Crust-Mantle Transitional Zone beneath SW Tianshan Area Constrained by the Seismic and Calculated Velocities of the Deep-Seated Xenoliths in Tuoyun Basaltic Rocks
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摘要: 对我国西部新疆托云地区中新生代火山岩中的深源岩石包体进行了波速计算, 并与地球物理深部探测技术相结合, 共同限定了西南天山深部壳-幔过渡带的组成和性质.托云地区麻粒岩、橄榄岩的计算波速分别是6.98~7.36 km/s、7.96~8.47 km/s.这些结果与地震反射探测地震波速的对比, 说明在西南天山岩石圈剖面中的40~48km处存在较明显的壳-幔过渡带.过渡带自上而下主要由石英麻粒岩、辉石麻粒岩和橄榄石/石榴石麻粒岩组成, 然后进入尖晶石相二辉橄榄岩组成的上地幔.这样的岩石圈壳-幔结构可以用岩浆底侵-变质作用来解释.Abstract: The velocities of a series of deep-seated xenoliths in Late Mesozoic-Cenozoic basaltic rocks from Tuoyun basin, western Xinjiang (NW China), are calculated.These data, combined with the published seismic velocities for the area, are used to define the composition and structure of the crust-mantle transitional zone beneath southwestern Tianshan.The calculated velocities of peridotite and granulite xenoliths are 6.98-7.36 km/s and 7.96-8.47 km/s, respectively.The comparison of these data with the seismic velocities shows the presence of the crust-mantle transitional zone in 40-48 km beneath southwestern Tianshan.The zone consists of quartz granulite, pyroxene granulite and olivine/garnet granulite from top to bottom, and then transfers into the upper mantle mainly composed of spinel-facies lherzolite with or without volatile component minerals (phlogopite or amphibole).Such crust-mantle structure of lithosphere can be well explained by magma underplating and metamorphism.
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Key words:
- southwestern Tianshan /
- xenolith /
- velocity /
- crust-mantle transitional zone /
- magma underplating
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图 1 研究样品的位置(据Brookfield, 2000略修改)
Fig. 1. The locality map of the studied samples
表 1 麻粒岩、橄榄岩包体的矿物组成与含量(%)
Table 1. The mineral composition and mode of granulite and peridotite xenoliths
表 2 麻粒岩、橄榄岩包体的计算波速
Table 2. The calculated velocities of granulite and peridotite xenoliths
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[1] Avé Lallemant, H. G., Mercier, J. C. C., Cater, N. L., et al., 1980. Rheology of the upper mantle: Inferences from peridotite xenoliths. Tectonophysics, 70: 85-113. doi: 10.1016/0040-1951(80)90022-0 [2] Brookfield, M. E., 2000. Geological development and Phanerozoic crustal accretion in the western segment of the southern Tienshan. Tectonophysics, 328: 1-14. doi: 10.1016/S0040-1951(00)00175-X [3] Chen, Z. F., Cheng, S. D., 1997. Opening and closing tectonics and mineralization in Xinjiang. Science and Technology and Health Publishing House, 乌鲁木齐(in Chinese). [4] Christensen, N. I., 1989. Seismic velocity. In: Camichael, R. S., ed., Practical handbook of physical properties ofrocks and minerals. CRC Press, Boca Raton, 429-534. [5] Deng, J. F., Su, S. G., Liu, C., et al., 2006. Discussion on the lithospheric thinning of the North China craton: Delamination or thermal erosion and chemical metasomatism. Earth Science Frontiers, 13 (2): 105-119 (in Chinese with English abstract). [6] Fan, Q. C., Liu, R. X., 1996. The high temperature granulite xenoliths in the Hannuoba basalt. Chinese Science Bulletin, 41 (3): 235-238 (in Chinese). doi: 10.1360/csb1996-41-3-235 [7] Fan, Q. C., Sui, J. L., 2001. The granulite-eclogite facies cumulate xenoliths in Hannuoba area—The evidence of the crust-mantle transitional zone. Bulletin of National Science Foundation of China, 1: 23-27 (in Chinese with English abstract). [8] Fan, Q. C., Zhang, H. F., Sui, J. L., et al., 2005. Magma underplating and composition of crust-mantle margin nowadays: Evidence from the petrology and geochemistry of the xenoliths in Hannuoba area. Science in China (Series D), 35 (1): 1-14 (in Chinese). [9] Gao, S., Roberta, L. R., Richard, W. C., et al., 2003. Removal of lithospheric mantle in the North China craton: ReOs isotopic evidence for coupled crust-mantle growth. Earth Science Frontiers, 10 (3): 61-67 (in Chinese with English abstract). [10] Han, B. F., Wang, X. C., He, G. Q., et al., 1998. Discovery of upper mantle and lower crust xenolithin Early Cretaceous volcanic rock from southwest Tianshan. Chinese Science Bulletin, 43 (23): 2544-2547 (in Chinese). doi: 10.1360/csb1998-43-23-2544 [11] Han, B. F., Wang, X. C., He, G. Q., et al., 1999. Discovery of mantle and lower crust xenoliths from Early Cretaceous volcanic rocks of southwestern Tianshan, Xinjiang. Chinese Science Bulletin, 44 (12): 1119-1123. doi: 10.1007/BF02886139 [12] Liu, G., 2004. Metallogenic perspective analyzing of representative deposits in southwest Tianshan. In: He, G. Q., Xu, X., eds., Geology and mineral collection of Tianshan, Xinjiang, China. Geological Publishing House, Beijing, 119-124 (in Chinese). [13] Liu, Y. S., Gao, S., Zhou, L., et al., 2001. Geochronology and geodynamic implications of the felsic granulite xenoliths from the Hannuoba basalt. Geochimica, 30 (1): 51-56 (in Chinese with English abstract). [14] Luo, Z. H., Bai, Z. D., Zhao, Z. D., et al., 2003. Cenozoic magmatism in the south and north rims of Tarimbasin: Petrogenesis and tectonic implications. Earth Science Frontiers, 10 (3): 179-189 (in Chinese with English abstract). [15] Luo, Z. H., Zhang, W. H., Deng, J. F., et al., 2000. Characteristic and geological significance of the deep-seated xenoliths in Cenozoic basalt in Kangxiwa, western Kunlun Mountains, China. Earth Science Frontiers, 7 (1): 295-298 (in Chinese with English abstract). [16] Mooney, W. D., Meissner, R., 1992. Multi-genetic origin of crustal reflectivity: A review of seismic reflection profiling of the continental lower crust and MOHO. In: Fountain, D. M., et al., eds., Continental lower crust. Elsevier, Amsterdam-London-New York-Tokyo; 45-71. [17] Rudnick, R. L., 1995. Continental crust: Growth from below. Nature, 347: 711-712. [18] Stosch, H. G., Schmuker, A., Reys, C., 1992. The nature and geological history of the deep crust under the Eifel. Germany Terra Nova, 4 (1): 53-62. doi: 10.1111/j.1365-3121.1992.tb00450.x [19] Wang, Y. B., Wang, Y., Liu, X., et al., 2000. Geochemical characteristics and genesis of Late Cretaceous to Paleocene basalts in Tuoyun basin, South Tianshan Mountain. Acta Petrologica Mineralogica, 19 (2): 131-139 (in Chinese with English abstract). [20] Wang, Y. C., Huang, B. C., Zhu, R. X., et al., 2004. The paleomagnetic results of Cenozoic volcanic rocks in Tuoyun basin, Southwest Tianshan and its tectonic implications. Chinese Science Bulletin, 49 (10): 993-999 (in Chinese). doi: 10.1360/csb2004-49-10-993 [21] Xiao, X. C., Tang, Y. Q., Feng, Y. M., et al., 1992. Tectonics of North Xinjiang and its adjacent region. Geological Publishing House, Beijing, 2-3 (in Chinese). [22] Xu, W. L., Wang, Q. H., Wang, D. Y., et al., 2004. Processes and mechanism of Mesozoic lithospheric thinning ineastern North China craton: Evidence from Mesozoic igneous rocks and deep-seated xenoliths. Earth Science Frontiers, 11 (3): 309-317 (in Chinese with English abstract). [23] Xu, X. Y., Xia, L. Q., Xia, Z. C., et al., 2003. Geochemistry and genesis of Cretaceous-Paleogene basalts from the Tuoyun basin, Southwest Tianshan Mountains. Geochimica, 32 (6): 551-560 (in Chinese with English abstract). [24] Zhai, M. G., Fan, Q. C., 2002. Mesozoic replacement of bottom crust in North China craton: An orogenic mantlecrust interaction. Acta Petrologica Sinica, 18 (1): 1-8 (in Chinese with English abstract). [25] Zhang, Z. C., Xiao, X. C., Wang, J., et al., 2002. Discovery of enclaves from Cenozoic Pulu volcanic rocks of west Kunlun Mountains and their geological implications. Earth Science—Journal of China University of Geosciences, 27 (4): 386-390 (in Chinese with English abstract). [26] Zhao, J. M., 2005. Lithospheric structure and geodynamics of Tianshan orogenic belt. Seismological Publishing House, Beijing, 3-105 (in Chinese). [27] Zhao, J. M., Liu, G. D., Lu, Z. X., et al., 2003. Lithospheric structure and dynamic processes of the Tianshan orogenic belt and the Junggar basin. Tectonophysics, 376: 199-239. doi: 10.1016/j.tecto.2003.07.001 [28] Zheng, J. P., Griffin, W. L., O'Reilly, S. Y., et al., 2006a. Granulite xenoliths and their zircons, Tuoyun, NW China: Insights into southwestern Tianshan lower crust. Precambrian Research, 145: 159-181. doi: 10.1016/j.precamres.2005.12.001 [29] Zheng, J. P., Grffin, W. L., O'Reilly, S. Y., et al., 2006b. The lithospheric mantle beneath the southwestern Tianshan area, Northwest China. Contributions to Mineralogy Petrology, 151 (4): 457-479. doi: 10.1007/s00410-006-0071-x [30] Zheng, J. P., Lu, F. X., O'Reilly, S. Y., et al., 2001. Traceelement of Tuoyun clinopyroxene: Implication for the deep processes of lithospheric mantle beneath the southwest Tianshan, West China. Chinese Science Bulletin, 46 (6): 497-502 (in Chinese). doi: 10.1360/csb2001-46-6-497 [31] Zheng, J. P., Lu, F. X., Yu, C. M., et al., 2006. Peridotitic petrochemistry of the eastern North China: Significancefor lithospheric mantle evolution. Earth Science—Journal of China University of Geosciences, 31 (1): 49-56 (in Chinese with English abstract). [32] Zheng, J. P., Luo, Z. H., Yu, C. M., et al., 2005. Geochemistry and zircon U-Pb ages of granulite xenulith from Tuoyun basalts, Xinjiang: Implications for the petrogenesis and the lower crustal nature beneath southwestern Tianshan. Chinese Science Bulletin, 50 (8): 793-801 (in Chinese). [33] Zhou, Q. J., Zheng, J. J., 1990. Tectonic analysis of Tarim. Science Press, Beijing, 27-59 (in Chinese). [34] Zhou, X. M., Yu, J. H., Xu, X. S., et al., 1992. Discovery and implications of the granulite xenoliths in basalt from Nüshan. Chinese Science Bulletin, 37 (13): 1198-1201 (in Chinese). doi: 10.1360/csb1992-37-13-1198 [35] 陈哲夫, 成守德, 1997. 新疆开合构造与成矿. 乌鲁木齐: 新疆科技卫星出版社. [36] 邓晋福, 苏尚国, 刘翠, 等, 2006. 关于华北克拉通燕山期岩石圈减薄的机制与过程的讨论: 是拆沉, 还是热侵蚀和化学交代. 地学前缘, 13 (2): 105-119. doi: 10.3321/j.issn:1005-2321.2006.02.009 [37] 樊祺诚, 刘若新, 1996. 汉诺坝玄武岩中高温麻粒岩捕虏体科学通报, 41 (3): 235-238. [38] 樊祺诚, 隋建立, 2001. 汉诺坝麻粒岩相-榴辉岩相堆晶岩捕虏体——壳-幔过渡带的证据. 中国科学基金, 1: 23-27. doi: 10.3969/j.issn.1000-8217.2001.01.007 [39] 樊祺诚, 张宏福, 隋建立, 等, 2005. 岩浆底侵作用与汉诺坝现今壳-幔边界组成——捕虏体岩石学与地球化学证据. 中国科学(D辑), 35 (1): 1-14. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK200501000.htm [40] 高山, Roberta, L. R., Richard, W. C., 等, 2003. 华北克拉通岩石圈地幔置换作用和壳幔生长耦合的Re-Os同位素证据. 地学前缘, 10 (3): 61-67. doi: 10.3321/j.issn:1005-2321.2003.03.005 [41] 韩宝福, 王学潮, 何国琦, 等, 1998. 西南天山早白垩世火山岩中发现地幔和下地壳捕虏体. 科学通报, 43 (23): 2544-2547. doi: 10.3321/j.issn:0023-074X.1998.23.019 [42] 刘刚, 2004. 利用遥感技术对西南天山几个典型矿床的成矿远景分析. 见: 何国琦, 徐新, 中国新疆天山地质与矿产论文集. 北京: 地质出版社, 119-124. [43] 刘勇胜, 高山, 周炼, 等, 2001. 汉诺坝长英质麻粒岩包体同位素年代学及其地球动力学意义. 地球化学, 30 (1): 51-56. doi: 10.3321/j.issn:0379-1726.2001.01.006 [44] 罗照华, 白志达, 赵志丹, 等, 2003. 塔里木盆地南北缘新生代火山岩成因及其地质意义. 地学前缘, 10 (3): 179-189. doi: 10.3321/j.issn:1005-2321.2003.03.017 [45] 罗照华, 张文会, 邓晋福, 等, 2000. 西昆仑地区新生代火山岩中的深源包体. 地学前缘, 7 (1): 295-298. doi: 10.3321/j.issn:1005-2321.2000.01.028 [46] 王彦斌, 王永, 刘训, 等, 2000. 南天山托云盆地晚白垩世-早第三纪玄武岩的地球化学特征及成因探讨. 矿物岩石学杂志, 19 (2): 131-139. https://www.cnki.com.cn/Article/CJFDTOTAL-YSKW200002004.htm [47] 王永成, 黄宝春, 朱日祥, 等, 2004. 西南天山托云盆地新生代火山岩古地磁结果及构造意义. 科学通报, 49 (10): 993-999. doi: 10.3321/j.issn:0023-074X.2004.10.014 [48] 肖序常, 汤耀庆, 冯益民, 等, 1992. 新疆北部及邻区大地构造. 北京: 地质出版社, 2-3. [49] 许文良, 王清海, 王冬艳, 等, 2004. 华北克拉通东部中生代岩石圈减薄的过程与机制: 中生代火成岩和深源捕虏体证据. 地学前缘, 11 (3): 309-317. doi: 10.3321/j.issn:1005-2321.2004.03.029 [50] 徐学义, 夏林圻, 夏祖春, 等, 2003. 西南天山托云地区白垩纪-早第三纪玄武岩地球化学及其成因机制. 地球化学, 32 (6): 551-560. doi: 10.3321/j.issn:0379-1726.2003.06.005 [51] 翟明国, 樊祺诚, 2002. 华北克拉通中生代下地壳置换: 非造山过程的壳幔交换. 岩石学报, 18 (1): 1-8. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB200201000.htm [52] 张招崇, 肖序常, 王军, 等, 2002. 西昆仑山普鲁新生代火山岩中包体的发现及其地质意义. 地球科学——中国地质大学学报, 27 (4): 386-390. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200204006.htm [53] 赵俊猛, 2005. 天山造山带结构与动力学. 北京: 地震出版社, 3-105. [54] 郑建平, 路凤香, O'Reilly, S. Y., 等, 2001. 新疆托云地幔单斜辉石微量元素与西南天山岩石圈深部过程. 科学通报, 46 (6): 497-502. doi: 10.3321/j.issn:0023-074X.2001.06.013 [55] 郑建平, 路凤香, 余淳梅, 等, 2006. 华北东部橄榄岩岩石化学特征及其岩石圈地幔演化意义. 地球科学——中国地质大学学报, 31 (1): 49-56. https://www.cnki.com.cn/Article/CJFDTOTAL-DQKX200601007.htm [56] 郑建平, 罗照华, 余淳梅, 等, 2005. 新疆托云麻粒岩捕虏体地球化学和锆石年代学: 岩石成因及西南天山下地壳性质. 科学通报, 50 (8): 793-801. doi: 10.3321/j.issn:0023-074X.2005.08.013 [57] 周清杰, 郑建京, 1990. 塔里木构造分析. 北京: 科学出版社, 27-59. [58] 周新民, 于津海, 徐夕生, 等, 1992. 女山玄武岩中麻粒岩捕虏体的发现与意义. 科学通报, 37 (13): 1198-1201. https://www.cnki.com.cn/Article/CJFDTOTAL-KXTB199213013.htm