops,geochronology, geochemistry and geological setting, the authors hold that the Northern Baiyunshan granitic pluton might be a post-orogenic or late stage orogenic pluton,which formed in the tectonic setting of transformation from collision to extension in late Devonian.The newly developed Devonian A-type granite of the Baiyun Mountain in this work is of great significance to the time of the early Paleozoic orogenic activity.
-
Keywords:
- A-type granite /
- Geochemistry /
- post-orogenic /
- Baiyunshan /
- Beishan
-
-
戴霜,方小敏,张翔,等.塔里木-中朝板块北缘的志留纪公婆泉群火山岩地质地球化学及构造意义[J].兰州大学学报:自然科学版,2003b,39(4):80-87. DAI Shuang,FANG Xiaomin,ZHANG Xiang,et al. Island arc north of the Tarim-SK plate:the geology and geochemistry of Gongpoyuan Croup[J].Journal of Lanzhou University(Natural Sciences),2003b,39(4):80-87.
地质部甘肃省地质局第二区域地质测量队.中华人民共和国地质区域测量报告:石板井幅(K-47-ⅩⅩⅠ)[R].酒泉:地质部甘肃省地质局第二区域地质测量队,1972. 杜刚,李卫红,杨文彬,等.勒巴泉-公婆泉陆缘弧主要特征及动力学背景[J].甘肃地质学报,2003,12(1):16-20. DU Gang,LI Weihung,WANG Wei,et al. The Main Characteristics of Lebaquan-Gongpoquan Epicontinental Arc and the Dynamic Background for its Forming in the Contiguous Area Across Gansu,Xinjiang and inner Mongolia[J].Acta Geologica Gansu,2003,l2(1):16-20.
何世平,任秉琛,姚文光,等.甘肃内蒙古北山地区构造单元划分[J].西北地质,2002,35(4):30-40. HE Shiping, REN Bingshen. YAO Wenguang,et al. The Division of Tectonic Units of Beishan Area, Gansu-Inner Mongolia[J]. Northwestern Geology,2002,35(4):30-40.
何世平,周会武,任秉琛,等.甘肃内蒙古北山地区古生代地壳演化[J].西北地质,2005,38(3):6-15. HE Shiping,ZHOU Huiwu,REN Bingchen,et al. Crustal Evolution of Palaeozoic in Beishan Area, Gansu and Inner Mongolia, China[J]. Northwestern Geology,2005,38(3):6-15.
何世平,周会武,姚文光,等.甘肃北山中泥盆统砾岩中放射虫的发现及其地质意义[J].西北地质, 2004,37(3):24-28. HE Shiping,ZHOU Huiwu,YAO Wenguang, et al. Discovery and Significance of Radiolaria from Middle Devonian Conglomerate in Beishan Area, Gansu[J]. Northwestern Geology,2004,37(3):24-28.
李向民,余吉远,王国强,等.甘肃北山红柳园地区泥盆系三个井组和墩墩山群LA-ICP-MS锆石U-Pb测年及其意义[J].地质通报,2011,30(10):1501-1507. LI Xiangmin,YU Jiyuan,WANG Guoqiang,et al. LA-ICP-MSzircon U-Pb dating of Devonian Sangejing Formation and Dundunshan Group in Hongliuyuan,Beishan area,Gansu Province[J].Geological Bulletin of China,2011,30(10):1501-1507.
柳小明,高山,袁洪林,等.193nmLA-ICPMS对国际地质标准参考物质中42种主量和微量元素的分析. 岩石学报,2002,18(3):408-418. LIU Xiaoming,GAO Shan,YUAN Honglin,et al. Analysis of 42 major and trace elements in glass standard reference materials by 193nm La-ICPMS[J]. Acta Petrologica Sinica,2002,18(3):408-418.
聂凤军,江思宏,白大明,等.北山地区金属矿床成矿规律及找矿方向[M].北京:地质出版社,2002. NIE Fengjun, JIANG Sihong, BAI Daming,et al. Metallogenic Studies and Ore Prospecting in the Conjunction Area of Inner Mongolia Autonomous Region, Gansu Province and Xinjiang Uygur Autonomous Region (Beishan Mt.)[M]. Beijing:Geological Publication,2002.
潘志龙,张欢,陈超,等.内蒙古北山敖包呼图仁斑状正长花岗岩锆石U-Pb年龄、Lu-Hf同位素组成及其地质意义[J].地质科学,2017,52(1):301-316. PAN Zhilong,ZHANG Huan,CHEN Chao,et al.Zircon U-Pbgeochronology and Lu-Hf isotope compositions of porphyritic syenite granite from Aobaohuturen in Beishan,Inner Mongolia and its tectonic implication[J]. Chinese Journal of Geology,2017,52(1):301-316.
王立社,杨建国,王育习,等.甘肃北山营毛沱地区公婆泉群中玄武岩同位素定年及其地质意义[J].地球学报,2009,30(3):363-368. WANG Lishe, YANG Jianguo,WANG Yuxi,et al. Isotopic Dating of Basalt from Gongpoquan Group in Yingmaotuo Area of the Beishan Mountain, Gansu Province, and Its Geological Significance[J]. Acta Geoscientica Sinica,2009,30(3):363-368.
王立社,杨建国,谢春林,等.甘肃北山火石山哈尔根头口布花岗岩年代学、地球化学及其地质意义[J].地质学报,2009,83(3):377-387. WANG Lishe,YANG Jianguo,XIE Chunlin,et al. Geochronology and Geochemistry of Haergentoukoubu Granites in the Beishan Area,Gansu,China and Their Geological Significance[J].Geojournals,2009,83(3):377-387.
吴元保,郑永飞.锆石成因矿物学研究及其对U-Pb年龄解释的制约[J].科学通报,2004,49(16):1589-1604 杨合群, 李英, 杨建国,等.北山造山带的基本成矿特征[J].西北地质,2006,39(2):78-85. YANG Hequn,LI Ying,YANG Jianguo,et al. Main metallogenic characteristics in the Beishan Orogen[J]. Northwestern Geology, 2006,39(2):78-95.
杨合群,李英,李文明,等.北山成矿构造背景概论[J].西北地质,2008,41(1):22-28. YANG Hequn,LI Ying,LI Wenming,et al. General Discussion on Metallogenitic Tectonic Setting of Beishan Mountain, Northwestern China[J]. Northwestern Geology,2008,41(1):22-28.
杨合群,李英,赵国斌,等.北山蛇绿岩特征及构造属性[J].西北地质,2010a,43(1):26-36. YANG Hequn,LI Ying,ZHAO Guobin,et al. Character and Structural Attribute of the Beishan Ophiolite[J]. Northwestern Geology,2010a,43(1):26-36.
左国朝,何国琦.北山板块构造及成矿规律[M].北京:北京大学出版社,1990 ZUO Guochao,He guoqi. Plate Tectonics and Metallogenic Regularities in Beishan,China[M]. Beijing:Peking University Press,1990,6-167.
左国朝,李茂松.甘蒙北山地区早古生代岩石圈形成和演化[M].兰州:甘肃科学技术出版社,1996. ZUO Guochao, LI Maosong. Fomation and Evolution of the Early Paleozoic Lithosphere in the Beishan Area, Gansu-Inner Mongolia, China[M]. Lanzhou:Gansu Science and Technology Press,1996.
左国朝,刘春燕,白万成,等.北山泥盆纪碰撞造山火山-磨拉石地质构造及地球化学特征[J].甘肃地质学报,1995,4(1):35-43. ZUO Guochao,LIU Chunyan,BAI Wancheng,et al. Volcano-Molasse Geological Structure and Geochemical Signature in Devonian Period Collision Orogenic in Beishan, Gansu-Inmongolia[J]. Acta Geologica Gansu,1995,4(1):35-43.
左国朝,刘义科,刘春燕.甘新蒙北山地区构造格局及演化[J].甘肃地质学报,2003,12(1):1-15. ZUO Guochao,LIU Yike,LIU Chunyan. Framework and Evolution of the Tectonic Structure in Beishan Area Across Gansu Province, Xinjiang Autonomous Region and Inner Mongolia Autonomous Region[J]. Acta Geologica Gansu,2003,12(1):1-15.
BARTH M G,MCDONOUGH W F,RNDNICK R I. Traching the budget of Nb and Ta in the continental crust[J].Chemical Geology,2000,165(3-4):197-213.
BELOUSOVA E A,GRIFFIN W L,O'EILLY S Y,et al.Igneous zircon:trace element composition as an indicator of source rock type[J]. Contributions to Mineralogy and Petrology,2002,143:602-622.
CLEMENS,J.D.,HOLLOWAY J.R.,WHITE A.J.R. Origin of an A-type granit:experimental constraints, American[J].Mineralogist,1986,7:317-324.
COLLINS W J,BEAMS S D,WHITER A J R. Nature andorigin of A-type granites with particular reference to southeastern Australia.Contrib[J].Mineral.Petrol.,1982.80:189-200.
EBY G N.Chemical subdivision of the A-type grantitoids:Petrogenetic and tectonic implications[J].Geology,1992.20:641-644.
GREEN T H. Significance of Nb/Ta as an indicator of geochemical processes in the crust-mantle system[J]. Chemical Geology,1995. 120(3-4):347-359.
MILLER C F, MCDOWELL S M, MAPES R W. Hot and cold granites Implications of zircon saturation temperatures andpreservation of inheritance[J]. Geology,2003,31 (6):529-532.
RUDNICK R L,FOUNTAIN D M. Nature and composition of the continental crust:A lower crustal perspective[J],Rev.Geophy.,1995,33:267-309.
SONG D F,XIAO W J,HAN C M,et al. Progressive accretionary tectonics of the Beishan orogenic collage,southernAltaids:Insights from zircon U-Pb and Hf isotopic data of high-grade complexes[J]. Precambrian Research,2013,227:368-388.
TAYLOR S R and MCLENAN S M. The continental crust:Its composition and evolution[J]. The Journal of Geology,1985,94(4):91-92.
WATSON E B and HARRISON T M. Zircon saturation revisited:Temperature and composition effects in a variety of crustal magma types[J]. Earth and Planetary Science Letters,1983,64(2):295-304.
XIAO W J,MAO Q G,WINDLEY B F et al. Paleozoic multiple accretionary and collisional processes of the Beishanorogenic collage[J]. American Journal of Science,2010,310 (10):1553-1594.
计量
- 文章访问数: 2665
- HTML全文浏览量: 0
- PDF下载量: 2447
下载:
