Zircon U-Pb Dating, Geochemical Characteristics of the Gneissic Granite from North Qinling Terrain in Tongbai Area and their Geological Significance
-
摘要: 对桐柏地区北秦岭地体中侵入秦岭岩群的2个片麻状花岗岩体进行了锆石年代学和岩石地球化学研究。新庄岩体的主要岩性为片麻状白云母二长花岗岩，保水寺岩体的主要岩性为片麻状二长花岗岩，两者均具糜棱岩化。LA-MC-ICP-MS锆石U-Pb测年结果（429±3） Ma （MSWD=0.12，n=9）和（445±3） Ma （MSWD=1.02，n=16）分别代表其形成年龄，均形成于志留纪。两者均具有高硅、高铝、低镁、低铁的特点，属于高钾钙碱性系列；稀土元素总量较低，LREE相对富集，HREE相对亏损，Eu负异常中等；富集大离子亲石元素Rb、Ba、U，亏损高场强元素Nb、Ta及P、Ti。新庄片麻状花岗岩为强过铝质S型花岗岩；保水寺片麻状花岗岩为弱过铝质I型花岗岩，重稀土元素Y、Yb、Lu明显亏损。根据有关岩体的形成年龄及与围岩的接触关系，限定了桐柏地区秦岭岩群麻粒岩相变质时限为498~488 Ma，角闪岩相退变质时限在488~428 Ma，区域糜棱岩化作用发生在428 Ma之后。保水寺岩体形成于岛弧环境，其形成与古特提斯洋（商丹洋）的向北俯冲有关；新庄岩体形成于碰撞环境，其形成与桐柏地区早古生代末发生的弧陆碰撞事件有关。Abstract: The zircon geochronology and geochemistry of two gneissic granite masses intruded into Qinling group-complex in North Qinling terrain, Tongbai area have been studied in this paper. The main lithology of Xinzhuang granite mass is gneissic talc monzonitic granite, while the ones of Baoshuisi granite mass is monzonitic granite. Both of them have experienced mylonitization. The LA-MC-ICP-MS Zircon U-Pb dating has obtained the ages of (429±3) Ma (MSWD=0.12, n=9) and (445±3) Ma (MSWD=1.02, n=16), which represent the emplacement ages of these two rock mass, that is they were formed in Silurian period. The geochemistry analysis show that both granites are characterized by high Si and Al, low Mg and Fe, and they belong to high-K calc-alkaline series. Their REEs are relatively low, with relatively enriched LREE, depleted HREE and medium-negative Eu anomaly. In addition, these rocks are enriched in LILE (such as Rb, Ba, U), but depleted in HFSE (such as Nb, Ta), P and Ti. The Xinzhuang gneissic granite belongs to strongly peraluminous S-type granite, while the Baoshuisi gneissic granite belongs to weak peraluminous I type granite, with obviously depleted HREE (Y, Yb, Lu). Based on the formation age of related rock mass and the contact relation with wall rock, it's limited that the granulite-facies metamorphism in Qinling group-complex took place at ca. 498~488 Ma, the amphibolite-facies retrogressive metamorphism occurred at ca. 488~428 Ma, and the regional mylonitization take place after 428 Ma. The Baoshuisi granite mass was formed in island arc environment, which is related to the northward subduction of Paleo-Tethys Ocean (Shangdan Ocean). The Xinzhuang granite mass was formed in impact environment, which is related to the arc-continent collision event at the end of the Early Paleozoic in Tongbai area.
-
Keywords:
- Tongbai area /
- North Qinling terrain /
- gneissic granite /
- zircon U-Pb dating /
- oceanic subduction
-
-
冯胜斌,周洪瑞,燕长海,等.东秦岭二郎坪群硅质岩地球化学特征及其沉积环境意义[J].现代地质,2007,21(4):675-682. FENG Shengbin, ZHOU Hongrui, YAN Changhai, et al. The geochemical characteristics of cherts of Erlangping group in east Qingling and their sedimentary environment importance[J]. Geoscience, 2007, 21(4):675-682.
江思宏,聂凤军,方东会,等.河南桐柏围山城地区侵入岩年代学与地球化学特征[J].地质学报,2009,83(7):1011-1029. JIANG Sihong, NIE Fengjun, FANG Huidong, et al. Geochronology and geochemical features of the main intrusive rocks in the Weishancheng area, Tongbai County, Henan[J]. Acta Geologica Sinica, 2009, 83(7):1011-1029.
李怀坤,耿建珍,郝爽,等.用激光烧蚀多接受器等离子体质谱仪(LA-MC-ICP MS)测定锆石U-Pb同位素年龄的研究[J].矿物学报,2009,29(增刊):600-601. LI Huaikun, GENG Jianzhen, HAO Shuang, et al. Study on zircon U-Pb dating by LA-ICP MS[J]. Acta Mineralogica Sinica, 2009, 29(sl):600-601.
刘丙祥.北秦岭地体东段岩浆作用与地壳演化[D].合肥:中国科学技术大学,2014. LIU Bingxiang. Magmatism and crustal evolution in the eastern North Qinling Terrain[D]. Hefei:University of Science and Technology of China, 2014.
刘晓春,李三忠,江博明.桐柏-红安造山带的构造演化:从大洋俯冲/增生到陆陆碰撞[J].中国科学:地球科学,2015,45(8):1088-1108. LIU Xiaochun, LI Sanzhong, JAHN B M. Tectonic evolution of the Tongbai-Hong'an orogen in central China:From oceanic subduction/accretion to continent-continent collision[J]. Science China:Earth Sciences, 2015, 58(9):1477-1496.
陆松年,李怀坤,陈志宏,等.秦岭中一新元古代地质演化及对Rodina超级大陆事件的响应[M].北京:地质出版社,2003. LU Songnian, LI Huaikun, CHEN Zhihong, et al. Meso-neoproterozoic geological evolutio in the Qinlin Orogeny and its response to the supercontinental events of Rodinia[M]. Beijing:Geological Publishing House, 2003.
曲玮,刘晓春,胡娟,等.桐柏地区秦岭岩群中碱性脉岩的锆石U-Pb年龄:对麻粒岩相变质时代的约束[J].岩石学报,2013,29(9):3080-3086. QU Wei, LIU Xiaochun, HU Juan, et al. Zircon U-Pb ages of alkaline dykes from the Qinling Group in the Tongbai are, central China:Constraints on the timing of granulite-facies metamorphism[J]. Acta Petrologica Sinica, 2013, 29(9):3080-3086.
任留东,李崇,王彦斌,等.桐柏秦岭岩群的两类变质作用[J].岩石学报,2016,32(6):1596-1610. REN Liudong, LI Cong, WANG Yanbin, et al. Two types of metamorphism in the Qinling Complex, Tongbai area, Henan Province[J]. Acta Petrologica Sinica, 2016, 32(6):1596-1610.
王浩.东秦岭-桐柏造山带新元古代-早古生代不同阶段演化的变质和岩浆作用[D].武汉:中国地质大学,2014. WANG Hao. Neoproterozoic-Early Paleozoic Metamorphism and Magmatism during the Multistage Evolution of the Eastern Qinling-Tongbai Orogenic Belt[D]. Wuhan:China University of Geosciences, 2014.
王涛,王晓霞,田伟,等.北秦岭古生代花岗岩组合、岩浆时空演变及其对造山作用的启示[J].中国科学(D辑:地球科学),2009,39(7):949-971. WANG Tao, WANG Xiaoxia, TIAN Wei, et al. North Qinling Paleozoic granite associations and their variation in space and time:Implications for orogenic processes in the orogens of central China[J]. Sci China Ser D-Earth Sci, 2009, 39(7):949-971.
吴元保,郑永飞.华北陆块古生代南向增生与秦岭-桐柏-红安造山带构造演化[J].科学通报,2013,58(23):2246-2250. WU Yuanbao, ZHENG Yongfei. Southward accretion of the North China Block and the tectonic evolution of the Qinling-Tongbai-Hong'an orogenic belt[J]. China Sci Bull, 2013, 58(23):2246-2250.
向华,张利,钟增球,等.北桐柏地区镁铁质麻粒岩锆石U-Pb年代学及变质作用[J].岩石学报,2009,25(2):348-358. XIANG Hua, ZHANG Li, ZHONG Zengqiu, et al. Zircon U-Pb geochronology and metamorphism of mafic granulite from north Tongbai, central China[J]. Acta Petrologica Sinica, 2009, 25(2):348-358.
向华,钟增球,李晔,等.北秦岭造山带早古生代多期变质与深熔作用:锆石U-Pb年代学证据[J].岩石学报,2014,30(8):2421-2434. XIANG Hua, ZHONG Zengqiu, LI Ye, et al. Early Paleozoic polymetamorphism and anatexis in the North Qinling orogen:Evidence from U-Pb zircon geochronology[J]. Acta Petrologica Sinica, 2014, 30(8):2421-2434.
张本仁,张宏飞,赵志丹,等.东秦岭及邻区壳、幔地球化学分区和演化及其大地构造意义[J].中国科学(D辑),1996,26(3):201-208. ZHANG Benren, ZHANG Hongfei, ZHAO Zhidan, et al. Geochemical subdivision and evolution of the Lithosphere in East Qinling and adjacent regions:Implications for tectonics[J]. Science in China(Series D), 1996, 26(3):201-208.
张本仁,韩吟文,许继锋,等.北秦岭新元古代前属于扬子板块的地球化学证据[J].高校地质学报,1998,4(4):369-382. ZHANG Benren, HAN Yinwen, XU Jifeng et al. Geochemical evidence for north Qinling being a part of Yangtze plate prior to the Neoproterozoic[J]. Geological Journal of China Universities, 1998, 4(4):369-382.
张国伟,张本仁,袁学诚,等.秦岭造山带与大陆动力学[M]. 北京:科学出版社,2001. ZHANG Guowei, ZHANG Benren, YUAN Xuecheng, et al. Qingling orogenic belt and continental dynamics[M]. Beijing:Science Press, 2001.
张旗,王焰,李承东,等.花岗岩的Sr-Yb分类及其地质意义[J].岩石学报,2006,22(9):2249-2269. ZHANG Qi, WANG Yan, LI Chengdong, et al. Granite classification on the basis of Sr and Yb contents and its implications[J]. Acta Petrologica Sinica, 2006, 22(9):2249-2269.
张宗恒,曾宪友,陈曾武,等.桐柏县幅(I-49-131-D)1:5万区域地质调查报告[R].郑州:河南省地质矿产厅,1994. 赵姣,陈丹玲,谭清海,等.北秦岭东段二郎坪群火山岩锆石的LA-ICP-MS U-Pb定年及其地质意义[J].地学前缘,2012,19(4):118-125. ZHANG Jiao, CHEN Danling, TAN Qinghai, et al. Zircon LA-ICP-MS U-Pb dating of basic volcanics from Erlangping Group of the North Qinling, eastern Qinling Mountains and its geological implications[J]. Earth Science Frontiers, 2012, 19(4):118-125.
赵如意,李卫红,姜常义,等.东秦岭丹凤地区黄龙庙二长花岗岩LA-ICP-MS锆石U-Pb年龄、岩石地球化学特征及其地质意义[J].地质论评,2014,60(5):1123-1132. ZHAO Ruyi, LI Weihong, JIANG Changyi, et al. The LA-ICP-MS Zircon U-Pb dating, petro-geochemical characteristics of Huanglongmiao monzogranite in Danfeng Area in Eastern Qingling Mountains and Their Geological Significance[J]. Geological Review, 2014, 60(5):1123-1132.
ANDERSON T. Correction of common lead in U-Pb analyses that do not report 204Pb[J]. Chemical Geology, 2002, 192(1-2):59-79.
BELOUSOVA E A, GRIFFIN W L, O'REILLY S Y, et al. Igneous zircon:Trace element composition as an indicator of source rock type[J]. Contributions to Mineralogy and Petrology, 2002, 143(5):602-622.
DONG Y P, ZHANG G W, Neubauer F, et al. 2011. Tectonic evolution of the Qinling orogen, China:Review and synthesis[J]. Journal Asian Earth Sciences, 2011, 41(3):213-237.
HACKER B R, RATSCHBACHER L, LIOU J G. Subduction, collision and exhumation in the ultrahigh-pressure Qinling-Dabie orogen[J]. Geological Society London Special Publications, 2004, 226(1):157-175.
JACKSON S E, PEARSON N J, GRIFFIN W L, et al. The application of laser ablation-inductinvely coupled plasma-mass spectrometry to in situ U-Pb zircon geochronology[J]. Chemical Geology, 2004, 211(1):47-69.
KRÖNER A, ZHANG G W, SUN Y. Granulites in the Tongbai area, Qinling belt, China:Geochemistry, petrology, single zircon geochronology, and implications for the tectonic evolution of eastern Asia[J]. Tectonics, 1993, 12(1):245-255.
LIU X C, JAHN B M, HU J, et al. Metamorphic patterns and SHRIMP zircon ages of medium-to-high grade rocks from the Tongbai orogen, central China:implications for multiple accretion/collision processes prior to terminal continental collision[J]. Journal of Metamorphic Geology, 2011, 29(9):979-1002.
LIU X C, JAHN B M, LI S Z, et al. U-Pb zircon age and geochemical constraints on tectonic evolution of the Paleozoic accretionary orogenic system in the Tongbai orogen, central China[J]. Tectonophysics, 2013, 599(4):67-88.
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-Pb dating, Hf isotopes and trace elements in zircons from mantle xenoliths[J]. Journal of Petrology, 2009, 51(1-2):537-571.
LUDWIG K R. Isoplot/Ex version 3.00. A geochronological toolkit for Microsoft Excel[J]. Berkeley Geochronology Center Special Publication, 2003, 4:1-70.
MAITRE R W L. A classification of igneous rocks and glossary of terms:recommendations of the international union of geological sciences subcommission on the systematics of igneous rocks[M]. Blackwell Scientific Publications, 1989.
MANIAR P, PICCOLI P. Tectonic discrimination of granitoids[J]. Geological Society of America Bulletin, 1989, 101(5):635-643.
PECCERILLO A, TAYLOR S R. Geochemistry of Eocene calcalkaline volcanic rocks from the Kastamonu area, northern Turkey[J]. Contributions to Mineralogy and Petrology, 1976, 58(1):63-81.
RUBATTO D. Zircon trace element geochemistry:Partitioning with garnet and the link between U-Pb ages and metamorphism[J]. Chemical Geology, 2002, 184(1):123-138.
SUN S S, MCDONOUGH W F. Chemical and isotopic systematics of oceanic basalts:implications for mantle composition and processes[J]. Geological Society London Special Publications, 1989, 42(1):313-345.
WANG H, WU Y B, GAO S, et al. Silurian granulite facies metamorphism, and coeval magmatism and crustal growth in the Tongbai orogen, central China[J]. Lithos, 2011, 125(1-2):249-271.
XIANG H, ZHANG L, ZHONG Z Q, et al. Ultrahigh-temperature metamorphism and anticlockwise P-T-t path of Paleozoic granulites from north Qinling-Tongbai orogen, central China[J]. Gondwana Research, 2012, 21(2-3):559-576.
ZHAI X M, DAY H W, Hacker B R, et al. Paleozoic metamorphism in the Qinling orogen, Tongbai Mountains, central China[J]. Geology, 1998, 26(4):371-374.
ZHANG H F, GAO S, ZHANG L, et al. Granulite genesis and tectonic evolution in Tongbai area:Single zircon evaporation ages and Nd isotopic geochemistry[J]. Journal of China University of Geosciences, 1998, 9(3):31-36.
计量
- 文章访问数: 2058
- HTML全文浏览量: 0
- PDF下载量: 2069
下载:
