DOI: 10.1016/j.epsl.2017.11.047
Scopus记录号: 2-s2.0-85040794165
论文题名: Coupling erosion and topographic development in the rainiest place on Earth: Reconstructing the Shillong Plateau uplift history with in-situ cosmogenic 10Be
作者: Rosenkranz R. ; Schildgen T. ; Wittmann H. ; Spiegel C.
刊名: Earth and Planetary Science Letters
ISSN: 0012821X
出版年: 2018
卷: 483 起始页码: 39
结束页码: 51
语种: 英语
英文关键词: 10Be
; erosion
; land-use change
; orographic rainfall
; river profile analysis
Scopus关键词: Catchments
; Earthquakes
; Land use
; Landforms
; Rain
; Rivers
; Runoff
; Stratigraphy
; Tectonics
; Land-use change
; Orographic rainfalls
; Precipitation patterns
; River profile
; Strain partitioning
; Terrestrial cosmogenic nuclides
; Topographic analysis
; ^10Be
; Erosion
; beryllium isotope
; cosmogenic radionuclide
; erosion rate
; exhumation
; land use change
; orographic effect
; rainfall
; reconstruction
; river system
; topography
; Bengal
; Brahmaputra River
; Himalayas
; India
; Shillong Plateau
英文摘要: The uplift of the Shillong Plateau, in northeast India between the Bengal floodplain and the Himalaya Mountains, has had a significant impact on regional precipitation patterns, strain partitioning, and the path of the Brahmaputra River. Today, the plateau receives the highest measured yearly rainfall in the world and is tectonically active, having hosted one of the strongest intra-plate earthquakes ever recorded. Despite the unique tectonic and climatic setting of this prominent landscape feature, its exhumation and surface uplift history are poorly constrained. We collected 14 detrital river sand and 3 bedrock samples from the southern margin of the Shillong Plateau to measure erosion rates using the terrestrial cosmogenic nuclide 10Be. The calculated bedrock erosion rates range from 2.0 to 5.6 m My−1, whereas catchment average erosion rates from detrital river sands range from 48 to 214 m My−1. These rates are surprisingly low in the context of steep, tectonically active slopes and extreme rainfall. Moreover, the highest among these rates, which occur on the low-relief plateau surface, appear to have been affected by anthropogenic land-use change. To determine the onset of surface uplift, we coupled the catchment averaged erosion rates with topographic analyses of the plateau's southern margin. We interpolated an inclined, pre-incision surface from minimally eroded remnants along the valley interfluves and calculated the eroded volume of the valleys carved beneath the surface. The missing volume was then divided by the volume flux derived from the erosion rates to obtain the onset of uplift. The results of this calculation, ranging from 3.0 to 5.0 Ma for individual valleys, are in agreement with several lines of stratigraphic evidence from the Brahmaputra and Bengal basin that constrain the onset of topographic uplift, specifically the onset of flexural loading and the transgression from deltaic to marine deposition. Ultimately, our data corroborate the hypothesis that surface uplift was decoupled from the onset of rapid exhumation, which occurred several millions of years earlier. © 2017 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/110084
Appears in Collections: 影响、适应和脆弱性 气候变化事实与影响
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作者单位: Geodynamics of the Polar Regions, University of Bremen, Klagenfurter Str., Bremen, 28359, Germany; Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Telegrafenberg, Potsdam, 14473, Germany; Department of Earth and Environmental Sciences, University of Potsdam, Potsdam, 14473, Germany
Recommended Citation:
Rosenkranz R.,Schildgen T.,Wittmann H.,et al. Coupling erosion and topographic development in the rainiest place on Earth: Reconstructing the Shillong Plateau uplift history with in-situ cosmogenic 10Be[J]. Earth and Planetary Science Letters,2018-01-01,483