西藏冈底斯南带辉长岩及其所反映的壳幔作用信息
Gabbros from southern Gangdese: implication for mass exchange between mantle and crust
-
摘要: 在巨型冈底斯岩浆岩带南端产出有一个辉长岩带,与雅鲁藏布江蛇绿岩带平行共生.辉长岩带中以辉长岩为主,与冈底斯花岗质岩石空间上呈渐变过渡接触关系,表现为接触带附近岩石成分的规律变化,并出现暗色微粒包体.本文在项目组多年来对冈底斯岩浆岩带研究的基础上,对拉萨曲水县城-日喀则一带的辉长岩类进行了详细的野外观测,选择了典型露头系统采集了样品,系统的岩石学、地球化学及同位素地球化学分析和研究表明该辉长岩类的SiO2 49%～55%、Mg#49～66,近于原始基性岩浆,REE曲线平缓右倾,无明显负Eu异常,表明未发生明显的岩浆分异作用,其87Sr/86Sr比值变化在0.7036-07051、143Nd/144Nd为0.5128～0.5131,且εNd为2.34～6.87,其206Pb/204Pb,207Pb/204Pb,208Pb/204Pb分别为17.9095,15.4986和38.0176.这些特征都表明该辉长岩属于PREMA源区物质局部熔融而成,并在上侵就位过程中受到壳源物质影响.已有SHRIMP锆石U-Pb年龄表明该辉长岩类形成于40～53Ma,与曲水岩体岩浆混合时代一致.因此可以推断印度-欧亚陆陆碰撞过程中,随着俯冲板片的折返断离,具有亏损特征的普通幔源物质在始新世局部熔融,其熔浆底侵、上升,不同程度地与壳源花岗质岩浆混合,形成冈底斯辉长岩带,其成因与大陆碰撞密切相关.
-
-
[1] Anderson AT. 1976. Magma mixing: Petrlogical process and volcanological tool. J. Volcanol. Geotherm. Res. , 1 : 3 -33
[2] Bonin B. 2004. Docoeval mafic and felsic magmas in post-collisional to within-plate regions necessarily imply two contrasting, mantle and crustal, sources? A review. Lithos, 78:1 -24
[3] Deng JF, Lou ZH, Su SG et al. 2004. Petrological origin, tectonic environment and metallogeny. Beijing: Geological Publish House, 244 - 276
[4] Dider J. 1991. Granite and Their Enclaves. Elsevier, Amsterdam
[5] Dong GC, Mo XX, Zhao ZD et al. 2004. Magma mixing from mantle and crust source in Gangdise: Evidences from isotopic dating. Seminar of National Petrology and Geodynamics in 2004, 38 - 39
[6] Dong GC, Mo XX, Zhao ZD et al. 2006. Magma mixing of mantle and crust source during India-Eurasian continental collision: Evidences from Gangdise magma belt. Acta Petrologica Sinica, 22 ( 3 ) : 835 - 844
[7] Dong G, Mo X, Zhao Z et al. 2005. Geochronologic constraints by SHRIMP Ⅱ zircon U-Pb dating on magma underplating in the Gangdise Belt following India-Eurasia collision. Acta Geologica Sinica,79 (6) :787 - 794
[8] Du XT, Cheng ZL and Wang JW. 1982. A study on Rb-Sr isotopes in the intermediate-acid rock bodies of the Gangdise rock belt, Lhasa, Xizang. Geochemica, ( 3 ) : 217 - 225
[9] Du YS, Li ST and Cao Y. 2007. UAFC2 Related Origin of the Late Jurassic to Early Cretaceous Intrusions in the Tongguanshan Ore Field, Tongling, Anhui Province, East China. Geoscience, 12 (11):71-77
[10] Du YS and Li XJ. 2004. Discovery of Gabbroic Xenoliths from Early Cretaceous Intrusions in Tong, ling, Anhui Province , China and Its Geological Significance. Geological Journal of China Universities, 10 (3) :332 -342
[11] Du YS, Qin XL and Li XJ. 2004. Mesozoic mantle-derived magma underplating in Tong, ling , Anhui Province: Evidence from megacrysts and xenoliths. Acta of Petrologica et Mineralogica, 23 (2) :109 - 116
[12] Flower M, Russo RM and Tamaki K. 2001. Mantle contamination and the Izu-Bonin- Mariana (IBM) high-tide mark\\': Evidence for mantle extrusion caused by Tethyan closure. Tectonophysics, 333 : 9 - 34
[13] Huppert EH and Sparks RJS. 1988. The generation of granitic magmas by intrusion of basalt into continental crust. J. Petrol., 29(3) :599 -624
[14] Jiang W, Mo XX and Zhang SQ. 1996. Petrological studies on the Gangdese granites and mafic microgranular enclaves in Tibetan Plateau. Tethyan Geology, 22 : 90 - 96
[15] Jiang W, Mo XX, Zhao CH, Guo TY and Zhang SQ. 1999. Geochemical characteristics of granitoids and mafic microgranular enclaves in middle Gangdese of Tibetan Plateau. Acta Petrologica Sinica, 15 (1) : 89 -97
[16] Jill CW and Zhou YS. 1978. Magmatic belt in the Himalaya and Gangdese arc range and its genetic model. Geological Sciences, 4: 297 -312
[17] Jin CW and Xu RH. 1982. Granitoids in Himalayas and middle Gangdese. Petrological Research, 1:81 -95
[18] Jin CW. 1986. Enclaves in Qushui granite batholith, Lhasa, Tibet. Acta Petrologica Sinica, 2 (2): 23 -32
[19] Jin ZM and Gao S. 1996. Underplating and its significance for geodynamics in the evolution of the crust-mantle. Information of Science and Technology in Geology, 15(2) : 1 -7
[20] Liu CD, Mo XX, Luo ZH, Yu XH et al. 2004. Mixing events between the crust- and mantle-derived magmas in Eastern Kunlun: Evidence from zircon SHRIMP Ⅱ chronology. Chinese Science Bulletin, 49 : 823 -834
[21] Luo ZH, Xin HT, Chen BH et al. 2007. On the crust-mantle transition layer and its implications in continental geodynamics. Geosciences, 12(12) :421 -425
[22] Mo XX, Dong GC, Zhao ZD et al. 2005. Timing of magma mixing in Gangdese magmatic belt during the India-Asia collision: Zircon SHIRMP U-Pb dating. Acta Geologica sinica,79( 1 ) :66 -76
[23] Mo XX, Zhao ZD, Deng JF et al. 2003. Response of volcanism to the India-Asian collision. Earth Science Frontiers, 10 ( 3 ) : 135 - 148
[24] Mo XX, Zhao ZD et al. 2007. Mantle contributions to crustal thickening during continental collision : Evidence from Cenozoic igneous rocks in southern Tibet. Lithos,96:225 - 242
[25] Sharpe MR. 1985. Strontium isotopic evidence for preserved density stratification in the main zone of the Bushveld Complex, South Africa. Nature, 316:119 - 126
[26] Tan FW and Liu CJ. 1992. Preliminary study of the enclaves in Gangdise batholith, Xizang. Mineralogy and Petrology, 12(2) : 21 -27
[27] Tu KC, Zhang YQ, Zhao ZH et al. 1981. Characteristics and evolution of granotoids of south Xizang ( Tibet ). Geochemica, ( 1 ) : 1 - 7
[28] Wang Q, Xu JF, Zhao ZH et al. 2003. Origin Yanshanian intrusions and its constraint to the geodynamic process in Tongling, Anhui province. Science in China (series D), 33(4) : 323 -334
[29] Wang XZ, Tao Y and Ma YS. 2006. The Crust-Mantle mixing and the generation of granitic magmas. Bulletin of Mineralogy, Petrology and Geochemistry, 25 ( 2 ) : 183 - 188
[30] Wilker GPL and Skelhorn RR. 1996. Some association of acid and basic igneous rocks. Earth-Sci. Rev. , 2 : 93 - 109
[31] Xiong SQ, Zhou FH, Yao ZX et al. 2001. Airborne survey report of midwestern Qingzang plateau. Beijing: Geological Publish. House, 57 - 110
[32] Yang XM et al. 2000. Petrological Geochemistry. Hefei: The Publish. House of China University of Sciences and Technology
[33] Yin A and Harrison TM. 2000. Geologic evolution of the HimalayanTibetan orogen. Annual Review of Earth and Planetary Sciences, 28:211 -280
[34] Zhou S, Mo XX, Dong GC et al. 2004. ^40Ar-^39Ar geochronology of Cenozoic Linzizong volcanic rocks from Linzhou Basin, Tibet, China, and their geological implications, Chinese Science Bulletin, 49(18) :1970 -1979
[35] Zhou XR. 1994. Hybridization in the genesis of granitoids, Earth Science Frointiers, 1 ( 1 -2) : 87 -97
[36] 邓万明 钟大赉.壳—幔过渡带及其在岩石圈构造演化中的地质意义[J].科学通报,:.
[37] 桂训唐 成忠礼 王俊文.西藏拉萨冈底斯岩带中酸性岩类的Rb-Sr同位素研究[J].地球化学,1982,(3):217-225.
[38] 金成伟 周云生.喜马拉雅和冈底斯弧形山系中的岩浆岩带及其成因模式[J].地质科学,1978(4):297-312.
[39] 徐夕生 范钦成 S.Y.O＇Reilly 蒋少涌 W.L.Griffin 王汝成 邱检生.安徽铜官山石英闪长岩及其包体锆石U-Pb定年与成因探讨[J].科学通报,2004,18:1883-1891.
-
计量
- 文章访问数: 16389
- PDF下载数: 27462
- 施引文献: 0
下载: