LATE QUATERNARY CRUSTAL UPLIFT AND SOUTHWARD SHIFT OF THE LHASA RIVER IN THE LHASA AREA, TIBET
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摘要:
根据数字高程模型、遥感资料分析及实地调查, 拉萨地区在近南北向挤压的作用下, 与NWW向的主构造格架断裂走向相一致, 近东西向的分水岭和沟谷沿南北方向相间分布。自分水岭附近的山顶剥蚀面至盆地, 坡度由平缓、较陡、平缓逐渐过渡, 反映了山顶剥蚀区、强剥蚀区、堆积区的依次变化, 表现了一个完整的构造、气候控制的地貌剥蚀、堆积过程。在同样的气候条件下, 拉萨地区晚第四纪以来的新构造运动整体表现为自北向南的掀斜, 造成北侧剥蚀较强, 下游河流得以携带更多的泥沙物质, 北侧冲、洪积扇汇入拉萨河的物质较南侧多, 加之地壳自北向南的掀斜, 使得拉萨河拉萨段向南迁移, 堆龙曲河口冲积扇也向南迁移。
Abstract:On the basis of the field investigation, digital elevation modeling and remote sense data analysis, the authors think that the nearly E-W-trending watersheds and valleys in the Lhasa area are distributed alternately from north to south under the nearly N-S compression, parallelly to the WNWtrending main faults.From the erosional surfaces of the summits near the watersheds to catchment basins, the hill slope changes from being gentle to being relatively steep and again to being gentle, indicating a successive change from the hilltop erosion zone through intense erosion zone to sedimentation zone and a complete process of erosion and sedimentation under the tectonic-climatic control.Under the same climatic conditions, the Lhasa block tilted to the south during the late Quaternary neotectonic movement, and as a result, the northern Lhasa block has been eroded more intensely than the southern block, and therefore the downstream reaches carry more sand and mud.As more alluvial-diluvial fan deposits from the northern block flow to the Lhasa River than those from the southern block and in addition the crust tilts from north to south, the Lhasa reach of the Lhasa River has shifted toward the south and so has the alluvial fan of the Doilung Qu river mouth.
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Key words:
- erosion /
- crustal uplift /
- alluvial-diluvial fan /
- digital elevation model /
- Qinghai-Tibet Plateau
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[1] Molnar P, England P, Martinod J.Mantle dynamics, uplift of the Tibetan Plateau and the Indian monsoon[J].Reviews of Geophysics, 1993, 31 (4):357～ 396. doi: 10.1029/93RG02030
[2] Fielding EJ.Tibet uplift and erosion[J].Tectonophysics, 1996, 260 (1996):55～ 84. http://d.old.wanfangdata.com.cn/Periodical/dzxb-e200004010
[3] Whipple KX, Hancock GS, Anderson RS.River incision into bedrock:Mechanics and relative efficacy of plucking, abrasion and cavitation[J].Geological Society of America Bulletin, 2000, 112 (3):490～ 503. doi: 10.1130/0016-7606(2000)112<490:RIIBMA>2.0.CO;2
[4] Bonnet S, Crave A.Landscape response to climate change:Insights from experimental modeling and implications for tectonic versus climatic uplift of topography[J].Geology, 2003, 31 (2):123～ 126. doi: 10.1130/0091-7613(2003)031<0123:LRTCCI>2.0.CO;2
[5] 吴中海, 赵希涛, 吴珍汉, 等.西藏当雄—羊八井盆地的第四纪地质与断裂活动研究[J].地质力学学报, 2006, 12(3):305～ 316. doi: 10.3969/j.issn.1006-6616.2006.03.004 http://journal.geomech.ac.cn/ch/reader/view_abstract.aspx?flag=1&file_no=20060343&journal_id=dzlxxb
[6] 朱大岗, 赵希涛, 孟宪刚, 等.从冰川剥蚀作用看念青唐古拉山脉(中段)的隆升[J].地球学报, 2005, 26 (2):137～ 144. doi: 10.3321/j.issn:1006-3021.2005.02.006
[7] 赵希涛, 吴中海, 朱大岗, 等.念青唐古拉山脉西段第四纪冰川作用[J].第四纪研究, 2002, 22 (5):424 ～ 433. doi: 10.3321/j.issn:1001-7410.2002.05.004
[8] 程三友, 刘少峰, 张会平, 等.大别山构造地貌的DEM初步分析[J].地质力学学报, 2005, 11 (4):333～ 340. doi: 10.3969/j.issn.1006-6616.2005.04.006 http://journal.geomech.ac.cn/ch/reader/view_abstract.aspx?flag=1&file_no=20050447&journal_id=dzlxxb
[9] Carretier S, Lucazeau F.How does alluvial sedimentation at range fronts modify the erosional dynamics of mountain catchments[J].Basin Research, 2005, 17 (3):361～ 381. doi: 10.1111/bre.2005.17.issue-3
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