大悟杂岩的形成和抬升时代及其地质意义

doi:10.13278/j.cnki.jjuese.201701113

摘要/Abstract

摘要： 大悟杂岩位于大别山西段，主体为花岗质片麻岩。为了限定其形成与变形过程，本文综合运用锆石U-Pb法和白云母⁴⁰Ar/³⁹Ar法进行年代学研究。锆石U-Pb LA-ICP-MS法对这些花岗质片麻岩定年结果显示：锆石的Th/U值为0.79~4.29，属于典型的岩浆锆石特征；²⁰⁶Pb/²³⁸U的加权平均年龄为（810±63）Ma（n=12，MSWD=0.021），代表这些花岗质片麻岩的形成时代。大悟杂岩核部花岗质片麻岩的白云母坪年龄为（210.5±1.4）Ma，相应的等时线年龄为（211.6±2.5）Ma。这些新的研究结果支持以下两点认识：大悟杂岩中的花岗质片麻岩形成于新元古代，而不是白垩纪；这些前寒武纪岩石的构造抬升过程发生在三叠纪晚期（211 Ma）。由于西大别晚三叠世构造与高压-超高压变质岩的出露过程有关，因此,大悟杂岩的变形与高压-超高压变质岩的抬升之间的关系就成为一个耐人寻味的科学问题。同时，由于大悟杂岩中的多数构造面理和线理形成于区域高压-超高压变质作用之后，据此推断西大别三叠纪晚期的变形发生在造山晚期-后造山背景下，伴随着地壳和岩石圈的大规模伸展与减薄。

关键词: 大悟杂岩, 花岗质片麻岩, 锆石U-Pb定年, ⁴⁰Ar-³⁹Ar定年, 陆内变形

Abstract: Dawu complex is located in the western part of the Dabie orogenic belt. The complex is mainly composed of gneissic granite. To constrain the timing of the formation and deformation processes of the complex, a set of integrated zircon U-Pb and muscovite ⁴⁰Ar-³⁹Ar dating were carried out. The conducted zircon U-Pb LA-ICP-MS isotopic dating of the gneissic granites from the complex showed Th/U ratios in the range of 0.79-4.29 indicating the zircon is a typical magmatic mineral. The weighted mean ²⁰⁶Pb/²³⁸U age is(810±63)Ma (n=12, MSWD=0.021), which is considered to be the formation age of the gneiss. The ⁴⁰Ar/³⁹Ar dating of muscovite from the gneissic granites in the central part of Dawu complex yields a plateau age of (210.5±1.4) Ma and an isochron age of (211.6±2.5) Ma. The new dating results support that:(1) The strongly deformed magmatic rocks in the Dawu complex were formed in the Neoproterozoic rather than Cretaceous, (2) Large scale crustal deformation and exhumation of the Precambrian rocks mainly occurred in Late Triassic (211 Ma). Since the Late Triassic tectonic processes were related to exhumation of the HP-UHP metamorphic rocks in western Dabie orogen, it is worth investigating the relationship between the formation of the Dawu complex and the exhumation of the HP-UHP metamorphic rock in the study area. Meanwhile, most of the foliations and lineations in the Dawu complex formed after the regional HP-UHP metamorphism, we therefore infer that the Late Triassic deformation occurred in the geodynamic settings of late to post-orogeny, and might be accompanied by large scale crustal extension and lithospheric thinning.

Key words: Dawu complex, gneissic granites, zircon U-Pb dating, ⁴⁰Ar-³⁹Ar dating, crustal deformation

中图分类号:

P588.1

崔建军, 王艳红, 郑光高, 施炜, 马立成. 大悟杂岩的形成和抬升时代及其地质意义[J]. 吉林大学学报(地球科学版), 2017, 47(1): 139-153.

Cui Jianjun, Wang Yanhong, Zheng Guanggao, Shi Wei, Ma Licheng. The Timing of the Formation and Exhumation of the Dawu Complex in West Dabie Orogen, East China, and Its Geological Significance[J]. Journal of Jilin University(Earth Science Edition), 2017, 47(1): 139-153.

参考文献

[1] Meng Qingren, Zhang Guowei. Geologic Framework and Tectonic Evolution of the Qinling Orogen, Central China[J]. Tectonophysics, 2000, 323:183-196.
[2] Dong Shuwen, Gao Ri, Cong Bailin, et al. Crustal Structure of the Southern Dabie Ultrahigh-Pressure Orogeny and Yangtze Foreland from Deep Seismic Reflection Profiling[J]. Terra Nova, 2004, 16(6):319-324.
[3] Li Sanzhong, Kusky T M, Liu Xiaochun, et al. Two-Stage Collision-Related Extrusion of the Western Dabie HP-UHP Metamorphic Terranes, Central China:Evidence from Quartz C-Axis Fabrics and Structures[J]. Gondwana Research, 2009, 16:294-309.
[4] Lin Wei, Shi Yonghong, Wang Qingchen. Exhumation Tectonics of the HP-UHP Orogenic Belt in Eastern China:New Structural-Petrological Insights from the Tongcheng Massif, Eastern Dabieshan[J].Lithos, 2009, 109(3/4):285-303.
[5] 刘鑫, 李三忠, 索艳慧, 等. 桐柏碰撞造山带及其邻区变形特征与构造格局[J]. 岩石学报, 2010, 26(4):1289-1302. Liu Xin, Li Sanzhong, Suo Yanhui, et al. Tectonic Outline and Structural Stale of the Tongbai Collisional Orogen and Its Neighbors[J]. Acta Petrologica Sinica, 2010, 26(4):1289-1302.
[6] 王国灿, 杨巍然. 大别山核部罗田穹窿(隆)形成的构造及年代学证据[J]. 地球科学:中国地质大学学报, 1996, 21(5):524-528. Wang Guocan, Yang Weiran. Structural and Chronological Evidence of the Luotian Dome in the Core of the Eastern Dabie Mountains, Central China[J]. Earth Science:Journal of China University of Geosciences, 1996, 21(5):524-528.
[7] 索书田, 钟增球, 游振东. 大别苏鲁超高压高压变质带伸展构造格架及其动力学意义[J]. 地质学报, 2001, 75(1):14-24. Suo Shutian, Zhong Zengqiu,You Zhendong. Extentional Tectonic Framework of the Dabie-Sulu UHP-HP Metamorphic Belt, Central China, and Its Geodynamical Significance[J]. Acta Geologica Sinica, 2001, 75(1):14-24.
[8] Liu Xiaochun, Jahn Borming, Cui Jianjun, et al. Tria-ssic Retrograded Eclogites and Cretaceous Gneissic Granites in the Tongbai Complex, Central China:Implications for the Architecture of the HP/UHP Tongbai-Dabie-Sulu Collision Zone[J]. Lithos, 2010, 119:211-237.
[9] Dong Yunpeng, Liu Xiaoming, Santosh M,et al. Neo-Proterozoic Subduction Tectonics of the Northwestern Yangtze Block in South China:Constrains from Zircon U-Pb Geochronology and Geochemistry of Mafic Intrusions in the Hannan Massif[J]. Precambrian Research, 2011, 189:66-90.
[10] 董树文, 胡健民, 李三忠, 等. 大别山侏罗纪变形及其构造意义[J].岩石学报, 2005, 21(4):1189-1194. Dong Shuwen, Hu Jianmin, Li Sanzhong, et al. The Jurassic Deformation in the Dabie Mountains and Its Tectonic Significances[J]. Acta Petrologica Sinica, 2005, 21(4):1189-1194.
[11] 董树文, 胡健民, 施炜, 等. 大巴山侏罗纪叠加褶皱与侏罗纪前陆[J]. 地球学报,2006, 27(5):403-410. Dong Shuwen, Hu Jianmin, Shi Wei, et al. Jurassic Superposed Folding and Jurassic Foreland in the Daba Mountain, Central China[J]. Acta Geoscientia Sinica, 2006, 27(5):403-410.
[12] Zheng Yongfei. A Perspective View on Ultrahigh-Pressure Metamorphism and Continental Collision in the Dabie-Sulu Orogenic Belt[J]. Chinese Science Bulletin, 2008, 53:3081-3104.
[13] Liu Shaofeng, Zhang Guowei, RITTS B D, et al. Tracing Exhumation of the Dabie Shan Ultrahigh-Pressure Metamorphic Complex Using the Sedimentary Record in the Hefei Basin, China[J]. Geological Society of America Bulletin, 2009, 122:198-218.
[14] Li Sanzhong, Zhao Guochun, Dai Liming, et al. Mesozoic Basins in Eastern China and Their Bearing on the Deconstruction of the North China Craton[J]. Journal of Asian Earth Sciences, 2012, 47:64-79.
[15] Webb L E, Hacker B R, Ratschbacher L, et al. Thermochronologic Constraints on Deformation and Cooling History of High- and Ultrahigh-Pressure Rocks in the Qinling-Dabie Orogen, Eastern China[J]. Tectonics, 1999, 18:621-638.
[16] Webb L E, Ratschbacher L, Hacker B R, et al. Kinematics of Exhumation of High- and Ultrahigh-Pressure Rocks in the Hong'an and Tongbai Shan of the Qinling-Dabie Collisional Orogen, Eastern China[C]//Hendrix M S, Davis G A.Paleozoic and Mesozoic Tectonic Evolution of Central Asia:From Continental Assembly to Intracontinental Deformation Memoir 194. Boulder, Colorado:Geological Society of America, 2001:231-245.
[17] Ratschbacher L, Franz L, Enkelmann E, et al. The Sino-Korean-Yangtze Suture, the Huwan Detachment, and the Paleozoic-Tertiary Exhumation of (Ultra)High-Pressure Rocks Along the Tongbai-Xinxian-Dabie Mountains[C]//Hacker B R, McClelland W C, Liou J G. Ultrahigh-Pressure Metamorphism:Deep Continental Subduction.[S.l.]:Geological Society of America Special Paper, 2006, 403:45-75.
[18] Cui Jianjun, Liu Xiaochun, Dong Shuwen, et al.U-Pb and ⁴⁰Ar/³⁹Ar Geochronology of the Tongbai Complex, Central China:Implications for Cretaceous Exhumation and Lateral Extrusion of the Tongbai-Dabie HP/UHP Terrane[J]. Journal of Asian Earth Sciences, 2012, 47:155-170.
[19] Liu Xiaochun. High-P Metamorphic Belt in Central China and Its Possible Eastward Extension to Korea[J]. Journal of Petroloical Society of Korea,1993, 2:9-18.
[20] Liu Xiaochun, Wei Chunjing, Li Sanzhong, et al. Thermobaric Structure of a Traverse Across Western Dabieshan:Implications for Collision Tectonics Between the Sino-Korean and Yangtze Cratons[J]. Journal of Metamorphic Geology, 2004, 22:361-379.
[21] Liu Xiaochun, Jahn Borming, Liu Dunyi, et al. SHRIMP U-Pb Zircon Dating of a Metagabbro and Eclogites from Western Dabieshan (Hong'an Block), China, and Its Tectonic Implications[J]. Tectonophysics, 2004, 394:171-192.
[22] Ratschbacher L, Hacker B R, Webb L E, et al. Exhumation of the Ultrahigh-Pressure Continental Crust in East Central China:Cretaceous and Cenozoic Unroofing and the Tan-Lu Fault[J]. Journal of Geophysical Research Atmospheres, 2000, 105:13303-13338.
[23] 刘晓春, 娄玉行, 董树文. 桐柏山地区低温榴辉岩变质作用的P-T轨迹[J]. 岩石学报, 2005, 21(4):1081-1093. Liu Xiaochun, Lou Yuxing, Dong Shuwen. P-T Path of Low-Temperature Eclogites from the Tong-baishan Area[J]. Acta Petrologica Sinica, 2005, 21(4):1081-1093.
[24] Kr ner A, Zhang Guowei,Sun Y. Granulites in the Tongbai Area, Qinling Belt, China:Geochemistry, Petrology, Single Zircon Geochronology, and Implications for the Tectonic Evolution of Eastern Asia[J]. Tectonics, 1993, 12:245-255.
[25] 索书田, 桑隆康, 韩郁菁, 等. 大别山前寒武纪变质岩石学与构造学[M]. 武汉:中国地质大学出版社, 1993:1-259. Suo Shutian, Sang Longkang, Han Yujing, et al. The Petrology and Tectonics in Dabie Precambrian Metamorphic Terranes, Central China[M]. Wuhan:China University of Geosciences Press, 1993:1-259.
[26] Liu Xiaochun, Jahn Borming, Dong Shuwen, et al. High-Pressure Metamorphic Rocks from Tongbaishan, Central China:U-Pb and ⁴⁰Ar/³⁹Ar Age Constraints on the Provenance of Protoliths and Timing of Metamorphism[J]. Lithos, 2008, 105(3/4):301-318.
[27] 宋彪, 张玉海, 万俞生, 等. 锆石SHRIMP样品靶制作、年龄测定及有关现象讨论[J]. 地质论评, 2002, 5(增刊):26-30. Song Biao, Zhang Yuhai, Wan Yusheng, et al. Mount Making and Procedure of the SHRIMP Dating[J]. Geological Review, 2002, 5(Sup.):26-30.
[28] Yuan Honglin, Gao Shan, Liu Xiaoming, et al. Acc-urate U-Pb Age and Trace Element Determinations of Zircon by Laser Ablation-Inductively Coupled Plasma Mass Spectrometry, Geostands[J].Newsletter, 2004, 28:353-370.
[29] Ludwig K R. Users Manual for Isoplot/Ex (rev. 2.49):A Geochronological Toolkit for Microsoft Excel[Z]. Berkeley Geochronology Center,Special Publication, 2001(1a):55.
[30] 陈文, 张彦, 张岳桥, 等. 青藏高原东南缘晚新生代幕式抬升作用的Ar-Ar热年代学证据[J].岩石学报, 2006, 22(4):867-872. Chen Wen, Zhang Yan, Zhang Yueqiao, et al. Late Cenozoic Episodic Uplifting in Southeastern Part of the Tibetan Plateau-Evidence from Ar-Ar Thermocronology[J]. Acta Petrologica Sinica, 2006, 22(4):867-872.
[31] 张彦, 陈文, 陈克龙, 等. 成岩混层(I/S)Ar-Ar年龄谱型及³⁹Ar核反冲丢失机理研究:以浙江长兴地区P-T界线黏土岩为例[J]. 地质论评, 2006, 52(4):556-561. Zhang Yan, Chen Wen, Chen Kelong, et al. Study on the Ar-Ar Age Spectrum of Diagenetic I/S and the Mechanism of ³⁹Ar Recoil Loss-Examples from the Clay Minerals of P-T Boundary in Changxing, Zhejiang Province[J].Geological Review, 2006, 52(4):556-561.
[32] Li Zhengxiang, Li Xianhua, Kinny P, et al. The Breakup of Rodinia:Did It Start with a Mantle Plume Beneath South China[J]. Earth and Planetary Science Letters, 1999, 173:171-181.
[33] Li Xianhua, Li Wuxian, Li Zhengxiang, et al. 850-790 Ma Bimodal Volcanic and Intrusive Rocks in Northern Zhejiang, South China:A Major Episode of Continental Rift Magmatism During the Breakup of Rodinia[J]. Lithos, 2008, 102(1/2):341-357.
[34] Zhou Meifu, Yan Danping, Kennedy A K, et al. SHRIMP U-Pb Zircon Geochronological Along the Western Margin of the Yangtze Block, South China[J]. Earth Planetary Science Letters, 2002, 196(1/2):51-67.
[35] 崔建军, 胡健民, 刘晓春. 桐柏地区高压变质地体在地壳中的抬升机制[J].岩石学报, 2009, 25(9):2165-2176. Cui Jianjun, Hu Jianmin, Liu Xiaochun,et al. Exhumation of High-Pressure Metamorphic Terrane at the Crustal Levels in the Tongbai Area, Central China[J]. Acta Petrologica Sinica, 2009, 25(9):2165-2176.
[36] Wu Yuanbao, Hanchar J M, Gao Shan, et al. Age and Nature of Eclogites in the Huwan Shear Zone, and the Multi-Stage Evolution of the Qinling-Dabie-Sulu Orogen, Central China[J].Earth and Planetary Science Letters, 2009, 277:345-354.
[37] Dong Shuwen, Zhang Yueqiao, Long Changxing, et al. Jurassic Tectonic Revolution in China and New Interpretation of the "Yanshan Movement"[J]. Acta Geologica Sinica, 2008, 82:334-347.
[38] 杨海斌, 田小波, 白志明, 等.浅谈中国大陆东缘中生代地质演化与泛太平洋板块活动的关系[J]. 吉林大学学报(地球科学版), 2016, 46(3):781-797. Yang Haibin, Tian Xiaobo, Bai Zhiming, et al. Discussion on the Relationship Between Pan Pacific Plate Movement and Mesozoic Geological Evolution of Eastern Chinese Continent[J]. Journal of Jilin University (Earth Science Edition), 2016, 46(3):781-797.

Metrics

Viewed

Full text

Abstract

Cited

Shared

Discussed