Rock Exhumation Rates in Motuo Section of Yarlung Tsangpo River: Evidence from Biotite Ar/Ar Chronology
-
摘要: 为揭示东喜马拉雅构造结及其周边区域完整地质演化过程，对采集自雅鲁藏布江墨脱段10块基岩样品进行黑云母40Ar/39Ar测年，并利用“Pecube”软件对年龄代表隆升剥露速率进行定量计算.样品黑云母40Ar/39Ar年龄范围为11.25~24.04 Ma，对应隆升剥露速率范围为0.25~0.51 km/Ma.雅鲁藏布江墨脱段地壳隆升剥露速率存在明显南北差异，北段隆升剥露速率高出约0.2 km/Ma.年代学数据及计算结果表明，与东喜马拉雅构造结内部相比，雅鲁藏布江下游墨脱段为地壳隆升剥露活动相对较弱区域.与喜马拉雅地体向拉萨地体俯冲过程相关北西、北西西走向逆断层活动，不仅在东喜马拉雅构造结内部区域发育，在其东侧雅鲁藏布江墨脱段也可能发育.Abstract: To reveal the tectonic evolution of the eastern Himalayan syntaxis and its surrounding areas, in this paper it reports 10 40Ar/39Ar ages of biotite from Motuo Section of the Yarlung Tsangpo River. It quantitatively interprets the rock's uplift and exhumation rates represented by these ages, using a modeling code "Pecube". Biotite 40Ar/39Ar ages in this paper are in the range of 11.25-24.04 Ma. Corresponding exhumation rates are in the range of 0.25-0.51 km/Ma. The rock exhumation rates in Motuo Section of the Yarlung Tsangpo River have obvious differences between northern and southern, which is characterized by the northern exhumation rates about 0.2 km/Ma higher than the southern. The ages and simulation results show that relative to the inside of the eastern Himalayan syntaxis, the exhumation rates in Motuo Section of the Yarlung Tsangpo River are lower. And the NW/NWW-trending thrust fault zones which were resulted by the collision between Himalayan terrane and Lhasa terrane, not only located in the inside of the eastern Himalayan syntaxis, but also probably located in Motuo Section of the Yarlung Tsangpo River.
-
Key words:
- eastern Himalayan syntaxis /
- Yarlung Tsangpo River /
- biotite 40Ar/39Ar /
- exhumation /
- thrust fault /
- geochronology
-
图 2 雅鲁藏布江墨脱段流域数字地貌及采样位置
Fig. 2. Digital geomorphological map of the Yarlung Tsangpo River Motuo Section and sample locations
图 3 野外露头照片
a.南段雅鲁藏布江主河段河谷样品MT⁃01采集处弱变形花岗岩；b.南段雅鲁藏布江主河段河谷花岗岩中发育北北东走向近直立脆性破裂面；c.北段雅鲁藏布江支流河谷样品MT⁃12采集处片麻岩，片麻理产状为北西西走向近直立；d.北段雅鲁藏布江支流河谷片麻岩中发育北西西走向近直立脆性破裂面；图中白色宽箭头及其内数字代表照片拍摄方向；红色线段及白色长方形内数字代表破裂面位置及产状
Fig. 3. Photographs of field outcrops
图 6 河流地貌形态样品年龄对比
a.样品实测年龄、模拟年龄、最佳隆升剥露速率对比；b.雅鲁藏布江墨脱段河流纵剖面
Fig. 6. River morphology and age contrast
图 7 东喜马拉雅构造结演化模式
a.8 Ma以前水平面大地构造框架示意图；b.8 Ma以前垂向剖面大地构造框架示意图；c.8 Ma以来水平面大地构造框架示意图；d~f.8 Ma以来垂向剖面大地构造框架示意图；HP.含高压麻粒岩透镜体高级变质杂岩；YCF.雅江峡谷逆冲断裂带；NMLF.那木拉逆冲断裂带；ANQF.阿尼桥正断层
Fig. 7. Cartoon figures of the eastern Himalayan syntaxis tectonic evolution
表 1 样品信息及年龄值
Table 1. Sample information and chronology data
样品名 经度 纬度 海拔(m) 岩性 黑云母40Ar/39Ar
坪年龄(Ma)2σ误差(Ma) MSWD值 MT-01 E95.186° N29.254° 681 黑云角闪花岗岩 20.84 0.61 0.36 MT-02 E95.251° N29.278° 727 黑云角闪花岗
闪长岩17.94 0.57 0.17 MT-03 E95.286° N29.302° 764 黑云角闪花岗
闪长岩20.00 1.10 0.11 MT-05 E95.343° N29.351° 750 黑云母闪长岩 20.16 0.33 0.64 MT-06 E95.355° N29.369° 790 花岗闪长岩 24.04 0.62 0.34 MT-09 E95.448° N29.502° 957 片麻岩 11.25 0.31 0.32 MT-10 E95.458° N29.545° 1 177 片麻岩 15.62 0.20 0.10 MT-11 E95.473° N29.594° 1 440 闪长岩 14.35 0.47 0.13 MT-12-1 E95.483° N29.645° 1 859 片麻岩 14.52 0.67 0.13 MT-12-2 E95.483° N29.645° 1 859 片麻岩 13.46 0.45 0.12 
下载: 导出CSV
表 2 样品实测年龄与模拟计算年龄
Table 2. Samples' observed ages and predicted ages
样品名 实测年龄
(Ma)模拟年龄(Ma) 最佳隆升
剥露速率
(km/Ma)VE=0.2
km/MaVE=0.25
km/MaVE=0.3
km/MaVE=0.35
km/MaVE=0.4
km/MaVE=0.45
km/MaVE=0.5
km/MaVE=0.55
km/MaMT-01 20.84 31.57 25.05 20.66 17.51 15.14 13.28 11.80 10.58 0.30 MT-02 17.94 30.29 24.02 19.81 16.78 14.49 12.71 11.28 10.10 0.33 MT-03 20 30.24 23.98 19.77 16.75 14.47 12.69 11.26 10.08 0.30 MT-05 20.16 30.27 24.01 19.79 16.76 14.48 12.70 11.27 10.09 0.30 MT-06 24.04 30.90 24.51 20.21 17.12 14.80 12.98 11.52 10.32 0.25 MT-09 11.25 30.92 24.52 20.22 17.13 14.80 12.98 11.52 10.32 0.51 MT-10 15.62 31.16 24.70 20.37 17.25 14.90 13.06 11.59 10.38 0.40 MT-11 14.35 31.64 25.08 20.67 17.50 15.11 13.24 11.75 10.52 0.42 MT-12-1 14.52 33.61 26.65 21.97 18.60 16.07 14.09 12.50 11.20 0.45 MT-12-2 13.46 33.61 26.65 21.97 18.60 16.07 14.09 12.50 11.20 0.45
下载: 导出CSV
-
[1] Anders, A.M., Roe, G.H., Hallet, B., et al., 2006. Spatial Patterns of Precipitation and Topography in the Himalaya. Special Papers-Geological Society of America, 398: 39-54. https://doi.org/10.1130/2006.2398(03) [2] Baksi, A.K., Archibald, D.A., Farrar, E., 1996. Intercalibration of 40Ar/39Ar Dating Standards. Chemical Geology, 129(3-4): 307-324. https://doi.org/10.1016/0009-2541(95)00154-9 [3] Beaumont, C., Jamieson, R.A., Nguyen, M.H., et al., 2001. Himalayan Tectonics Explained by Extrusion of a Low-Viscosity Crustal Channel Coupled to Focused Surface Denudation. Nature, 414: 738-742. https://doi.org/10.1038/414738a [4] Booth, A.L., Chamberlain, C.P., Kidd, W.S.F., et al., 2009. Constraints on the Metamorphic Evolution of the Eastern Himalayan Syntaxis from Geochronologic and Petrologic Studies of Namche Barwa. Geological Society of America Bulletin, 121(3-4): 385-407. https://doi.org/10.1130/b26041.1 [5] Bracciali, L., Najman, Y., Parrish, R.R., et al., 2015. The Brahmaputra Tale of Tectonics and Erosion: Early Miocene River Capture in the Eastern Himalaya. Earth and Planetary Science Letters, 415: 25-37. https://doi.org/10.1016/j.epsl.2015.01.022 [6] Braun, J., van der Beek, P., Valla, P., et al., 2012. Quantifying Rates of Landscape Evolution and Tectonic Processes by Thermochronology and Numerical Modeling of Crustal Heat Transport Using PECUBE. Tectonophysics, 524-525: 1-28. https://doi.org/10.1016/j.tecto.2011.12.035 [7] Burg, J.P., Nievergelt, P., Oberli, F., et al., 1998. The Namche Barwa Syntaxis: Evidence for Exhumation Related to Compressional Crustal Folding. Journal of Asian Earth Sciences, 16(2-3): 239-252. https://doi.org/10.1016/s0743-9547(98)00002-6 [8] Craw, D., Koons, P.O., Zeitler, P.K., et al., 2005. Fluid Evolution and Thermal Structure in the Rapidly Exhuming Gneiss Complex of Namche Barwa-Gyala Peri, Eastern Himalayan Syntaxis. Journal of Metamorphic Geology, 23(9): 829-845. https://doi.org/10.1111/j.1525-1314.2005.00612.x [9] Ding, L., Zhong, D.L., 1999. High Pressure Granulite Facies Metamorphism Characteristics and Tectonic Geological Significance in the Namche Barwa Region Tibet. Science in China (Series D), 29(5): 385-397(in Chinese). [10] Ding, L., Zhong, D.L., Yin, A., et al., 2001. Cenozoic Structural and Metamorphic Evolution of the Eastern Himalayan Syntaxis (Namche Barwa). Earth and Planetary Science Letters, 192(3): 423-438. https://doi.org/10.1016/s0012-821x(01)00463-0 [11] Gong, J.F., Ji, J.Q., Zhou, J., et al., 2015. Late Miocene Thermal Evolution of the Eastern Himalayan Syntaxis as Constrained by Biotite 40Ar/39Ar Thermochronology. The Journal of Geology, 123(4): 369-384. https://doi.org/10.1086/682951 [12] Govin, G., van der Beek, P., Najman, Y., et al., 2020. Early Onset and Late Acceleration of Rapid Exhumation in the Namche Barwa Syntaxis, Eastern Himalaya. Geology, 48(12): 1139-1143. https://doi.org/10.1130/g47720.1 [13] Harrison, T.M., Duncan, I., McDougall, I., 1985. Diffusion of 40Ar in Biotite: Temperature, Pressure and Compositional Effects. Geochimica et Cosmochimica Acta, 49(11): 2461-2468. https://doi.org/10.1016/0016-7037(85)90246-7 [14] King, G.E., Herman, F., Guralnik, B., 2016. Northward Migration of the Eastern Himalayan Syntaxis Revealed by OSL Thermochronometry. Science, 353(6301): 800-804. https://doi.org/10.1126/science.aaf2637 [15] Lee, H.Y., Chung, S.L., Wang, J.R., et al., 2003. Miocene Jiali Faulting and Its Implications for Tibetan Tectonic Evolution. Earth and Planetary Science Letters, 205(3-4): 185-194. https://doi.org/10.1016/s0012-821x(02)01040-3 [16] Molnar, P., England, P., 1990. Late Cenozoic Uplift of Mountain Ranges and Global Climate Change: Chicken or Egg? Nature, 346: 29-34. https://doi.org/10.1038/346029a0 [17] Mo, X.X., 2019. Magmatism and Deep Geological Process. Earth Science, 44(5): 1487-1493(in Chinese with English abatract). https://doi.org/10.3799/dqkx.2019.972 [18] Raymo, M.E., Ruddiman, W.F., 1992. Tectonic Forcing of Late Cenozoic Climate. Nature, 359: 117-122. https://doi.org/10.1038/359117a0 [19] Seward, D., Burg, J.P., 2008. Growth of the Namche Barwa Syntaxis and Associated Evolution of the Tsangpo Gorge: Constraints from Structural and Thermochronological Data. Tectonophysics, 451(1-4): 282-289. https://doi.org/10.1016/j.tecto.2007.11.057 [20] Shi, Y.F., Zheng, B.X., Su, Z., 2006. Glaciations, Glacial and Interglacial Cycles and Environment Changes in Quaternary. In: Shi, Y.F., Cui, Z.J., Su, Z., eds., The Quaternary Glaciations and Environmental Variations in China. Hebei Science and Technology Publishing House, Shijiazhuang(in Chinese). [21] Steiger, R.H., Jäger, E., 1977. Subcommission on Geochronology: Convention on the Use of Decay Constants in Geo- and Cosmochronology. Earth and Planetary Science Letters, 36(3): 359-362. https://doi.org/10.1016/0012-821s(77)90060-7 [22] Stewart, R.J., Hallet, B., Zeitler, P.K., et al., 2008. Brahmaputra Sediment Flux Dominated by Highly Localized Rapid Erosion from the Easternmost Himalaya. Geology, 36(9): 711. https://doi.org/10.1130/g24890a.1 [23] Tu, J.Y., Ji, J.Q., Gong, J.F., et al., 2016. Zircon U-Pb Dating Constraints on the Crustal Melting Event around 8 Ma in the Eastern Himalayan Syntaxis. International Geology Review, 58(1): 58-70. https://doi.org/10.1080/00206814.2015.1056255 [24] Tu, J.Y., Ji, J.Q., Sun, D.X., et al., 2015. Thermal Structure, Rock Exhumation, and Glacial Erosion of the Namche Barwa Peak, Constraints from Thermochronological Data. Journal of Asian Earth Sciences, 105: 223-233. https://doi.org/10.1016/j.jseaes.2015.03.035 [25] Wang, P., Scherler, D., Liu, Z.J., et al., 2014. Tectonic Control of Yarlung Tsangpo Gorge Revealed by a Buried Canyon in Southern Tibet. Science, 346(6212): 978-981. https://doi.org/10.1126/science.1259041 [26] Wen, D.R., Liu, D.Y., Chung, S.L., et al., 2008. Zircon SHRIMP U-Pb Ages of the Gangdese Batholith and Implications for Neotethyan Subduction in Southern Tibet. Chemical Geology, 252(3-4): 191-201. https://doi.org/10.1016/j.chemgeo.2008.03.003 [27] Xu, Q.Q., Ji, J.Q., Zhong, D.L., et al., 2020. Post-Glacial Entrenchment and Knickpoint Migration of the Yarlung Tsangpo Gorge, Southeastern Tibetan Plateau. Journal of Asian Earth Sciences, 195: 104337. https://doi.org/10.1016/j.jseaes.2020.104337 [28] Xu, Z.Q., Ji, S.C., Cai, Z.H., et al., 2012. Kinematics and Dynamics of the Namche Barwa Syntaxis, Eastern Himalaya: Constraints from Deformation, Fabrics and Geochronology. Gondwana Research, 21(1): 19-36. https://doi.org/10.1016/j.gr.2011.06.010 [29] Yang, R., Herman, F., Fellin, M.G., et al., 2018. Exhumation and Topographic Evolution of the Namche Barwa Syntaxis, Eastern Himalaya. Tectonophysics, 722: 43-52. https://doi.org/10.1016/j.tecto.2017.10.026 [30] Yin, A., Harrison, T.M., 2000. Geologic Evolution of the Himalayan-Tibetan Orogen. Annual Review of Earth and Planetary Sciences, 28(1): 211-280. https://doi.org/10.1146/annurev.earth.28.1.211 [31] Zeitler, P.K., Meltzer, A.S., Brown, L., et al., 2014. Tectonics and Topographic Evolution of Namche Barwa and the Easternmost Lhasa Block, Tibet. Geological Society of America Special Papers, 507(23). https://doi.org/10.1130/2014.2507(02) [32] Zeitler, P.K., Meltzer, A.S., Koons, P.O., et al., 2001. Erosion, Himalayan Geodynamics, and the Geomorphology of Metamorphism. GSA Today, 11(1): 4-9. doi: 10.1130/1052-5173(2001)011<0004:EHGATG>2.0.CO;2 [33] Zhang, J.J., Ji, J.Q., Zhong, D.L., et al., 2004. Structural Pattern of Eastern Himalayan Syntaxis in Namjagbarwa and Its Formation Process. Science in China: Earth Sciences, 47(2): 138-150. https://doi.org/10.1360/02yd0042 [34] Zhang, P.Z., Molnar, P., Downs, W.R., 2001. Increased Sedimentation Rates and Grain Sizes 2-4 Myr ago Due to the Influence of Climate Change on Erosion Rates. Nature, 410: 891-897. https://doi.org/10.1038/35073504 [35] Zhang, Z.M., Dong, X., Santosh, M., et al., 2012. Petrology and Geochronology of the Namche Barwa Complex in the Eastern Himalayan Syntaxis, Tibet: Constraints on the Origin and Evolution of the North-Eastern Margin of the Indian Craton. Gondwana Research, 21(1): 123-137. https://doi.org/10.1016/j.gr.2011.02.002 [36] Zhang, Z.G., Liu, Y.H., Wang, T.W., et al., 1992. Geology of the Namche Barwa Region. Science Press, Beijing(in Chinese). [37] Zhang, Z.M., Ding, H.X., Dong, X., et al., 2019. Two Contrasting Eclogite Types in the Himalayan Orogen and Differential Subduction of Indian Continent. Earth Science, 44(5): 1602-1619(in Chinese with English abatract). [38] Zhong, D.L., Ding, L., 1995. High Pressure Granulite Found in the Namche Barwa Region Tibet. Chinese Science Bulletin, 40(14): 1343(in Chinese). doi: 10.1360/csb1995-40-14-1343 [39] 丁林, 钟大赉, 1999. 西藏南迦巴瓦峰地区高压麻粒岩相变质作用特征及其构造地质意义. 中国科学(D辑), 29(5): 385-397. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK199905000.htm [40] 莫宣学, 2019. 岩浆作用与地球深部过程. 地球科学, 44(5): 1487-1493. doi: 10.3799/dqkx.2019.972 [41] 施雅风, 郑本兴, 苏珍, 2006. 第四纪冰川、冰期间冰期旋回与环境变化. 见: 施雅风, 崔之久, 苏珍, 编. 中国第四纪冰川与环境变化. 石家庄: 河北科学技术出版社. [42] 章振根, 刘玉海, 王天武, 等, 1992. 南迦巴瓦峰地区地质. 北京: 科学出版社. [43] 张泽明, 丁慧霞, 董昕, 等, 2019. 喜马拉雅造山带两种不同类型榴辉岩与印度大陆差异性俯冲. 地球科学, 44(5): 1602-1619. doi: 10.3799/dqkx.2019.040 [44] 钟大赉, 丁林, 1995. 西藏南迦巴瓦峰地区发现高压麻粒岩. 科学通报, 40(14): 1343. doi: 10.3321/j.issn:0023-074X.1995.14.029 -
点击查看大图
图(7) / 表(2)
计量
- 文章访问数: 547
- HTML全文浏览量: 157
- PDF下载量: 55
- 被引次数: 0
