Citation: | LIU Jiang, LUO Yanjun, FAN Baocheng, Mustafo Gadoev. 2024. U-Pb Dating, Hf-isotopic Characteristics and Tectonic Implications of Granite, Alichur Dome, Southern Pamir, Tajikistan. Northwestern Geology, 57(6): 290-299. doi: 10.12401/j.nwg.2024027 |
Cenozoic domes separated by detachments and formed during the India-Eurasian collision, are commonly distributed in the southern Pamir. The core complex of these domes are made up of high-grade metamorphic rocks and granite. The granite mainly formed during the Late Mesozoic and minor of them formed during the Cenozoic. The granite samples gathered along the detachments and from the granite comprising the bulk Alichur dome are measured by on the LA-MC-ICP U-Pb zircon dating. The formation times of the granite are (19.30±0.36) Ma and (111.7±0.8) Ma. Hf-isotopic characteristics of zircon demonstrate the granite formed by partial melting of crust. The Cenozoic granite is probably closely associated with the structural decompression caused by the extensional decollement of the domes.
[1] | 范堡程, 孟广路, 刘明义, 等. 塔吉克斯坦成矿单元划分及其特征[J]. 地质科技情报, 2017, 36(2): 168−175. FAN Baocheng, MENG Guanglu, LIU Mingyi, et al. Division and Features of the Metallogenic Units in Tajikistan[J]. Geological Science and Technology Information,2017,36(2):168−175. |
[2] | 范堡程, 张晶, 孟广路, 等. 帕米尔构造结锂矿资源潜力评价——基于1∶100万地球化学调查[J]. 西北地质, 2022, 55(1): 156−166. FAN Baocheng, ZHANG Jing, MENG Guanglu, et al. An Assessment of Lithium Resource Potentiality in Pamir Syntax: Based on 1: 1 million Scale of Geochemical Survey[J]. Northwestern Geology,2022,55(1):156−166. |
[3] | 范堡程, 张晶, 孟广路, 等. 地球化学块体理论在塔吉克斯坦金资源潜力预测中的应用[J]. 西北地质, 2020, 53(1): 138−145. FAN Baocheng, ZHANG Jing, MENG Guanglu, et al. Application of Geochemical Blocks Theory in the Prediction of Gold Resource Potential in Tajikistan[J]. Northwestern Geology,2020,53(1):138−145. |
[4] | 洪俊, 计文化, 张海迪, 等. 帕米尔地区穆尔尕布辉长岩-闪长岩的成因: 锆石U-Pb年龄、Hf同位素及岩石地球化学证据[J]. 中国地质, 2017, 44(4): 722−736. doi: 10.12029/gc20170406 HONG Jun, JI Wenhua, ZHANG Haidi, et al. Petrogenesis of Murgab gabrro-diorite from Pamir: Evidence from zircon U-Pb dating, Hf isotopes and lithogeochemistry[J]. Geology in China,2017,44(4):722−736. doi: 10.12029/gc20170406 |
[5] | 侯可军, 李延河, 邹天人, 等. LA-MC-ICP-MS锆石Hf同位素的分析方法及地质应用[J]. 岩石学报, 2007, 23(10): 2595−2604. HOU Kejun,LI Yanhe,ZOU Tianren,et al. Laser ablation-MC-ICP-MS technique for Hf isotope microanalysis of zircon and its geological appications[J]. Acta Petrologica Sinica,2007,23(10):2595−2604. |
[6] | 李艳广, 汪双双, 刘民武, 等. 斜锆石LA-ICP-MS U-Pb定年方法及应用[J]. 地质学报, 2015, 89(12): 2400−2418. LI Yanguang,WANG Shuangshuang,LIU Minwu,et al. U-Pb Dating Study of Baddeleyite by LA-ICP-MS:Technique and Application[J]. Acta Geologica Sinica,2015,89(12):2400−2418. |
[7] | 李艳广, 靳梦琪, 汪双双, 等. LA-ICP-MS U-Pb定年技术相关问题探讨[J]. 西北地质, 2023, 56(4): 274−282. doi: 10.12401/j.nwg.2023104 LI Yanguang, JIN Mengqi, WANG Shuangshuang, et al. Exploration of Issues Related to the LA–ICP–MS U–Pb Dating Technique[J]. Northwestern Geology,2023,56(4):274−282. doi: 10.12401/j.nwg.2023104 |
[8] | 吕鹏瑞, 姚文光, 张辉善, 等. 巴基斯坦及中国邻区构造单元划分及其演化[J]. 西北地质, 2017, 50(3): 126−139. doi: 10.3969/j.issn.1009-6248.2017.03.014 LÜ Pengrui, YAO Wenguang, ZHANG Huishan, et al. Tectonic Unit Division and Geological Evolution of Pakistan and Its Adjacent Regions[J]. Northwestern Geology,2017,50(3):126−139. doi: 10.3969/j.issn.1009-6248.2017.03.014 |
[9] | 吴福元, 刘志超, 刘小驰, 等. 喜马拉雅淡色花岗岩[J]. 岩石学报, 2015, 31(1): 1−36. WU Fuyuan,LIU Zhichao,LIU Xiaochi,et al. Himalayan leucogranite: Petrogenesis and implications to orogenesis and plateau uplift[J]. Acta Petrologica Sinica,2015,31(1):1−36. |
[10] | 张海迪, 吕鹏瑞, 罗彦军, 等. 塔吉克斯坦帕米尔地区构造单元划分及其特征[J]. 地质与勘探, 2019, 55(01): 135−144. ZHANG Haidi,LÜ Pengrui,LUO Yanjun,et al. Tectonic Unit Division of the Pamir Area in Tajikistan and its Geological Characteristics[J]. Geology and Exploration,2019,55(01):135−144. |
[11] | Blichert-Toft J, Albarède F. The Lu-Hf Isotope Geochemistry of Chondrites and the Evolution of the Mantle-Crust System[J]. Earth and Planetary Science Letters,1997,148(1−2):243−258. |
[12] | Griffin W L, Pearson N J, Belousova E A, et al. The Hf isotope composition of cratonic mantle: LA-ICPMS analysis of zircon megacrysts in kimberlites[J]. Geochimica et Cosmochimica Acta, 2000, 64, 133–147. |
[13] | Hubbard M S, Grew E S, Hodges K V, et al. Neogene cooling andexhumation of upper-amphibolite facies ‘‘whiteschists’’ in the southwest Pamir Mountains, Tajikistan[J]. Tectonophysics, 1999, 305: 325 – 337. |
[14] | Meng E, Liu F L, Liu P H, et al. Petrogenesis and tectonic significance of Paleoproterozoic meta-mafic rocks from central Liaodong Peninsula, northeast China: Evidencefrom zircon U-Pb dating and in situ Lu-Hf isotopes, and whole-rock geochemistry[J]. Precambrian Research,2014,247:92−109. doi: 10.1016/j.precamres.2014.03.017 |
[15] | Ludwig K R. ISOPLOT 3.0: A Geochronological Toolkit for Microsoft Excel[A]. Berkeley Geochronology Center, California, Berkeley, 2003. |
[16] | Schmidt J, Hacker B R, Ratschbacher L, et al. Cenozoic deep crust in the Pamir [J]. Earth and Planetary Science Letters, 2011, 312, 411–421. doi: 10.1016/j.jpgl.2011.10.034. |
[17] | Schwab M, et al. (2004), Assembly of the Pamirs: Age and origin of magmatic belts from the southern Tien Shan to the southern Pamirs and their relation to Tibet. [J] Tectonics, 23, TC4002. doi:10.1029/2003TC001583. |
[18] | Sippl C, Schurr B, Tympel J, et al. Geometry of the Pamir–Hindu Kush intermediate-depth earthquakes zone from local seismic data[J]. Journal of Geophysical Research-Atmospheres, 2013,118, 1438–1457. |
[19] | Smit M A, Hacker B R, Ratschbacher L. Lu–Hf geochronol-ogy constrains slow burial of crust in active orogens: The Pamir gneiss domes[A]. European Mineral Confonrence, 2012, 1, EMC2012-706. |
[20] | Smit M A, Ratschbacher L, Kooijman E, et al. arly evolution of the Pamir deep crust from Lu-Hf and U-Pb geochronology and garnet thermometry[J]. Geology,2014,42(12):1047−1050. doi: 10.1130/G35878.1 |
[21] | Stübner K, Ratschbacher L, Rutte D, et al. The giant Shakhdaramigmatitic gneiss dome, Pamir, India–Asia collision zone: 1. Geometry and kinematics[J]. Tectonics,2013a,32:948−979. doi: 10.1002/tect.20057 |
[22] | Stübner K, Ratschbacher L, Weise C, et al. The giant Shakhdaramigmatitic gneiss dome, Pamir, India–Asia collision zone: 2 Timing of dome formation[J]. Tectonics,2013b,32:1401−1431. |
[23] | Tapponnier P, Mattauer M, Proust F, et al. Mesozoic ophiolites, sutures, and large-scale tectonic movements in Afghanistan[J]. Earth and Planetary Science Letters,1981,52:355−371. doi: 10.1016/0012-821X(81)90189-8 |
[24] | Yin A, Harrison T M. Geologic evolution of the Himalayan–Tibet orogen [J]. Annual Review of Earth and Planetary Sciences, 2000, 28, 211–280. |
[25] | Van Achterbergh E, Ryan C G, Jackson S E, et al. Data reduction software for LA-ICP-MS[A]. In: Sylvester P J (Ed.). Laser-Ablation-ICP MS in the Earth Sciences: Principles and Applications[M]. Mineralogical Society of Canada Short Course Series 29, 2001: 239–243. |
(a) Geological sketch of Pamir and (b) the geological map of Alichur dome
Photographys of granitic rocks from the Alichur dome in the views of outcrop, hand specimen and rock section
CL images of representative zircons and zircon U-Pb concordia diagram of grantic rocks from the Alichur dome
εHf-t diagram of grantic rocks from the Alichur dome