Confirmation and Geological Significance of Early Ordovician Adakite in Embouchure Area of the Eastern Segment of the Lajishan Mixed Belt
-
摘要: 拉脊山混杂带东段峡门地区侵入岩可进一步解体为英云闪长岩和花岗闪长岩。通过LA-ICP-MS锆石U-Pb同位素测年，获得英云闪长岩锆石U-Pb年龄为（480.7±1.9）Ma（MSWD=0.80），代表岩体侵位时代为早奥陶世。主量元素特征表明岩石具高硅（SiO2=59.10%~63.45%）、高铝（Al2O3=15.40%~16.19%）、富钠贫钾（Na2O/K2O=1.41~2.03）的特征，属于钙碱性-高钾钙碱性系列岩石。稀土元素球粒陨石标准化配分模式图上呈轻稀土富集（ΣLREE=148.22×10-6~173.46×10-6）、重稀土亏损（ΣHREE=10.04×10-6~14.40×10-6）的右倾型曲线，显示轻微Eu负异常（δEu=0.92~0.96）。岩石明显富集Rb、Ba、Th等大离子亲石元素，亏损Nb、Ta、Ti、P等高场强元素，同时形成Ta、P、Ti均亏损的"TNT"谷，显示出弧花岗岩特征。岩石具高Sr（591.9×10-6~922.9×10-6）、低Y（12.44×10-6~18.79×10-6）和低Yb（1.24×10-6~1.90×10-6）特点，具有较高的Sr/Y（34.85~55.76）值，与典型的埃达克岩地球化学特征一致。结合区域资料综合研究认为，峡门早奥陶世埃达克岩源于俯冲板片流体交代地幔楔诱发下地壳富含角闪岩相的基性玄武质岩石部分熔融，形成于俯冲、消减作用下的活动大陆边缘火山弧环境，说明该时期拉脊山洋盆在峡门地区已处于板块碰撞前期阶段。Abstract: The intrusive rocks in embouchure area of the eastern segment of the Lajishan mixed belt can be further disintegrated into Yingyun diorite and granodiorite. The zircon U-Pb isotopic dating is carried out by LA-ICP-MS. The zircon U-Pb age of Yingyun diorite is (480.7±1.9) Ma (MSWD=0.80), which indicates that the emplacement age of rock mass is early Ordovician.The characteristics of principal elements show that the rocks have high silicon (SiO2=59.10%-63.45%), high aluminum (Al2O3=15.40%-16.19%), rich sodium and little potassium (Na2O/K2O=1.41-2.03). The rocks belong to calc-alkaline-high-potassium calc-alkaline series rocks. The standardized partition pattern diagram of rare earth element meteorite shows the right dip curve of light rare earth enrichment (ΣLREE=148.22×10-6-173.46×10-6) and heavy rare earth loss (ΣHREE=10.04×10-6-14.40×10-6), with the negative anomaly of slight Eu (δEu=0.92-0.96). The rocks are obviously enriched in large ion lithophile elements such as Rb,Ba,Th and deficient in high field strength elements such as Nb,Ta,Ti,P. At the same time, the ‘TNT’ valley with loss of Ta,P,Ti is formed, which shows the characteristics of arc granite. The rock has the characteristics of high Sr (591.9×10-6-922.9×10-6), low Y (12.44×10-6-18.79×10-6) and low Yb (1.24×10-6-1.90×10-6), and a high ratio of Sr/Y (34.85×55.76). The geochemical characteristics are consistent with those of the typical adakite. Combined with the comprehensive study of the regional data, it is considered that the early Ordovician Adakite in embouchure area was originated from the partial melting of basement basaltic rocks which was induced by subduction plate fluid metasomatic mantle wedges and rich in hornblende facies, and was formed under the action of subduction and consumption of the volcanic arc environment of the active continental margin. This indicates that the oceanic basin of Laji Mountain was already in the early stage of plate collision in embouchure area during this period.
-
Key words:
- geochemistry /
- zircon U-Pb age /
- Early Ordovician /
- Adakite /
- Lajishan mixed zone /
- Xiamen area
-
-
白旭东, 杨波, 赵忠国, 等. 青海南祁连晚奥陶世火山岩LA-MC-ICPMS锆石U-Pb年龄及其地球化学特征[J]. 西北地质, 2018, 51(01):125-136.
BAI Xudong, YANG Bo, ZHAO Zhongguo, et al. LA-MC-ICPMS Zircon U-Pb Dating and Geochemical Characteristics of Late Ordovician Volcanic Rocks in Southern Qilan Mountains, Qinghai Province[J].Northwestern Geology, 2018, 51(01):125-136.
冯益民, 曹宣铎, 张二朋, 等.西秦岭造山带结构造山过程及动力学[A]."九五"全国地质科技重要成果学术交流会[C], 2000,86-90.
FENG Yimin, CAO Xuanduo, ZHANG Erpeng, et al. Structural orogeny process and dynamics of the West Qinling orogenic belt[A].National academic Exchange Conference on important achievements in Geoscience and Science and Technology during the Ninth five-year Plan[C],2000,86-90(in Chinese with English abstract).
付长垒, 闫臻, 郭现轻, 等. 拉脊山口蛇绿混杂岩中辉绿岩的地球化学特征及SHRIMP锆石U-Pb年龄[J]. 岩石学报, 2014, 30(6):1695-1706.
FU Changlei, YAN Zhen, GUO Xianqing, et al. Geochemistry and SHRIMP zircon U-Pb age of diabases in the Lajishankou ophiolitic mélange, South Qilian terrane[J]. Acta Petrologica Sinica, 2014, 30(6):1695-1706.
付长垒,闫臻.拉脊山蛇绿混杂带结构组成、形成时代与形成过程[J].地球学报, 2017, 38(s1):29-32.
FU Changlei, YAN Zhen. The Composition, Age and Tectonic Setting of Lajishan Ophiolitc Mélange[J].Acta Geoscientica Sinica. 2017, 38(s1):29-32.
付长垒,闫臻,王宗起,等.南祁连拉脊山口增生楔的结构与组成特征[J]. 岩石学报, 2018a, 34(7):2049-2064.
FU Changlei, YAN Zhen, WANG Zongqi, et al. Texture and composition of the Lajishankou accretionary wedge of the South Qilian belt, NW China[J]. Acta Petrologica Sinica, 34(7):2018a, 2049-2064(in Chinese with English abstract)
高亮. 青海拉脊山混杂带埃达克岩的发现及其地质意义[D].西宁:青海大学, 2018.
GAO Liang. The Discovery and Geological Significance of Adakites in th Lajishan mixed belt in Qinhai[D]. Xining:Qinghai University, 2018.
高永丰, 侯增谦, 魏瑞华. 冈底斯晚第三纪斑岩的岩石学、地球化学及其地球动力学意义[J]. 岩石学报, 2003, 19(3):418-428.
GAO Yongfeng, HOU Zengqian, WEI Ruihua. Neogene porphyries from gangdese:petrological geochemical characteristics and geodynamic significances[J]. Acta Petrologaca Sinica, 2003, 19(3):418-428.
国显正, 贾群子, 李金超, 等. 2019. 东昆仑哈日扎花岗闪长岩形成时代、地球化学特征及其构造意义[J]. 地质力学学报, 25(2):286-300.
GUO Xianzheng, JIA Qunzi, LI Jinchao, et al. The forming age and geochemistry characteristics of the gtanodiorites in Harizha, East Kunlun and its tectonic significance[J]. Journal of Geomechanics, 2019, 25(2):286-300.
黄万堂,王玉玺,李通国,等. 敦煌地块南缘小红山埃达克岩的年代学、地球化学特征及地球动力学意义[J].地质学报, 2018, 92(12):2437-2452.
HUANG Wantang, WANG Yuxi, LI Tongguo, et al. Geochronology and Geochemistry of Adakite in Xiaohongshan, Southwestern Margin of the Dunhuang Block and their Geodynamic Implications[J].Acta Geologica Sinica, 2018, 92(12):2437-2452.
李碧乐, 孙丰月, 于晓飞, 等. 东昆中隆起带东段闪长岩U-Pb年代学和岩石地球化学研究[J]. 岩石学报, 2012, 28(4):1163-1172.
LI Bile, SUN Fengyue, YU Xiaofei, et al. U-Pb dating and geochemistry of diorite in the eastern section from eastern Kunlun middle uplifted basement and granitic belt[J].Acta Petrologica Sinica, 2012, 28(4):1163-1172.
史长义,鄢明才,刘崇民, 等.中国花岗岩类化学元素丰度及特征[J].地球化学,2005,34(5):470-482.
SHI Changyi, YAN Mingcai, LIU Chongmin, et al. Abundances of chemical elements in granitoids of China and their characteristics[J]. Geochimica, 2005, 34(5):470-482.
王二七, 张旗, BURCHFIEL C B.青海拉鸡山:一个多阶段抬升的构造窗[J]. 地质科学, 2000, 35(4):493-500.
WANG Erqi, ZHANG Qi, BURCHFIEL C B. The Lajishan Faule Belt in Qinghai province:A multi-staged uplifting structural window[J]. Chinese Journal of Geology, 2000, 35(4):493-500.
王涛,马振慧,王宗起,等. 中祁连拉脊山早古生代沉积岩源区和时代限定[J].地质学报, 2016, 90(9):2316-2333.
WANG Tao, WANG Zongqi, YAN Zhen, et al. Geochronological and Geochemical evidence of amphibolite from the Hualong Group, northwest China:Implication for the early Paleozoic accretionary tectonics of the Central Qilian belt[J]. Lithos, 2016, 248-251:12-21.
吴福元, 李献华, 杨进辉, 等. 花岗岩成因研究的若干问题[J]. 岩石学报, 2007, 23(6):1217-1238
WU Fuyuan, LI Xianhua, YANG Jinhui, et al. Discussions on the petrogenesis of granites[J]. Acta Petrologica Sinica, 2007, 23(6):1217-1238.
吴福元, 刘志超, 刘小驰, 等.喜马拉雅淡色花岗岩[J]. 岩石学报, 2015, 31(1):1-36.
WU Fuyuan, LIU Zhichao, LIU Xiaochi, et al. Himalayan leucogranite:Petrogenesis and implications to orogenesis and plateau uplift[J]. Acta Petrologica Sinica, 2015, 31(1):1-36.
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.
WU Yuanbao, ZHEN Yongfei. Zircon Mineralogy and its constraints on interpretion of U-Pb Age[J]. Chinese Science Bulletin, 2004, 49(16):1589-1604.
肖庆辉, 邓晋福, 马大铨. 花岗岩研究思维与方法[M].北京:地质出版社, 2002, 53-63.
XIAO Qinghui, DENG Jinfu, MA Dashuan. Research idea and means of granite[M]. Beijing:Publication of Geology, 2002, 53-63.
肖序常, 陈国铭, 朱志直. 祁连山古蛇绿岩带的地质构造意义[J]. 地质学报, 1987, (4):31-88.
XIAO Xuchang, CHEN Guoming, ZHU Zhizhi. Geological and tectonic significance of paleo-ophiolite belt in Qilian Mountains[J]. Acta Geological Sinica, 1987, (4):31-88.
夏林圻, 李向民, 余吉远, 等. 祁连山新元古代中-晚期至早古生代火山作用与构造演化[J].中国地质, 2016, 43(04):1087-1138.
XIA Linqi, LI Xiangmin, YU Jiyuan, et al. Mid-Late Neoproterozoic to Early Paleozoic volcanism and tectonic evolution of the Qilian Mountain[J]. Geology in China, 2016, 43(4):1087-1138.
杨贺. 中祁连东段早古生代岩浆侵入作用及其深部过程[D].北京:中国地质大学(北京), 2016.
YANG He. Early Paleozoic Intrusive Magmatism and Geodynamic Processes in the Eastern Segment of the Central Qilian[D].Beijiang:China University of Geosciences(Beijing), 2016.
闫义, 林舸, 李自安. 利用锆石形态、成分组成及年龄分析进行沉积物源区示踪的综合研究[J]. 大地构造与成矿学, 2003, 27(2):184-190.
YAN Yi, LIN Ge, LI Zian. Provenance Tracing of Sediments by Means of Synthetic Study of Shape, Composition and Chronology of Zircon[J]. Geotectonica et Metallogenia, 2003, 27(2):184-190.
闫臻, 王宗起, 李继亮, 等. 西秦岭楔的构造属性及其增生造山过程[J]. 岩石学报, 2012, (6):1808-1828.
YAN Zhen, WANG Zongqi, LI Jiliang, et al. Tectonic settings and accretionary orogenesis of the West Qinling Terrane, northeastern margin of the Tibet Plateau[J]. Acta Petrologica Sinica, 2012, 28(6):1808-1828.
曾广策, 邱家骧, 朱云海. 拉鸡山造山带的蛇绿岩套及古构造环境[J]. 青海地质, 1997,(1):1-6.
ZENG Guangce, QIU Jiaxiang, ZHU Yunhai. Ophiolotic suite of Lajishan orogenic belt and its Paleoteconic setting[J]. Qinghai Geology, 1997, (1):1-6.
左国朝, 张淑玲. 祁连地区蛇绿岩带划分及其构造意义[A]. 蛇绿岩与地球动力学研讨会[C],1996, 129-133.
ZUO Guochao, ZHANG Shuling. Divesion of ophiolite zones and their tectonic significance in Qilian area[A]. Seminar on Ophiolite and Geodynamics[C],1996, 129-133.
左国朝, 李志林. 青海拉鸡山构造带是裂谷还是构造窗——与王二七研究员商榷[J]. 地质论评, 2001, 47(6):561-566.
ZUO Guochao, LI Zhilin. Lajishan Tectonic Zone of Qinghai Province:Rift or Tectonic Window?——To Discuss with Prof. Wang Erqi[J]. Geological Review, 2001, 47(6):561-566.
张国伟, 柳小明. 关于"中央造山带"几个问题的思考[J]. 地球科学, 1998, 23(05):9-14.
ZHANG Guowei, LIU Xiaoming. Thoughts on several problems of "Central orogenic Belt"[J]. Earth Science, 1998, 23(05):9-14.
赵宏刚,梁积伟,王驹,等. 甘肃北山算井子埃达克质花岗岩年代学、地球化学特征及其构造意义[J].地质学报, 2019, 93(2):329-352.
ZHAO Honggang, LIANG Jiwei, WANG Ju, et al. Geochronology and geochemical characteristics of the Suanjingzi adakitic granites in the Beishan Mountains, Gansu Province,China, and their tectonic significance[J]. Acta Geologica Sinica, 2019, 93(2):329-352.
张建新, 许志琴, 陈文, 等. 北祁连中段俯冲-增生杂岩/火山弧的时代探讨[J]. 岩石矿物学杂志, 1997, (2):112-119.
ZHANG Jianxin, XU Zhiqin, CHEN Wen, et al. A tentative discussion on the ages of the subduction-Accretionary comliex/Volcanic Arcs in the Middle Sector of North Qilian Mountain[J]. Acta Petrologica ET Mineralogica, 1997, (2):112-119.
张旗, 王焰, 王元龙. 埃达克岩与构造环境[J]. 大地构造与成矿学, 2003, 27(02):101-108.
ZHANG Qi, WANG Yan, WANG Yuanlong. On the relationship between adakite and its tectonic setting[J]. Geotectonica et Metallogenia, 2003, 27(02):101-108.
张旗, 冉皞, 李承东. A型花岗岩的实质是什么?[J]. 岩石矿物学杂志, 2012, 31(4):621-626.
ZHANG Qi, RAN Hao, LI Chengdong. A-type granite:what is the essence?[J]. Acta Petrologica Et Mineralogica, 2012, 31(4):621-626(in Chinese with English abstract).
张永明, 裴先治, 李佐臣, 等. 青海南山当家寺花岗岩体锆石U-Pb年代学、地球化学及其地质意义[J]. 地质学报, 2017, 91(3):523-541.
ZHANG Yongming, PEI Xianzhi, LI Zuochen, et al. LA-ICP-MS Zircon U-Pb Dating and Geochemistry of the Dangjiasi Granitic Complex in the Qinghai Nanshan Tectonic Zone, and Its Geological Implications[J].Acta Geologica Sinica, 2017, 91(3):523-541.
张新远, 欧阳光文, 王春涛, 等. 拉脊山东段峡门地区新元古代花岗闪长岩体锆石U-Pb年龄及地质意义[J]. 中国锰业, 2018a, 36(05):94-97.
ZHANG Xinyuan, OUYANG Guangwen, WANG Chuntao, et al. Zircon U-Pb age and geological significance of Neoproterozoic granodiorite in Xiamen area, eastern section of Lajishan.[J]. China's Manganese industry, 2018a, 36(05):94-97.
张新远, 王春涛, 欧阳光文, 等. 南祁连敖果吞乌兰侵入岩锆石U-Pb年龄及其地质意义[J].地球科学与环境学报, 2018b, 40(05):46-562.
ZHANG Xinyuan, WANG Chuntao, OUYANG Guangwen, et al. Zircon U-Pb Ages and Their Geological Significance of Aoguotunwulan Pluton in South Qilian, China[J].Journal of Earth Sciences and Environment, 2018b, 40(05):546-562.
钟林汐.青海拉脊山中酸性侵入岩的地球化学特征、成岩时代及构造意义[D]. 北京:中国地质大学(北京), 2015.
ZHONG Linxi. Geochemical characteristics, diagenetic ages and tectonic significances of the intermediate-felsic intrusive rocks in Qinghai Lajishan mountains[D]. Beijiang:China University of Geosciences(Beijing), 2015.
ALLEGRE.C.J, MINSTER J F. Quantitative models of trace element behavior in magmatic processes[J]. Earth and Planetary Science Letters, 1978, 38(1):0-25.
BATCHELOR R A, BOWDEN P. Petrogenetic interpretation of granitoid rock series using multicationic parameters[J]. Chem. Geol. 1985, 48(1-4):0-55.
BEA F, Arzamastsev A, Montero P, et al. Anomalous alkaline rocks of Soustov, Kola:evidence of mantle-derived metasomatic fluids affecting crustal materials[J]. Contributions to Mineralogy and Petrology, 2001, 140(5):554-566.
BOYNTON W V. Cosmochemistry of the RareEarth Elements:Meteoric Studies[J]. Rare Earth Element Geochemistry, 1984,(2):63-114.
CHAPPELL B W, WHITE A J R. Two contrasting granite types:25 years later[J]. Australian Journal of Earth Sciences, 2001, 48(4):489-499.
CONDIE K C. Geochemical changes in baslts and andesites across the Archean-Proterozoic boundary:Identification and significance[J]. Lithos, 1989, 23(1-2):1-18.
DEFANT M J, DRUMMOND M S. Derivation of some modern arc magmas by melting of young subducted lithosphere[J]. Nature, 1990, 347(6294):662-665.
DEFANT M J, XU Jifeng, KEPEZHINSKAS P, et al. Adalkite:Some variations on a theme[J]. Acta Petrologica Sinica, 2002, 18(2):129-142.
ROCHE H D L, LETERRIER J, GRANDCLAUDE P, et al. A classification of volcanic and plutonic rocks using R1R2-diagram and major-element analyses-Its relationships with current nomenclature[J]. Chemical Geology, 1980, 29(1-4):0-210.
FODEN J, SOSSI P A, WAWRYK C M. Fe isotopes and the contrasting petrogenesis of A-, I- and S-type granite[J]. Lithos, 2015, 212-215:32-44.
FU Changlei, YAN Zhen, WANG Zongqi, et al. Lajishankou ophiolite complex:Implications for Paleozoic multiple accretionary and collisional events in the South Qilian belt[J]. Tectonics,2018b,37(5).
HU Jun, WANG He, MU Shenglu, et al. Geochemistry and Hf isotopic compositions of Early Paleozoic granites Nanpingxueshan from the Tianshuihai Terrane, West Kunlun:Crust Mantle Magmatism[J]. Acta Geological Sinica, 2017, 91(6):1992-1207.
IRVINE T N, BARAGRA W R A. A guide to the chemical classification of the common volcanic rocks[J]. Canadian Journal of Earth Sciences, 1971, 8(5):523-548.
LIU Yongsheng, GAO Shan, HU Zhaochu, et al. Continental and oceanic crust recy-cling-incluced melt-peridoite interactions in the Trans-North China Orogen:U-Pb dating, Hf isotopes and trace element in zir-con from mantle xenoliths[J]. Journal of Petrology, 2010, 51(1/2):537-571.
LUDWIG K R. Isoplot/Ex version 2.49.A Geochronological Toolkit for Microsoft Excel[M]. Berkeley:Berkeley Geochronology Center Special Publication No.1a,2003, 1-56.
MANIAR P D, PICCOLI P M. Tectonic Discrimination of Granitoids[J]. Geological Society of America Bulletin, 1989, 101(5):635-643.
MARTIN H. The adakitic magmas:modern analogues of Archaean granitoids[J]. Lithos, 1999, 46:411-429.
MOLLER A, O"BRIEN P J, KENNEDY A, et al. Linking growth episodes of zircon and metamorphic textures to zircon chemistry:an example from the ultrahigh-temperature granulites of Rogaland (SW Norway)[J]. Geological Society, London, Special Publications, 2003, 220(1):65-81.
MUKHERJEE S. A review on out-of-sequence deformation in the Himalaya[J]. Geological Society London Special Publications, 2015, 142(1):67-109.
O'CONNOR J. T. A classification for quartz-rich igneous rocks based on feldspar rations[M]. US Geological Survey Research, 1965, 79-84.
PATINO D A E. What do experiments tell us about the relative contributions of crust and mantle to the origin of granitic magmas?[J]In:Castro A, Femndez C, Vignereese J L, eds. Understanding granites:Intergrating new and classical techniques. Geological Society, London, Spesial Publications, 1999, 168:55-75.
PEARCE T H, GORMAN B E, BIRKETT T C. The relationship between major element chemistry and tectonic environment of basic and intermediate volcanic rocks[J]. Earth Planet.sci.lett, 1977, 36(1):121-132.
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(4):956-983.
PECCERILLO R, TAYLOR S R. Geochemistry of eocene calc-alkaline volcanic rocks from the Kastamonu area, Northern Turkey[J]. Contributions to Mineralogy & Petrology, 1976, 58(1):63-81.
ROBERTA L. Rudnick. Making continental crust[J]. Nature, 1995, 378(6557):571-578.
SUN S S, MCDONOUGH W F. Chemical and lsotopic Systematics of Oceanic Basalts:Implications for Mantle Composition and Processes[J]. Geological Society London Special Publications, 1989, 42(1):313-345.
SYLVESTER P J. Post-collisional strongly peraluminous granites[J]. Lithos, 1998, 45(1):29-44.
TAYLOR S R, MCLENNAN S M. The Continental Crust:Its Composition and Evolution. Oxford[M]. UK:Blackwell Scientfic Publications, 1985, 1-312.
VAVRA G, GEBAUER D, SCHMID R. Multiple zircon growth and recrystallization during polyphase Late Carboniferous to Triassic metamorphism in granulites of the Ivrea Zone(Southern Alps):an ion microprobe(SHRIMP)study[J]. Contributions to Mineralogy and Petrology, 1996, 122:337-358.
VAVRA G, SCHMID R, GEBAUER D. Internal morphology, habit and U-Th-Pb microanalysis of amphibole to granulite facies zircon:geochronology of the ivren zone(Southern Alps)[J]. Contributions to Mineralogy and Petrology, 1999, 134:380-404.
WANG Tao, MA Zhenhui, WANG Zongqi, et al. Constraints of the Provenance and Deposition Time of the Early Paleozoic Sedimentary Rocks in the Lajishan Area, Central Qilian[J].Acta Geologica Sinica, 2016, 90(9):2316-2333.
WHALEN J B, CURRIE K L, CHAPPELL B W. A-type granites:geochemical characteristics, discriminatuon and petrogenesis[J]. Contributions to Mineralogy and Petrology, 1987, 95:407-419.
WINCHESTER J A. Geochemical discrimination of different magma series and their differentiation products using immobile elements[J]. Chemical Geology, 1977, 20(4):325-343.
XIAO Wenjiao, WINDLEY B F, YONG Yong, et al. Early Paleozoic to Devonian multiple-accretionary model for the Qilian Shan, NW China[J]. Journal of Asian Earth Sciences, 2009, 35(3-4):0-333.
-
计量
- 文章访问数: 1304
- PDF下载数: 614
- 施引文献: 0
下载: