Discovery and Significance of the Lacustrine Sedimentation in the Middle Reach of Yarlung Zangbo River in Tibetan Plateau

Abstract

Abstract:

The authors recognized a barrier lake in the middle reach of the Yarlung Zangbo River, which is formed by the glacier blocking the river during the late stage of Late Pleistocene. The field investigation finds that the lacustrine strata are in the Sangri County, Nêdong County, Zhanang County and other places along the middle reach of Yarlung Zangbo River, showing that the lake is a large paleaolake with an area of more than 700 km² from Zaba village near Sangri County (east) to Gonggar airport (west), i.e.the Jiedexiu paleaolake. The lacustrine sedimentary section is typically a continuous silty clay layer and has horizontal bedding structures; the thickness of the section in Jiedexiu town of Gonggar County is the largest and more than 10 meters; the AMS ¹⁴C age of the top of the section is 15,680-15,105 aBP, belonging to the Last Glacial Maximum (LGM) period. Combined with the formation age and sedimentary characteristics of the lacustrine strata in Linzhi, Songzong, Gega paleaolake and other areas along the lower reach of the Yarlung Zangbo River, the results reveal that the Jiedexiu paleaolake develops during the LGM period; the characteristics of sediments and storage capacity of paleaolake show that the Jiedexiu paleaolake is not completely blocked during developing period, but a large-scale lake of taking in and sending out waters, liking a modern reservoir. The spatial characteristics of moraine, which is found in the south bank of the Yarlung Zangbo River, and lacustrine sediments in the board valley of the river, indicate that the Jiedexiu paleaolake is formed from glaciers blocking the Yarlung Zangbo River during the LGM period. This paper also demonstrates that the Yarlung Zangbo River is an antecedent river, it isn’t formed by headwater erosion of many paleaolake in the region, but it exists there before the formation of the Jiedexiu and other paleaolakes. Paleaolakes, such as Jiedexiu paleaolake in the Yarlung Zangbo River basin, are formed by blocking river valley caused by climate changes, neotectonic movement, and seismic activity and so on.

Key words: glacial lake, ¹⁴C dating, Last Glacial Maximum(LGM), Yarlung Zangbo River, lacustrine sedimentation

CLC Number:

P642.2

HAN Jian’en, MENG Qingwei, GUO Changbao, SHAO Zhaogang, WANG Jin, YU Jia, XU Biao. Discovery and Significance of the Lacustrine Sedimentation in the Middle Reach of Yarlung Zangbo River in Tibetan Plateau[J]. Geoscience, 2017, 31(05): 890-899.

Figures/Tables 10

Fig.1 ETM image and major faults along Yarlung Zangbo River in the broad valley of Shannan region in Tibet

Fig.2 Distribution and characteristics of the typical lacustrine strata in the board valley of Shannan in the middle reach of Yarlung Zangbo River

Fig.3 Characteristics of the typical lacustrine strata in western Jiedexiu town

Fig.4 Lacustrine stratum section in Jiedexiu town (section of Fig.3(a))

Fig. 5 Lacustrine stratum section in Jiedexiu town (section of Fig.3(b))

Table 1 AMS 14C dating result of shell in lacustrine strata

样号	实验室编号	测年材料	¹⁴C年龄 /aBP	日历校正年龄 /aBP
XZ069-4	Beta-417778	螺壳	12 860±100	15 680~15 105

Fig.6 Profile of valleys at some locations along Shannan section of the Yarlung Zangbo River

Table 2 Formation age of lacustrine strata in drainage basins along Yarlung Zangbo River

古湖名称	堰塞河流	测试方法	时代/kaBP	资料来源
松宗古湖	帕隆藏布	光释光	16.1±1.7(剖面顶) 22.5±3.3(剖面底)	曾庆利等^[11]
林芝古湖(T₃湖相地层)	雅鲁藏布江	¹⁴C	11 190~11 300	刘宇平等^[10]
格嘎古湖	雅鲁藏布江	光释光	75~40	Zhu等^[24]
格嘎古湖	雅鲁藏布江	光释光	1.8~1.2	祝嵩等^[15]
林芝古湖(L6)	雅鲁藏布江	¹⁴C	8.86±0.04	Montgomery等^[7]
林芝古湖(L2)	雅鲁藏布江	¹⁴C	9.87±0.05	Montgomery等^[7]

Fig.7 Drift dam of the middle reach of Yarlung Zangbo River in Zhaba of Sangri County, Tibet

Fig.8 Distribution of the Jiedexiu paleaolake

References 38

[1]	HANSON M A, LIAN O B, CIAGUE J J. The sequence and timing of large Late Pleistocene floods from glacial Lake Missoula[J]. Quaternary Science Reviews, 2012, 31(1): 67-81. DOI URL
[2]	WAITT R B. Case for periodic, colossal jökulhlaups from Pleistocene glacial Lake Missoula[J]. Geological Society of America Bulletin, 1985, 96(10):1271-1286. DOI URL
[3]	JIANG H C, MAO X, XU H Y, et al. Provenance and earthquake signature of the last deglacial Xinmocun lacustrine sediments at Diexi, East Tibet[J]. Geomorphology, 2014, 204(1):518-531. DOI URL
[4]	WANG P, ZHANG B, QIU W L, et al. Soft-sediment deformation structures from the Diexi paleo-dammed lakes in the upper reaches of the Minjiang River, east Tibet[J]. Journal of Asian Earth Sciences, 2011, 40(4):865-872. DOI URL
[5]	ZHANG Y S, ZHAO X T, LAN H X, et al. A Pleistocene landslide-dammed lake, Jinsha River, Yunnan, China[J]. Quaternary International, 2011, 233(1):72-80. DOI URL
[6]	RICHARDSON S D, REYNOLDS J M. An overview of glacial hazards in the Himalayas[J]. Quaternary International, 2000, 65/66: 31-47. DOI URL
[7]	MONTGOMERY D R, HALLET B, LIU Y P, et al. Evidence for Holocene megafloods down the Tsangpo River Gorge, Southeastern Tibet[J]. Quaternary Research, 2004, 62(2): 201-207. DOI URL
[8]	施雅风, 郑本兴, 苏珍. 第四纪冰川、冰期间冰期旋回与环境变化[M]//施雅风.中国冰川与环境. 北京: 科学出版社, 2000: 336-347.
[9]	陈智梁, 孙志明, ROYDEN L H, 等. 四川泸定昔格达组的堰塞湖成因及其意义[J]. 第四纪研究, 2004, 24(6): 614-620.
[10]	刘宇平, MONTGOMERY D R, HALLET B, 等. 西藏东南雅鲁藏布大峡谷入口处第四纪多次冰川阻江事件[J]. 第四纪研究, 2006, 26(1): 52-62.
[11]	曾庆利, 杨志法, 袁广祥, 等. 松宗古湖——藏东南帕隆藏布江末次盛冰期发育的一个冰川堰塞湖[J]. 第四纪研究, 2007, 27(1): 85-92.
[12]	张永双, 赵希涛. 澜沧江云南德钦古水一带第四纪堰塞湖的沉积特征及其环境意义[J]. 地质学报, 2008, 82(2): 262-268.
[13]	张永双, 赵希涛, 胡道功. 滇西北德钦地区金沙江奔子栏古堰塞湖的发现及意义[J]. 地质通报, 2007, 26(8): 970-975.
[14]	姚檀栋, 李治国, 杨威, 等. 雅鲁藏布江流域冰川分布和物质平衡特征及其对湖泊的影响[J]. 科学通报, 2010, 55(18): 1750-1756.
[15]	祝嵩, 吴珍汉, 赵希涛, 等. 用OSL方法确定雅鲁藏布江大拐弯第四纪晚期冰川堰塞湖年龄[J]. 地球学报, 2013, 34(2):246-250.
[16]	韩同林. 西藏活动构造[M]. 北京: 地质出版社, 1987:1-50.
[17]	杨逸畴. 南迦巴瓦峰地区地貌的基本特征和成因[J]. 山地研究, 1984, 2(3): 134-143.
[18]	张文敬, 高登义. 世界第一大峡谷——雅鲁藏布大峡谷科学考察新进展[J]. 山地学报, 1999, 17(2): 99-103.
[19]	张文敬. 南迦巴瓦峰跃动冰川的某些特征[J]. 山地研究, 1985, 3(4): 234-238.
[20]	李翠平, 王萍, 钱达, 等. 雅鲁藏布江大峡谷入口河段最近两期古堰塞湖事件的年龄[J]. 地震地质, 2015, 37(4):1136-1146.
[21]	张沛全, 刘小汉, 孔屏, 等. 雅鲁藏布江大拐弯地区末次冰期以来的冰川活动证据及其构造-环境意义[J]. 地质科学, 2008, 43(3):588-602.
[22]	OWEN L A, DORTCH J M. Nature and timing of Quaternary glaciation in the Himalayan-Tibetan orogen[J]. Quaternary Science Reviews, 2014, 88: 14-54. DOI URL
[23]	OWEN L A, FINKEL R C, BARNARD P L, et al. Climatic and topographic controls on the style and timing of Late Quaternary glaciation throughout Tibet and the Himalaya defined by ¹⁰Be cosmogenic radionuclide surface exposure dating[J]. Quaternary Science Reviews, 2005, 24(12): 1391-1411. DOI URL
[24]	ZHU S, WU Z H, ZHAO X T, et al. Middle-Late Pleistocene glacial lakes in the grand canyon of the Tsangpo River, Tibet[J]. Acta Geologica Sinica, 2012, 86(1): 266-283. DOI URL
[25]	黄艳, 袁鹏, 颜志衡. 雅鲁藏布江流域天然径流特征及规律分析[J]. 红水河, 2010, 29(1): 65-69.
[26]	邵兆刚, 孟宪刚, 朱大岗, 等. 青藏高原层状地貌特征及其成因初探[J]. 地学前缘, 2009, 16(6): 186-194.
[27]	韩建恩, 余佳, 邵兆刚, 等. 黄河源晚新生代河湖相沉积与环境[M]. 北京: 地质出版社, 2013:1-5.
[28]	陈建军, 季建清, 龚俊峰, 等. 雅鲁藏布江大峡谷的形成[J]. 地质通报, 2008, 27(4): 491-499.
[29]	HUANG S Y, LIN Y N, CHEN Y G, et al. The implication of elevated lacustrine sediments in the middle reach of the Yarlung-Tsangpo and Nyang River, Tibet[M]// The Cultural History of the Arabs. London: Aurum Press, 2007:5415-5418.
[30]	王富葆, 张厚生. 南迦巴瓦峰地区第四纪地质拾零[J]. 山地研究, 1985, 3(4):321-324.
[31]	CINA S E, YIN A, GROVE M, et al. Gangdese arc detritus within the eastern Himalayan Neogene foreland basin: Implications for the Neocene evolution of the Yalu-Brahmaputra River system[J]. Earth and Planetary Science Letters, 2009, 285(1/2):150-162. DOI URL
[32]	ZHANG J Y, YIN A, LIU W C, et al. Coupled U-Pb dating and Hf isotopic analysis of detrital zircon of modern river sand from the Yalu River (Yarlung Tsangpo) drainage system in southern Tibet: Constraints on the transport processes and evolution of Himalayan rivers[J]. Geological Society of America Bulletin, 2012, 124(9/10): 1449-1473. DOI URL
[33]	WANG P, SCHERLER D, LIU-ZENG J, et al. Tectonic control of Yarlung Tsangpo Gorge revealed by a buried canyon in Southern Tibet[J]. Science, 2014, 346: 978-981. DOI PMID
[34]	KORUP O, MONTGOMERY D R. Tibetan plateau river incision inhibited by glacial stabilization of the Tsangpo gorge[J]. Nature, 2008, 455: 786-789. DOI
[35]	KORUP O, MONTGOMERY D R, HEWITT K. Glacier and landslide feedbacks to topographic relief in the Himalayan syntaxes[J]. Proceedings of the National Academy of Sciences of the United States of America, 2010, 17(12): 5317-5322.
[36]	BROOKFIELD M E. Evolution of the great river systems of southern Asia during the Cenozoic India-Asia collision: Rivers draining north from the Pamir syntaxis[J]. Geomorphology, 2008, 100(3/4):296-311. DOI URL
[37]	王二七, 陈良忠, 陈智樑. 在构造和气候因素制约下的雅鲁藏布江的演化[J]. 第四纪研究, 2002, 22(4):365-373.
[38]	季建清, 钟大赉, 丁林, 等. 雅鲁藏布大峡谷地质成因[J]. 地学前缘, 1999, 6(4): 231-235.