DOI: 10.1016/j.earscirev.2021.103717
论文题名: The role of infrequently mobile boulders in modulating landscape evolution and geomorphic hazards
作者: Shobe C.M. ; Turowski J.M. ; Nativ R. ; Glade R.C. ; Bennett G.L. ; Dini B.
刊名: Earth Science Reviews
ISSN: 00128252
出版年: 2021
卷: 220 语种: 英语
中文关键词: Boulders
; Channel-hillslope coupling
; Geohazards
; Geomorphology
; Hillslopes
; Landscape evolution
; Rivers
英文关键词: boulder
; exhumation
; fluvial geomorphology
; grain size
; hillslope
; landscape evolution
; landslide
; river channel
; rockfall
; sediment transport
; size distribution
英文摘要: A landscape's sediment grain size distribution is the product of, and an important influence on, earth surface processes and landscape evolution. Grains can be large enough that the motion of a single grain, infrequently mobile in size-selective transport systems, constitutes or triggers significant geomorphic change. We define these grains as boulders. Boulders affect landscape evolution; their dynamics and effects on landscape form have been the focus of substantial recent community effort. We review progress on five key questions related to how boulders influence the evolution of unglaciated, eroding landscapes: 1) What factors control boulder production on eroding hillslopes and the subsequent downslope evolution of the boulder size distribution? 2) How do boulders influence hillslope processes and long-term hillslope evolution? 3) How do boulders influence fluvial processes and river channel shape? 4) How do boulder-mantled channels and hillslopes interact to set the long-term form and evolution of boulder-influenced landscapes? 5) How do boulders contribute to geomorphic hazards, and how might improved understanding of boulder dynamics be used for geohazard mitigation? Boulders are produced on eroding hillslopes by landsliding, rockfall, and/or exhumation through the critical zone. On hillslopes dominated by local sediment transport, boulders affect hillslope soil production and transport processes such that the downslope boulder size distribution sets the form of steady-state hillslopes. Hillslopes dominated by nonlocal sediment transport are less likely to exhibit boulder controls on hillslope morphology as boulders are rapidly transported to the hillslope toe. Downslope transport delivers boulders to eroding rivers where the boulders act as large roughness elements that change flow hydraulics and the efficiency of erosion and sediment transport. Over longer timescales, river channels adjust their geometry to accommodate the boulders supplied from adjacent hillslopes such that rivers can erode at the baselevel fall rate given their boulder size distribution. The delivery of boulders from hillslopes to channels, paired with the channel response to boulder delivery, drives channel-hillslope feedbacks that affect the transient evolution and steady-state form of boulder-influenced landscapes. At the event scale, boulder dynamics in eroding landscapes represent a component of geomorphic hazards that can be mitigated with an improved understanding of the rates and processes associated with boulder production and mobility. Opportunities for future work primarily entail field-focused data collection across gradients in landscape boundary conditions (tectonics, climate, and lithology) with the goal of understanding boulder dynamics as one component of landscape self-organization. © 2021 The Author(s) Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/166504
Appears in Collections: 气候变化与战略
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作者单位: Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences, Potsdam, Germany; Department of Geology and Geography, West Virginia University, Morgantown, WV, United States; Institute of Earth and Environmental Science, University of Potsdam, Potsdam, Germany; Department of Earth and Environmental Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel; Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY, United States; Geography, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom; School of Environmental Sciences, University of East Anglia, Norwich, United Kingdom
Recommended Citation:
Shobe C.M.,Turowski J.M.,Nativ R.,et al. The role of infrequently mobile boulders in modulating landscape evolution and geomorphic hazards[J]. Earth Science Reviews,2021-01-01,220