Geochemistry and detrital zircon U-Pb geochronology of the Jurassic Ridang Formation in the southern Tibet and its tectonic implications
-
摘要:
喜马拉雅东段印度被动大陆边缘沉积的中—新生界地层是研究新特提斯大洋演化的重要载体。本文对西藏山南市错那县曲卓木乡的下侏罗统日当组粉砂岩和页岩进行碎屑锆石U-Pb定年和全岩地球化学分析。其碎屑锆石年龄有两个峰值区间，分别是546~496 Ma和952~853 Ma，峰值年龄分别为516 Ma和926 Ma，最年轻年龄为292.5±5.5 Ma。日当组的Al2O3含量较高，平均值为20.8%，而CaO、Na2O和K2O含量均较低（0.4%~4.0%），表明日当组富含粘土矿物，其物源区成分成熟度高，风化强，代表沉积物的再循环以及构造静止期或者克拉通环境。日当页岩轻稀土元素富集，重稀土元素亏损，Eu负异常明显。本文综合古地理环境，认为日当组物质来源主要为冈瓦纳大陆北缘的印度板块和澳大利亚板块，构造背景为稳定的被动大陆边缘。
-
关键词:
- 特提斯喜马拉雅 /
- 日当组 /
- 碎屑锆石U-Pb年代学 /
- 砂岩地球化学 /
- 大地构造背景
Abstract:The Mesozoic-Cenozoic strata deposited in the passive continental margin of India in the eastern Himalayas are important carriers for the study of the evolution of the Neo-Tethyan Ocean. In this paper, detrital zircon U-Pb dating and whole-rock geochemical analysis of the Lower Jurassic Ridang Formation siltstone and shale in Quzhuomu Township, Cuona County, Shannan City, Tibet Autonomous Region have been carried out. The detrital zircons have two peak ages, of 496-546 Ma and 853-952 Ma, with the peak ages of 516 Ma and 926 Ma, respectively, and the youngest age of 292.5±5.5 Ma. The content of Al2O3 in the Ridang Formation is high, with an average of 20.8%, while the contents of CaO, Na2O and K2O are low (0.4%-4.0%), indicating that the Ridang Formation is rich in clay minerals. The source area has high compositional maturity and strong weathering, which represents the recycling of sediments and the tectonic quietness or cratonic environment. The Ridang shale is enriched in light rare earth elements (LREEs) and depleted in heavy rare earth elements (HREEs), and the negative Eu anomaly is obvious. Based on the paleogeographic environment, it is considered that the material of Ridang Formation is mainly derived from the Indian plate and the Australian plate on the northern margin of Gondwana continent, and the tectonic background is a stable passive continental margin.
-
-
图 1 喜马拉雅研究区地质构造简图（据Cao et al., 2021修改）
Figure 1.
图 5 错那县下侏罗统日当组岩石类型和风化程度图解（底图据Herron, 1988, McLennan et al., 1993, Nesbitt and Young, 1982）
Figure 5.
图 6 错那县下侏罗统日当组稀土和微量元素标准化蛛网图 （球粒陨石和原始地幔值引用自Sun and McDonough, 1989）
Figure 6.
图 7 错那县日当组源岩类型和构造背景判别图解 （底图引用自Bhatia and Crook, 1986, Verma and Armstrong-Altrin, 2013, Wang et al., 2012）
Figure 7.
图 8 研究区周缘板块和地体碎屑锆石U-Pb年龄直方图 （据Cao et al., 2018修改）
Figure 8.
图 9 藏南早侏罗世古地理位置复原图 （据Li et al., 2016修改）
Figure 9.
-
[1] Bhatia M R, Crook K A W, 1986. Trace element characteristics of graywackes and tectonic setting discrimination of sedimentary basins[J]. Contributions to Mineralogy and Petrology, 92（2）: 181-193. doi: 10.1007/BF00375292
[2] Cao H W, Huang Y, Li G M, et al. , 2018. Late Triassic sedimentary records in the northern Tethyan Himalaya: tectonic link with Greater India[J]. Geoscience Frontiers, 9（1）: 273-291. doi: 10.1016/j.gsf.2017.04.001
[3] Cao H W, Li G M, Zhang R Q, et al. , 2021. Genesis of the Cuonadong tin polymetallic deposit in the Tethyan Himalaya: Evidence from geology, geochronology, fluid inclusions and multiple isotopes[J]. Gondwana Research, 92: 72-101. doi: 10.1016/j.gr.2020.12.020
[4] Cao H W, Zhang Y H, Santosh M, et al. , 2019. Petrogenesis and metallogenic implications of Cretaceous magmatism in Central Lhasa, Tibetan plateau: a case study from the Lunggar Fe skarn deposit and perspective review[J]. Geological Journal, 54（4）: 2323-2346. doi: 10.1002/gj.3299
[5] 曹华文, 李光明, 张林奎, 等, 2020. 西藏山南列麦始新世花岗岩独居石U-Th-Pb年龄及地质意义[J]. 沉积与特提斯地质, 40（2）: 31-42
Cao H W, Li G M, Zhang L K, et al. , 2020. Monazite U-Th-Pb age of Liemai Eocene granites in the southern Tibet and its geological implications[J]. Sedimentary Geology and Tethyan Geology, 40（2）: 31-42.
[6] 曹华文, 李光明, 张林奎, 等, 2022. 喜马拉雅淡色花岗岩成因与稀有金属成矿潜力[J]. 沉积与特提斯地质, 42（2）: 189-211
Cao H W, Li G M, Zhang L K, et al. , 2022. Genesis of Himalayan leucogranite and its potentiality of rare-metal mineralization[J]. Sedimentary Geology and Tethyan Geology, 42 （2 ）: 189-211.
[7] Chen G, Robertson A H F, 2020. User’s guide to the interpretation of sandstones using whole-rock chemical data, exemplified by sandstones from Triassic to Miocene passive and active margin settings from the Southern Neotethys in Cyprus[J]. Sedimentary Geology, 400: 105616. doi: 10.1016/j.sedgeo.2020.105616
[8] Cox R, Lowe D R, Cullers R L, 1995. The influence of sediment recycling and basement composition on evolution of mudrock chemistry in the southwestern United States[J]. Geochimica et Cosmochimica Acta, 59（14）: 2919-2940. doi: 10.1016/0016-7037(95)00185-9
[9] Han Z, Hu X, Boudagher-Fadel M, et al. , 2021. Early Jurassic carbon-isotope perturbations in a shallow-water succession from the Tethys Himalaya, southern hemisphere[J]. Newsletters on Stratigraphy, 54（4）: 461-481. doi: 10.1127/nos/2021/0650
[10] Harnois L, 1988. The CIW index: A new chemical index of weathering[J]. Sedimentary Geology, 55（3–4）: 319-322. doi: 10.1016/0037-0738(88)90137-6
[11] Herron M M, 1988. Geochemical classification of terrigenous sands and shales from core or log data[J]. Journal of Sedimentary Research, 58（5）: 820-829.
[12] 胡修棉, 2015. 东特提斯洋晚中生代—古近纪重大事件研究进展[J]. 自然杂志, 37（2）: 93-102
Hu X M, 2015. Overview of the Late Mesozoic Paleogene major paleoceanographic and geological events in Eastern Tethyan Ocean[J]. Chinese Journal of Nature, 37（2）: 93-102.
[13] 中国科学院青藏高原综合科学考察队, 1984. 西藏地层[M]. 北京: 科学出版社.
Integrated Scientific Expedition to the Qinghai-Tibet Plateau, Chinese Academy of Sciences, 1984. Tibetan stratigraphy[M]. Beijing: Science Press.
[14] Jadoul F, Berra F, Garzanti E, 1998. The Tethys Himalayan passive margin from Late Triassic to Early Cretaceous （South Tibet）[J]. Journal of Asian Earth Sciences, 16（2–3）: 173-194. doi: 10.1016/S0743-9547(98)00013-0
[15] Leeder M R, 2011. Tectonic sedimentology: sediment systems deciphering global to local tectonics[J]. Sedimentology, 58（1）: 2-56. doi: 10.1111/j.1365-3091.2010.01207.x
[16] 李璞, 1955. 西藏东部地质的初步认识[J]. 科学通报, 62（7）: 62-71+52
Li P, 1955. Preliminary understanding of the geology of eastern Tibet [J]. Chinese Science Bulletin, 62（7）: 62-71+52.
[17] Li Z, Lippert P, Ding L, et al. , 2016. Paleomagnetic constraints on the Mesozoic drift of the Lhasa terrane （Tibet） from Gondwana to Eurasia[J]. Geology, 44（9）: 727-730. doi: 10.1130/G38030.1
[18] 刘宝珺, 余光明, 徐强, 等, 1993. 雅鲁藏布中新生代深水沉积盆地形成和演化（Ⅰ）——喜马拉雅造山带沉积特征及演化[J]. 岩相古地理, 13（1）: 32-49
Liu B J, Yu G M, Xu Q, et al. , 1993. Formation and evolution of the Mesozoic and Cenozoic deep-water sedimentary basins along the Yarlung Zangbo River（I）: sedimentary characteristics and evolution of the Himalayan orogenic zone[J]. Sedimentary Facies and Palaeogeography, 13（1）: 32-49.
[19] Liu G, Einsele G, 1999. Jurassic sedimentary facies and paleogeography of the former Indian passive margin in southern Tibet[J]. Geological Society of America Special Papers, 328: 75-108.
[20] 毛帆, 裴先治, 李瑞保, 等, 2021. 扬子板块西北缘碧口微地块南华系碎屑锆石U-Pb年龄及其物源示踪[J]. 沉积与特提斯地质, 41（1）: 41 − 57
Mao F, Pei X Z, Li R B, et al., 2021. The LA-ICP-MS U-Pb dating of detrital zircons from the Nanhua System in Bikou Terrane, northwestern margin of Yangtze Block[J]. Sedimentary Geology and Tethyan Geology, 41C 1）: 41 − 57.
[21] McLennan S M, Hemming S, McDaniel D K, et al. , 1993. Geochemical approaches to sedimentation, provenance, and tectonics[J]. Geological Society of America Special Papers, 284: 21-40.
[22] Meng Z, Wang J G, Garzanti E, et al. , 2021. Late Triassic rifting and volcanism on the northeastern Indian margin: A new phase of Neo-Tethyan seafloor spreading and its paleogeographic implications[J]. Palaeogeography, Palaeoclimatology, Palaeoecology, 570: 110367.
[23] Nesbitt H W, Young G M, 1982. Early Proterozoic climates and plate motions inferred from major element chemistry of lutites[J]. Nature, 299（5885）: 715-717. doi: 10.1038/299715a0
[24] Neupane B, Zhao J, Allen C M, et al. , 2020. Provenance of Jurassic-Cretaceous Tethyan Himalayan sequences in the Thakkhola Section- Nepal, inferring pre-collisional tectonics of the central Himalaya[J]. Journal of Asian Earth Sciences, 192: 104288. doi: 10.1016/j.jseaes.2020.104288
[25] 潘桂棠, 王立全, 耿全如, 等, 2020. 班公湖—双湖—怒江—昌宁—孟连对接带时空结构——特提斯大洋地质及演化问题[J]. 沉积与特提斯地质, 40（3）: 1-19
Pan G T, Wang L Q, Geng Q R, et al. , 2020. Space-time structure of the Bangonghu-Shuanghu-Nujiang-Changning-Menglian Mega-suture zone: A discussion on geology and evolution of the Tethys Ocean[J]. Sedimentary Geology and Tethyan Geology, 40（3）: 1-19.
[26] Sun S S, McDonough W F, 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes[J]. Geological Society, London, Special Publications, 42（1）: 313-345. doi: 10.1144/GSL.SP.1989.042.01.19
[27] 西藏自治区地质矿产局, 1993. 中华人民共和国地质矿产部地质专报 1 区域地质 第31号 西藏自治区区域地质志[M]. 北京: 地质出版社.
Tibet Autonomous Region Bureau of Geology and Mineral Resources, 1993. Geological Special Report of the Ministry of Geology and Mineral Resources of the People’s Republic of China 1 Regional Geology No. 31 Regional geology of Tibet Autonomous Region[M]. Beijing: Geological Publishing House, : 1 − 707.
[28] Verma S P, Armstrong-Altrin J S, 2013. New multi-dimensional diagrams for tectonic discrimination of siliciclastic sediments and their application to Precambrian basins[J]. Chemical Geology, 355: 117-133. doi: 10.1016/j.chemgeo.2013.07.014
[29] 王乃文, 1983. 中国侏罗纪特提斯地层学问题[J]. 青藏高原地质文集, 2（6）: 62-86
Wang N W, 1983. The Tethyan Jurassic stratigraphy of China （in Chinese）[J]. Contribution to the Geology of the Qinghai-Xizang （Tibet） Plateau, 2（6）: 62-86.
[30] Wang W, Zhou M-F, Yan D-P, et al. , 2012. Depositional age, provenance, and tectonic setting of the Neoproterozoic Sibao Group, southeastern Yangtze Block, South China[J]. Precambrian Research, 192: 107-124.
[31] 王义刚, 王玉净, 吴浩若, 1976. 西藏南部加不拉组问题的讨论及隆子地区下侏罗统的发现[J]. 地质科学, 11（2）: 149-156
Wang Y G, Wang Y J, Wu H R, 1976. Discussion on the Jiabula Formation and the discovery of Longzi Lower Jurassic in Southern Xizang, China[J]. Chinese Journal of Geology（Scientia Geologica Sinica）, 11（2）: 149-156.
[32] 夏代祥, 刘世坤, 1997. 西藏自治区岩石地层[M]. 武汉: 中国地质大学出版社.
Xia D X, Liu S K, 1997. Stratigraphy （Lithostratic） of Xizang Autonomous Region [M]. Wuhan: China University of Geosciences Press.
[33] 徐亚军, 杜远生, 杨江海, 2007. 沉积物物源分析研究进展[J]. 地质科技情报, 26（3）: 26-32
Xu Y J, Du Y S, Yang J H, 2007. Prospects of Sediment Provenance Analysis[J]. Geological Science and Technology Information, 26（3）: 26-32.
[34] 许志琴, 杨经绥, 梁凤华, 等, 2005. 喜马拉雅地体的泛非-早古生代造山事件年龄记录[J]. 岩石学报, 21（1）: 3 − 14.
Xu Z Q, Yang J S, Liang F H, et al., 2005. Pan-African and Early Paleozoic orogenic events in the Himalaya terrane: Inference from SHRIMP U-Pb zircon ages （in Chinese with English abstract）[J]. Acta Petrologica Sinica, 21: 1 − 12.
[35] 张士贞, 秦雅东, 李勇, 等, 2021. 西藏许如错地区洁居纳卓组碎屑锆石U-Pb年龄及其地质意义[J]. 沉积与特提斯地质, 41（1）: 24-32
Zhang S Z, Qin Y D, Li Y, et al. , 2021. U-Pb dating for detrital zircons from the Jiejunazhuo Formation in Xuru Co area and its geological significances[J]. Sedimentary Geology and Tethyan Geology, 41（1）: 24-32.
[36] Zhu D C, Chung S L, Mo X X, et al. , 2009. The 132 Ma Comei-Bunbury large igneous province: Remnants identified in present-day southeastern Tibet and southwestern Australia[J]. Geology, 37（7）: 583-586. doi: 10.1130/G30001A.1
-
下载:
图(9)
计量
- 文章访问数: 761
- PDF下载数: 1
- 施引文献: 0