气候变化领域集成服务门户(CCPortal): How canyons evolve by incision into bedrock: Rainbow Canyon; Death Valley National Park; United States

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DOI	10.1073/pnas.1911040117
	How canyons evolve by incision into bedrock: Rainbow Canyon; Death Valley National Park; United States
	Zhang L.; Li T.; Wang G.; Kwang J.S.; Nittrouer J.A.; Fu X.; Parker G.
发表日期	2020
ISSN	0027-8424
起始页码	14730
结束页码	14737
卷号	117 期号:26
英文摘要	Incising rivers may be confined by low-slope, erodible hillslopes or steep, resistant sidewalls. In the latter case, the system forms a canyon. We present a morphodynamic model that includes the essential elements of a canyon incising into a plateau, including 1) abrasion-driven channel incision, 2) migration of a canyon-head knickpoint, 3) sediment feed from an alluvial channel upstream of the knickpoint, and 4) production of sediment by sidewall collapse. We calculate incision in terms of collision of clasts with the bed. We calculate knickpoint migration using a moving-boundary formulation that allows a slope discontinuity where the channel head meets an alluvial plateau feeder channel. Rather than modeling sidewall collapse events, we model long-term behavior using a constant sidewall slope as the channel incises. Our morphodynamic model specifically applies to canyon, rather than river–hillslope evolution. We implement it for Rainbow Canyon, CA. Salient results are as follows: 1) Sediment supply from collapsing canyon sidewalls can be substantially larger than that supplied from the feeder channel on the plateau. 2) For any given quasi-equilibrium canyon bedrock slope, two conjugate slopes are possible for the alluvial channel upstream, with the lower of the two corresponding to a substantially lower knickpoint migration rate and higher preservation potential. 3) Knickpoint migration occurs at a substantially faster time scale than regrading of the bedrock channel itself, underlying the significance of disequilibrium processes. Although implemented for constant climactic conditions, the model warrants extension to long-term climate variation. © 2020 National Academy of Sciences. All rights reserved.
英文关键词	Canyonc bedrock; Incision; Knickpoint; Uplift
语种	英语
scopus关键词	Article; environmental parameters; model; priority journal; river; rock; sediment; steady state; United States; water flow
来源期刊	Proceedings of the National Academy of Sciences of the United States of America
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/160897
作者单位	Zhang, L., Department of Civil and Environmental Engineering, University of Illinois Urbana–Champaign, Urbana, IL 61801, United States, State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, 100086, China, School of Water Resources and Electric Power, Qinghai University, Xining, 810016, China; Li, T., State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, 100086, China, School of Water Resources and Electric Power, Qinghai University, Xining, 810016, China; Wang, G., State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing, 100086, China, School of Water Resources and Electric Power, Qinghai University, Xining, 810016, China; Kwang, J.S., Department of Civil and Environmental Engineering, University of Illinois Urbana–Champaign, Urbana, IL 61801, United States, Department of Geosciences, University of Massachusetts, Amherst, MA 01003, United States; Nittrouer, J.A., Department of Earth, Environmental and Planetary Scien...
推荐引用方式 GB/T 7714	Zhang L.,Li T.,Wang G.,et al. How canyons evolve by incision into bedrock: Rainbow Canyon; Death Valley National Park; United States[J],2020,117(26).
APA	Zhang L..,Li T..,Wang G..,Kwang J.S..,Nittrouer J.A..,...&Parker G..(2020).How canyons evolve by incision into bedrock: Rainbow Canyon; Death Valley National Park; United States.Proceedings of the National Academy of Sciences of the United States of America,117(26).
MLA	Zhang L.,et al."How canyons evolve by incision into bedrock: Rainbow Canyon; Death Valley National Park; United States".Proceedings of the National Academy of Sciences of the United States of America 117.26(2020).