燕山期中国东部高原下地壳组成初探：埃达克质岩Sr、Nd同位素制约
Preliminary study on the components of the lower crust in east China Plateauduring Yanshanian Period: Constraints on Sr and Nd isotopic compositions of adakite-likerocks
-
摘要: 大陆地壳组成是地球科学家关注的课题，但困难的是如何确定深部地壳，尤其是下地壳的组成。埃达克质岩的厘定从一个方面有助于这个难题的解决。中国东部“C型”埃达克质岩（adakite-like)的地球化学性质表明其形成的深度大，熔融的温度高，为下地壳中基性麻粒岩部分熔融的产物。因此，可以尝试通过埃达克质岩的地球化学特征来反演下地壳的组成。本文的初步研究表明，中国东部埃达克质岩的Sr-Nd同位素组成有很大的变化，反映埃达克质岩熔融的源区下地壳组成有明显的不同。根据埃达克质岩石的Sr-Nd同位素组成，推测中国东部高原下地壳大体由胶东－大别、北京－辽西和下扬子（长江中下游）3个不同的块体组成。1，胶东－大别区：胶东区的下地壳以富Si,Na2O/K2O低（0．8－1．3）、Isr高（0．709－0．712）、εNd(t)低（－15－－21）和TDM高（1．9－2．1Ga)为特征；大别区的Isr值较低，可能代表了中生代时基底的特征，大体相当于该区下地壳的上限值。2，下扬子区位于扬子地块内，中生代埃达克质岩的Sr初始值，εNd和TDM变化大，说明元古宙的下地壳基底中可能有较多年轻的玄武质岩石底侵加入。相比而言，铜陵区的Isr较高（0．707－0．709）、εNd(t)较低（－11－－16）、TDM高（1．7－2．2Ga)，接近扬子下地壳的特征。3，辽西－北京地区的Sr-Nd高位素组成以低的Isr(0.705-0.707)、变化的εNd(t)(-4--20)和TDM（0．7－2．1Ga)为特征，反映辽西－北京区下地壳组成比较复杂。其中北京－彰武地区的Sr-Nd同位素组成与汉诺坝玄武岩中的麻粒岩包体类似，远高于华北下地壳的εNd(t)值（－32－－44），推测埃达克质岩石并非来自古老的华北太古宙下地壳，而可能是中生代时增生在华北下地壳底部的年轻基性麻粒岩部分熔融形成的。此外，文中还讨论了用埃达克岩反演下地壳组成存在的不足。
-
-
[1] ［1］Atherton M P, Petford N. 1993. Generation of sodium-rich magmas from newly underplated basaltic crust. Nature, 362: 144-146
[2] ［2］Bai Z M, Xu S Z, Ge S W. 1991. The Badaling Granitoids. Beijing: GeologicalPublishing House, 1-169 (in Chinese)
[3] ［3］Chen J F, Foland K A, Zhou T X. 1985. Mesozoic granitoids of the Yangtze fold belt:Isotopic constraints on the magma sources.In: Wu L R et al. (eds.). The Crust - thesignificance of granite gneisses in the Lithosphere. Theophrastus, Athens,217-237
[4] ［4］Chen J F, Jahn B M. 1998. Crustal evolution of southeastern China:Nd and Srisotopic evidence. Tectonophys. , 284:101-133
[5] ［5］Chen J F, Zhou T X, Li X M et al. 1993. Sr and Nd isotopic constraints on sourceregions of the intermediate and acidic intrusions from southern Anhui province.Geochimica, 3: 261-268 (in Chinese with English abstract)
[6] ［6］Chen J F, Zhou T X, Zhang X et al. 1994. Isotopic geochemistry of Cu-mineralizedintrusions from the Middle and Lower Reaches of Yangtze River. In: Chen J F (ed.) IsotopicGeochemistry Studies. Hangzhou: Zhejiang Univ. Publ. , 214 - 229 (in Chinese with Englishabstract)
[7] ［7］Chen Y X, Chen W J et al. 1997. Mesozoic volcanic rocks in western LiaoningProvince and surrounding area - geochronology,geochemistry and tectonic environment.Beijing: Seismological Press. 1-279 (in Chinese with English abstract)
[8] ［8］Defant M J, Drummond M S. 1990. Derivation of some modern arc magmas by melting ofyoung subdction Lithosphere. Nature,662-665
[9] ［9］Deng W M, Zheng X L, Yukio Malsumoto. 1996. Petrological characteristics and agesof Cenozoic volcanic rocks from the Hoh Xil Mts., Qinghai Proince. Acta Petroligica etMineralogica,15: 289-298 (in Chinese with English abstract)
[10] ［10］Deng W M. 1998. Cenozoic intraplate volcanic rocks in the northern Qinghai -Xizang Plateau. Beijing: Geological Publishing House. (in Chinese with English abstract)
[11] ［11］Drummond M S, Defant M J. 1990. A model for trondhjemitetonalite-dacite genesisand crustal growth via slab melting:Archean to modern comparisons. J. Geophys. Res. , 95(B13):21503-21521
[12] ［12］Fan Q C, Sui J L, Liu R X and Zhou X M. 2001. Eclogite facies garnet-pyroxenitexenolith in Hannoba area: New evidence of magma underplating. Acta Petrologica Sinica,17(1): 1-6
[13] ［13］Farmer G L. 1992. Magmas as tracers of lower crustal composition:an isotopicapproach. In: Fountain D M (ed.). The Continent Lower Crust. Elsevier: Sci. Publ. ,363-390
[14] ［14］Feeley T C, Davidson J P. 1995. Petrology of calc-alkaline lavas at VolcanoOllague and the origin of compositional diversity at Central Andean Stratovolcanoes. J.Petrol., 35: 1295-1340
[15] ［15］Gao S, Luo T C, Zhang B R, Zhang H F, Han Y W, Zhao Z D.1999. Structure andcomposition of the continental crust in east China. Science in China (series D),42:129-140
[16] ［16］Hong D W, Xie X L, Zhang J S. 1999. An exploration on the composition, nature andevolution of mid-lower crust in south China based on the Sm-Nd isotopic data of granites.Geol. J.China Univ. , 5:361-371 (in Chinese with English abstract)
[17] ［17］Jahn B-M, Wu F Y, Lo C-H et al. 1999. Crust-mantle interaction induced by deepsubduction of the continental crust:geochemical and Sr-Nd isotopic evidence frompost-collisional mafic-ultramafic intrutions of the northern Dabie complex,central China.Chem. Geol. , 157:119-146
[18] ［18］Kay S M, Ramos V A, Marques M. 1993. Evidence in Cerro Pampa Volcanic Rocks forSlab-Melting Prior to Ridge-Trench Collision in Southern South American. J. Geol. , 101:703-714
[19] ［19］Lai S C, Liu C Y. 2001. Enriched upper mantle and eclogitic lower crust in northQiangtang, Qinghai-Tibet Plateau: petrological and geochemical evidence from the Cenozoicvolcanic rocks.Acta Petrologica Sinica, 17(3): 459-468
[20] ［20］Li G M. 2000. Petrologic features and genesis of Cenozoic volcanic rocks,Qiangtang area, northern Tibetan Plateau. GeologyGeochemistry, 28 (2): 38 43 (in Chinesewith English abstract)
[21] ［21］Liu J Q. 1999. Volcanoes in China. Beijing: Science Press. (in Chinese)
[22] ［22］Liu Y S, Gao S. 1998. Anatexis of the continental crust and granites as tracers oflower crustal composition. Geological Sciences and Technology Information, 17 (3): 31- 38(in Chinese with English abstract)
[23] ［23］Ma C Q, Ehlers C, Xu C H et al. 2000. The roots of the Dabieshanultrahigh-pressure metamoophic terrane: constraints from geochemistry and Nd-Sr isotopesystematics. Precamb. Res. ,102:279-301
[24] ［24］Ma C Q, Yang K G, Tang Z H. 1994. Magma-dynamics of granitoids-theory, method anda case study of the eastern Hubei granotoids. Wuhan: Chinese University of GeosciencesPress (in Chinese with English abstract)
[25] ［25］Ma C Q, Yang K G, Xu C H. 1999. Mesozoic potassic magmatism in the DabieMountains: implication for exhumation of ultrahigh-pressure metamorphic terranes. ActaPetrologica Sinica, 15:379-395 (in Chinese with English abstract)
[26] ［26］Mao J R, Su Y X, Chen S Y. 1990. Felsic intrusions and mineralization in themiddle and lower paer of Yangtze River.Beijing: Geological Publishing House, 1-191 (inChinese with English abstract)
[27] ［27］Martin H. 1999. Adakitic magmas: modern analogues of Archean granitoids. Lithos,46:411-429
[28] ［28］Martin H. 1986. Effect of steeper Archean geochermal gradient on geochemistry ofsubduction-zone magmas. Geology, 14: 753-756
[29] ［29］Peacock S M, Rushmer T, Thompson A B. 1994. Partial melting of subducting oceaniccrust. Earth Planet. Sci. Lett. , 121: 227-244
[30] ［30］Rapp R P, Watson E B, Miller C F. 1991. Partial melting of amphibolite/eclogiteand the origin of Archaean trondhjemites and tonalites. Precamb. Res. , 51:1-25
[31] ［31］Roberts M P, Clemens J D. 1993. Origin of high-potassium, calcalkaline, I-typegranitoids. Geology, 21:825-828
[32] ［32］Rudnick R L, Fountain D M. 1995. Nature and composition of the continental crust:a lower crust perspective. Res. Geophys. ,33:267-309
[33] ［33］Tan F W, Pan G T, Xu Q. 2000. The uplift of Qinghai-Xizang Plateau and geochemicalcharacteristics of Cenozoic volcanic rocks from the center of Qiangtang, Xizang. ActaPetrologica et Mineralogica, 19:121-130 (in Chinese with English abstract)
[34] ［34］Taylor S R, Mclennan S M. 1985. The Continental Crust: Its Composition andEvolution. Blackwell Sci. Publ. Turner S,Arnaud N, Liu J et al. 1993. Post- collision,shoshonitic volcanism on the Tibetan Plateau: implications for convective thinning of theLithosphere and the source of ocean island basalts. J. Petrol. , 37:45-71
[35] ［35］Wang Q, Zhao Z H, Xiong X Let al. 2001. Crustal growth and the melting of maficlower crust: evidence from the Shaxi adakitic sodic quartz diorite-porphyrites, in Anhuiprovince, China.Geochimica, 30 (4): 353- 362 (in Chinese with English abstract)
[36] ［36］Wang Y and Zhang Q. 2001. A granitoid complex from Badaling area, Beijing, NorthChina: composition, geochemical characteristics and its implications. Acta PetrologicaSinica, 17(4)533-540
[37] ［37］Xie Z, Chen J F, Zhou T X et al. 1996. Nd isotopic compositions of metamorphic andgranitic rocks gromn Dabie Orogen and their geological significance. Acta PetrologicaSinica, 12: 401-408(in Chinese with English abstract)
[38] ［38］Xing F M. 1996. Petrological and Nd, Sr, Pb isotopic evidence for genesis ofMesozoic magmatic rocks in Nanjing-Wuhu area.Acta Petrologica et Mineralogica, 15: 126-137
[39] ［39］Xu P F, Sun R M, Liu F T et al. 2000. Seismic tomography showing subduction andslab breakoff of the Yangtze block beneath the Dabie-Sulu orogenic belt. Chinese ScienceBulletin,45:70-73
[40] ［40］Xu P F. 2001. 3-D velocity image of the lithosphere of Dabie-Sulu orogenic beltand the eastern North China Block. Post-doctor research paper of IGGCAS ( Institute ofGeology and Geophysics, Chinese Academy of Sciences)
[41] ［41］Yang J H. 1999. Age and metallogenic dynamics of gold mineralization in JiaodongPeninsula, eastern China:Constraints on the interaction of mantle/crust andmetallogenesis/lithospheric evolution. Ph. D. Dissert. Institute of Geology andGeophysics, CAS, Beijing, China. 1-133. (in Chinese with English abstract)
[42] ［42］Yogodzinski G M, Lees J M, Churikova T G et al. 2001. Geochemical evidence for themelting of subducting oceanic lithosphere at plate edges. Nature, 409(25): 500-504
[43] ［43］Yu J H, Fu H Q, Zhang F L et al. 1994. The plutonism of Beijing area. Beijing:Geological Publishing House (in Chinese)
[44] ［44］Zhai M G, Liu W J. 2001. The formation of granulite and its contribution toevolution of the continental crust. Acta Petrologica Sininca, 17 (1): 28- 38
[45] ［45］Zhang G H, Zhou X H, Sun M et al. 1998. Sr, Nd and Pb isotopic characteristics ofgranulite and pyroxenite xenoliths in Hannoba basalts, Hebei Province, and theirimplications for geologic processes. Acta Petrologica Sinica. 14: 190- 197 (in Chinese)
[46] ［46］Zhang H F, Zhao Z D, Luo T C et al. 1995. Crustal growth and lower crust nature ofNorth Qinling: study of Sm-Nd isotopic model ages. Acta Petrologica Sinica, 11:160-170 (inChinese with English abstract)
[47] ［47］Zhang Q, Wang Y, Qian Q et al. 2001a. The characteristics andtectonic-metallogenic significances of the Mesozoic adakites in eastern China. ActaPetrologica Sinica, 17: 236- 244 (in Chinese with English abstract)
[48] ［48］Zhang Q, Qian Q, Erchie Wang. 2001b. Existence of East China Plateau in mid-lateYanshan period: implication from adakites.Scientia Geologica Sinica, 36: 248- 255 (inChinese with English abstract)
[49] ［49］白志民,许淑贞,葛世伟.1991.八达岭花岗杂岩.北京:地质出版社,1-172
[50] ［50］陈江峰,周泰禧,李学明等.1993.安徽南部燕山期中酸性侵入岩的源区锶、钕同位素制约.地球化学(3):261-274
[51] ［51］陈江峰,周泰禧,张巽等.1994.长江中下游岩带含铜岩体的同位素地球化学研究.见:同位素地球化学研究(陈江峰主编).杭州:浙江大学出版社,214-229
[52] ［52］陈义贤,陈文寄.1997.辽西及邻区中生代火山岩-年代学、地球化学和构造背景.北京:地震出版社
[53] ［53］邓万明,郑锡澜,松本征夫.1996.青海可可西里地区新生代火山岩的岩石特征与时代.岩石矿物学杂志,15:289-298
[54] ［54］邓万明.1998.青藏高原北部新生代板内火山岩.北京:地质出版社7.樊棋诚,刘若新,李惠民等.1998.汉诺坝捕虏体麻粒岩锆石年代学与稀土元素地球化学.科学通报,43:133-137
[55] ［55］樊棋诚,隋建立,刘若新,周新民.2001.含诺坝榴辉岩相石榴辉石岩:岩浆底侵作用新证据.岩石学报,17:1-6
[56] ［56］高山,骆庭川,张本仁等.1999.中国东部地壳的结构和组成.中国科学(D),29:204-213
[57] ［57］洪大卫,谢锡林,张季生.1999.从花岗岩的Sm-Nd同位素探讨华南中下地壳的组成/性质和演化.高校地质学报,5:361-371
[58] ［58］绍聪,刘池阳.2001.青藏高原北羌塘榴辉岩质下地壳及富集型地幔源区.岩石学报,17:459-468
[59] ［59］李光明.2000.藏北羌塘地区新生代火山岩岩石特征及其成因探讨.地质地球化学,28:38-43
[60] ［60］刘嘉麒.1999.中国火山.北京:科学出版社
-
计量
- 文章访问数: 21237
- PDF下载数: 8552
- 施引文献: 0
下载: