西藏查孜地区中新世正长岩的锆石U-Pb年代学、地球化学及岩石成因

张士贞; 李勇; 李奋其; 秦雅东; 巩小栋

doi:10.3799/dqkx.2020.163

Volume 45 Issue 8

Aug. 2020

Turn off MathJax

Article Contents

Article Navigation > Earth Science > 2020 > 45(8): 2882-2893

Zhang Shizhen, Li Yong, Li Fenqi, Qin Yadong, Gong Xiaodong, 2020. Zircon U-Pb Geochronology, Geochemistry and Petrogenesis of Miocene Syenite in Chazi Area, Tibet. Earth Science, 45(8): 2882-2893. doi: 10.3799/dqkx.2020.163

Citation:

Zhang Shizhen, Li Yong, Li Fenqi, Qin Yadong, Gong Xiaodong, 2020. Zircon U-Pb Geochronology, Geochemistry and Petrogenesis of Miocene Syenite in Chazi Area, Tibet. Earth Science, 45(8): 2882-2893. doi: 10.3799/dqkx.2020.163

Citation:

PDF( 13983 KB)

Zircon U-Pb Geochronology, Geochemistry and Petrogenesis of Miocene Syenite in Chazi Area, Tibet

doi: 10.3799/dqkx.2020.163

Chengdu Center of China Geological Survey, Chengdu 610081, China

Received Date: 2020-03-13
Publish Date: 2020-08-15

Abstract

Abstract

The Chazi syenite mass is a newly discovered Miocene potassic-ultrapotassic intrusive rock in the middle Lhasa block, and its lithology is mainly composed of medium-coarse grained quartz hornblende syenite and porphyraceous quartz syenite. Mafic magmatic Enclaves were found in the syenite body. Petrography, zircon U-Pb dating and geochemical analysis were done, in order to study the petrogenesis of the Chazi syenite. Zircon U-Pb ages of 10.37±0.24 Ma and 11.06±0.39 Ma were obtained for these two rock types respectively, which represent that they were formed in the Miocene Epoch and product of post-collision magmatism in the Lhasa block. The Chazi syenite rocks have relatively high K₂O (6.75%-7.39%) and low MgO (1.44%-2.97%), with K₂O/Na₂O > 1, so they are potassic rocks. They have similar characteristics of trace elements to the ultrapotassic rocks:strongly enriched in large ion lithophile elements (LILE) such as Rb, Th, U and K, and light rare earth elements (LREE), relatively depleted in high field strength elements (HFSE) such as Nb, Ta, Zr, Hf, Ti and P, and heavy rare earth elements (HREE), but the contents of Cr (22.7×10^-6-64.6×10^-6) and Ni (18.9×10^-6-46.6×10^-6) of the syenite are obviously lower. Compared with porphyraceous quartz syenite rocks, the quartz hornblende syenite rocks have relatively higher SiO₂, and lower elements sucn as TiO₂, FeO^T, MgO, K₂O, Cr, Ni, REE and Y. By comprehensive analyses, it is proposed that the Chazi syenite was mainly formed by magma mixing, and produced by the mixing between the ultrapotassic magma that originated from the lithosphere mantle partial melting, and acid magma that originated from the continental crust partial melting. The chemical differcence of two rock types is mainly due to the different degrees of magma mixing and ratio of mixed magma.The Chazi syenite possibly resulted from convective thinning or delamination of over thickened mantle lithosphere.
- middle Lhasa Block,
- Chazi area,
- Miocene,
- syenite,
- zircon U-Pb age,
- geochemistry,
- magma mixing

FullText(HTML)

References(53)

References

Ahmed, H. A., Ma, C. Q., Wang, L. X., et al., 2018. Petrogenesis and Tectonic Implications of Peralkaline A-Type Granites and Syenites from the Suizhou-Zaoyang Region, Central China. Journal of Earth Science, 29(5):1181-1202. https://doi.org/10.1007/s12583-018-0877-2

Boynton, W. V., 1984. Cosmochemistry of the Rare Earth Elements: Meteorite Studies. In: Henderson, P., ed., Rare Earth Element Geochemistry. Elsevier, Amsterdam. https://doi.org/10.1016/b978-0-444-42148-7.50008-3

Chen, J.L., Xu, J.F., Kang, Z.Q., et al., 2007. Geochemistry and Origin of Miocene Volcanic Rocks in Cazé Area, South-Western Qinghai-Xizang Plateau. Geochimica, 36(5):437-447 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqhx200705002

Chen, J. L., Zhao, W. X., Xu, J. F., et al., 2012. Geochemistry of Miocene Trachytes in Bugasi, Lhasa Block, Tibetan Plateau:Mixing Products between Mantle- and Crust-Derived Melts? Gondwana Research, 21(1):112-122. https://doi.org/10.1016/j.gr.2011.06.008

Cheng, Z. H., Guo, Z. F, 2017. Post-Collisional Ultrapotassic Rocks and Mantle Xenoliths in the Sailipu Volcanic Field of Lhasa Terrane, South Tibet:Petrological and Geochemical Constraints on Mantle Source and Geodynamic Setting. Gondwana Research, 46:17-42. https://doi.org/10.1016/j.gr.2017.02.008

Ding, L., Kapp, P., Zhong, D. L., et al., 2003. Cenozoic Volcanism in Tibet:Evidence for a Transition from Oceanic to Continental Subduction. Journal of Petrology, 44(10):1833-1865. https://doi.org/10.1093/petrology/egg061

Ding, L., Yue, Y.H., Cai, F.L., et al., 2006. ⁴⁰Ar/³⁹Ar Geochronology, Geochemical and Sr-Nd-O Isotopic Characteristics of the High-Mg Ultrapotassic Rocks in Lhasa Block of Tibet:Implications in the Onset Time and Depth of NS-Striking Rift System. Acta Geologica Sinica, 80(9):1252-1261(in Chinese with English abstract). http://en.cnki.com.cn/article_en/cjfdtotal-dzxe200609003.htm

Dong, G.C., Mo, X.X., Zhao, Z.D., et al., 2006. Magma Mixing in Middle Part of Gangdise Magma Belt:Evidences from Granitoid Complex. Acta Petrologica Sinica, 22(4):835-844 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-YSXB200604007.htm

Gao, Y. F., Hou, Z. Q., Kamber, B. S., et al., 2007. Lamproitic Rocks from a Continental Collision Zone:Evidence for Recycling of Subducted Tethyan Oceanic Sediments in the Mantle beneath Southern Tibet. Journal of Petrology, 48(4):729-752. https://doi.org/10.1093/petrology/egl080

Gao, Y. F., Wei, R. H., Ma, P. X., et al., 2009. Post-Collisional Ultrapotassic Volcanism in the Tangra Yumco-Xuruco Graben, South Tibet:Constraints from Geochemistry and Sr-Nd-Pb Isotope. Lithos, 110(1-4):129-139. https://doi.org/10.1016/j.lithos.2008.12.005

Guo, Z. F., Wilson, M., Zhang, M. L., et al., 2013. Post-Collisional, K-Rich Mafic Magmatism in South Tibet:Constraints on Indian Slab-to-Wedge Transport Processes and Plateau Uplift. Contributions to Mineralogy and Petrology, 165(6):1311-1340. https://doi.org/10.1007/s00410-013-0860-y

Guo, Z. F., Wilson, M., Zhang, M. L., et al., 2015. Post-Collisional Ultrapotassic Mafic Magmatism in South Tibet:Products of Partial Melting of Pyroxenite in the Mantle Wedge Induced by Roll-Back and Delamination of the Subducted Indian Continental Lithosphere Slab. Journal of Petrology, 56(7):1365-1406. https://doi.org/10.1093/petrology/egv040

Huang, F., Chen, J. L., Xu, J. F., et al., 2015. Os-Nd-Sr Isotopes in Miocene Ultrapotassic Rocks of Southern Tibet:Partial Melting of a Pyroxenite-bearing Lithospheric Mantle? Geochimica et Cosmochimica Acta, 163:279-298. https://doi.org/10.1016/j.gca.2015.04.053

Li, Y., Zhang, S.Z., Li, F.Q., et al., 2018. Zircon U-Pb Ages and Implications of the Dianzhong Formation in Chazi Area, Middle Lhasa Block, Tibet. Earth Science, 43(8):2755-2766 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqkx201808016

Liu, D., Zhao, Z. D., DePaolo, D. J., et al., 2017. Potassic Volcanic Rocks and Adakitic Intrusions in Southern Tibet:Insights into Mantle-Crust Interaction and Mass Transfer from Indian Plate. Lithos, 268-271:48-64. https://doi.org/10.1016/j.lithos.2016.10.034

Liu, D., Zhao, Z.D., Zhu, D.C., et al., 2011. The Petrogenesis of Postcollisional Potassic-Ultrapotassic Rocks in Xungba Basin, Western Lhasa Terrane:Constraints from Zircon U-Pb Geochronology and Geochemistry. Acta Petrologica Sinica, 27(7):2045-2059 (in Chinese with English abstract). https://www.researchgate.net/publication/274713358_The_petrogenesis_of_postcollisional_potassic-ultrapotassic_rocks_in_Xungba_basin_western_Lhasa_terrane_Constraints_from_zircon_U-Pb_geochronology_and_geochemistry

Liu, D., Zhao, Z.D., Zhu, D.C., et al., 2014. Postcollisional Potassic and Ultrapotassic Rocks in Southern Tibet:Mantle and Crustal Origins in Response to India-Asia Collision and Convergence. Geochimica et Cosmochimica Acta, 143:207-231. https://doi.org/10.1016/j.gca.2014.03.031

Lu, R., Liang, T., Bai, F.J., et al., 2013. LA-ICP-MS U-Pb Zircon Age and Hf Isotope Composition of Mogou Syenite, Western Henan Province. Geological Review, 59(2):355-368 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzlp201302017

MacPherson, C. G., Dreher, S. T., Thirlwall, M. F., 2006. Adakites without Slab Melting:High Pressure Differentiation of Island Arc Magma, Mindanao, the Philippines. Earth and Planetary Science Letters, 243(3-4):581-593. https://doi.org/10.1016/j.epsl.2005.12.034

Montel, J. M., Vielzeuf, D., 1997. Partial Melting of Metagreywackes, Part Ⅱ. Compositions of Minerals and Melts. Contributions to Mineralogy and Petrology, 128(2-3):176-196. https://doi.org/10.1007/s004100050302

Niu, X. L., Yang, J. S., Liu, F., et al., 2016. Origin of Baotoudong Syenites in North China Craton:Petrological, Mineralogical and Geochemical Evidence. Science China Earth Sciences, 59(1):95-110. https://doi.org/10.1007/s11430-015-5216-1

Peccerillo, A., 1992. Potassic and Ultrapotassic Rocks:Compositional Characteristics, Petrogenesis, and Geologic Significance. Episodes, 15(4):243-251. https://doi.org/10.18814/epiiugs/1992/v15i4/002

Rapp, R. P., Watson, E. B, 1995. Dehydration Melting of Metabasalt at 8-32 kbar:Implications for Continental Growth and Crust-Mantle Recycling. Journal of Petrology, 36(4):891-931. https://doi.org/10.1093/petrology/36.4.891

Sun, C.G., Zhao, Z.D., Mo, X.X., et al., 2007. Geochemistry and Origin of the Miocene Sailipu Ultrapotassic Rocks in Western Lhasa Block, Tibetan Plateau. Acta Petrologica Sinica, 23(11):2715-2726 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98200711004

Sun, S. S., McDonough, W. F., 1989. Chemical and Isotopic Systematics of Oceanic Basalts:Implications for Mantle Composition and Processes. Geological Society, London, Special Publications, 42(1):313-345. https://doi.org/10.1144/gsl.sp.1989.042.01.19

Tian, S. H., Yang, Z. S., Hou, Z. Q., et al., 2017. Subduction of the Indian Lower Crust beneath Southern Tibet Revealed by the Post-Collisional Potassic and Ultrapotassic Rocks in SW Tibet. Gondwana Research, 41:29-50. https://doi.org/10.1016/j.gr.2015.09.005

Turner, S., Arnaud, N., Liu, J., et al., 1996. Post-Collision, Shoshonitic Volcanism on the Tibetan Plateau:Implications for Convective Thinning of the Lithosphere and the Source of Ocean Island Basalts. Journal of Petrology, 37(1):45-71. https://doi.org/10.1093/petrology/37.1.45

Wang, B.D., Xu, J.F., Zhang, X.G., et al., 2008. Petrogenesis of Miocene Volcanic Rocks in the Sailipu Area, Western Tibetan Plateau:Geochemical and Sr-Nd Isotopic Constraints. Acta Petrologica Sinica, 24(2):265-278 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSXB200802009.htm

Wang, Z.Z., Chen, X.H., Li, B., et al., 2019. The Discovery of the Paleoproterozoic Syenite in Helishan, Gansu Province, and Its Implications for the Tectonic Attribution of the Alxa Block. Geology in China, 46(5):1094-1104 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=zgdizhi201905011

Williams, H. M., Turner, S. P., Pearce, J. A., et al., 2004. Nature of the Source Regions for Post-Collisional, Potassic Magmatism in Southern and Northern Tibet from Geochemical Variations and Inverse Trace Element Modelling. Journal of Petrology, 45(3):555-607. https://doi.org/10.1093/petrology/egg094

Wu, Y. B., Zheng, Y. F., 2004. Genesis of Zircon and Its Constraints on Interpretation of U-Pb Age. Chinese Science Bulletin, 49(15):1554-1569. https://doi.org/10.1007/bf03184122

Zhang, L. H., Guo, Z. F., Zhang, M. L., et al., 2017. Post-Collisional Potassic Magmatism in the Eastern Lhasa Terrane, South Tibet:Products of Partial Melting of Mélanges in a Continental Subduction Channel. Gondwana Research, 41:9-28. https://doi.org/10.1016/j.gr.2015.11.007

Zhang, Z.Q., Wang, K.X., Wang, G., et al., 2018. Petrogenesis and Tectonic Significances of the Paleozoic Jiling Syenite in the Mountain Longshou Area, Gansu Province. Geological Review, 64(4):1017-1029 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzlp201804018

Zhao, D.H., Ping, X.Q., Zheng, J.P., et al., 2019. Geochemistry and Its Geological Significance of the Quartz Syenites in the Early Indosinian from the Tietang Gorge, West Qinling. Earth Science, 44(12):4203-4221 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqkx201912032

Zhao, W., Mechie, J., Brown, L. D., et al., 2001. Crustal Structure of Central Tibet as Derived from Project INDEPTH Wide-Angle Seismic Data. Geophysical Journal International, 145(2):486-498. https://doi.org/10.1046/j.0956-540x.2001.01402.x

Zhao, Z.D., Mo, X.X., Nomade, S., et al., 2006. Post-Collisional Ultrapotassic Rocks in Lhasa Block, Tibetan Plateau:Spatial and Temporal Distribution and Its Implications. Acta Petrologica Sinica, 22(4):787-794 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-YSXB200604003.htm

Zeng, Y.C., Chen, J.L., Xu, J.F., et al., 2017. Origin of Miocene Cu-bearing Porphyries in the Zhunuo Region of the Southern Lhasa Subterrane:Constraints from Geochronology and Geochemistry. Gondwana Research, 41:51-64. https://doi.org/10.1016/j.gr.2015.06.011

Zhu, D. C., Zhao, Z. D., Niu, Y. L., et al., 2011. The Lhasa Terrane:Record of a Microcontinent and Its Histories of Drift and Growth. Earth and Planetary Science Letters, 301(1-2):241-255. https://doi.org/10.1016/j.epsl.2010.11.005

Zhu, M.T., Wu, G., Xie, H.J., et al., 2011. Geochronology and Geochemistry of the Kekesai Intrusion in Western Tianshan, NW China and Its Geological Implications. Acta Petrologica Sinica, 27(10):3041-3054 (in Chinese with English abstract). http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98201110020

Zhu, R. Z., Lai, S. C., Qin, J. F., et al., 2018. Early-Cretaceous Syenites and Granites in the Northeastern Tengchong Block, SW China:Petrogenesis and Tectonic Implications. Acta Geologica Sinica (English Edition), 92(4):1349-1365. https://doi.org/10.1111/1755-6724.13631

陈建林, 许继峰, 康志强, 等, 2007.青藏高原西南部查孜地区中新世钾质火山岩地球化学及其成因.地球化学, 36(5):437-447. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dqhx200705002

丁林, 岳雅慧, 蔡福龙, 等, 2006.西藏拉萨地块高镁超钾质火山岩及对南北向裂谷形成时间和切割深度的制约.地质学报, 80(9):1252-1261. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dizhixb200609003

董国臣, 莫宣学, 赵志丹, 等, 2006.冈底斯岩浆带中段岩浆混合作用:来自花岗杂岩的证据.岩石学报, 22(4):835-844. http://d.wanfangdata.com.cn/Periodical_ysxb98200604007.aspx

李勇, 张士贞, 李奋其, 等, 2018.拉萨地块中段查孜地区典中组火山岩锆石U-Pb年龄及地质意义.地球科学, 43(8):2755-2766. doi: 10.3799/dqkx.2018.593

刘栋, 赵志丹, 朱弟成, 等, 2011.青藏高原拉萨地块西部雄巴盆地后碰撞钾质-超钾质火山岩年代学与地球化学.岩石学报, 27(7):2045-2059. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98201107013

卢仁, 梁涛, 白凤军, 等, 2013.豫西磨沟正长岩LA-ICP-MS锆石U-Pb年代学及Hf同位素.地质论评, 59(2):355-368. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzlp201302017

孙晨光, 赵志丹, 莫宣学, 等, 2007.青藏高原拉萨地块西部中新世赛利普超钾质岩石的地球化学与岩石成因.岩石学报, 23(11):2715-2726. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98200711004

王保弟, 许继峰, 张兴国, 等, 2008.青藏高原西部赛利普中新世火山岩源区:地球化学及Sr-Nd同位素制约.岩石学报, 24(2):265-278. http://www.cnki.com.cn/Article/CJFDTotal-YSXB200802009.htm

王增振, 陈宣华, 李冰, 等, 2019.甘肃合黎山古元古代正长岩的发现及其对阿拉善地块大地构造属性的启示.中国地质, 46(5):1094-1104. http://www.cnki.com.cn/Article/CJFDTotal-DIZI201905011.htm

张志强, 王凯兴, 王刚, 等, 2018.甘肃龙首山芨岭地区古生代正长岩成因及构造意义.地质论评, 64(4):1017-1029. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=dzlp201804018

赵东辉, 平先权, 郑建平, 等, 2019.西秦岭印支早期铁堂峡石英正长斑岩的地球化学特征及其地质意义.地球科学, 44(12):4203-4221. doi: 10.3799/dqkx.2019.225

赵志丹, 莫宣学, Nomade, S., 等, 2006.青藏高原拉萨地块碰撞后超钾质岩石的时空分布及其意义.岩石学报, 22(4):787-794. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98200604003

朱明田, 武广, 解洪晶, 等, 2011.新疆西天山科克赛岩体年代学、地球化学及地质意义.岩石学报, 27(10):3041-3054. http://www.wanfangdata.com.cn/details/detail.do?_type=perio&id=ysxb98201110020

Relative Articles

Supplements(1)