气候变化领域集成服务门户(CCPortal): Erosion during extreme flood events dominates holocene canyon evolution in northeast iceland

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DOI	10.1073/pnas.1415443112
	Erosion during extreme flood events dominates holocene canyon evolution in northeast iceland
	Baynes E.R.C.; Attal M.; Niedermann S.; Kirstein L.A.; Dugmore A.J.; Naylor M.
发表日期	2015
ISSN	0027-8424
起始页码	2355
结束页码	2360
卷号	112 期号:8
英文摘要	Extreme flood events have the potential to cause catastrophic landscape change in short periods of time (10 0 to 10 3 h). However, their impacts are rarely considered in studies of long-term landscape evolution ( >103 y), because the mechanisms of erosion during such floods are poorly constrained. Here we use topographic analysis and cosmogenic 3 He surface exposure dating of fluvially sculpted surfaces to determine the impact of extreme flood events within the Jökulsárgljúfur canyon (northeast Iceland) and to constrain the mechanisms of bedrock erosion during these events. Surface exposure ages allow identification of three periods of intense canyon cutting about 9 ka ago, 5 ka ago, and2 ka ago during which multiple large knickpoints retreated large distances ( >2 km). During these events, a threshold flow depth was exceeded, leading to the toppling and transportation of basalt lava columns. Despite continuing and comparatively largescale (500 m 3 / s) discharge of sediment-rich glacial meltwater, there is no evidence for a transition to an abrasion-dominated erosion regime since the last erosive event because the vertical knickpoints have not diffused over time. We provide a model for the evolution of the Jökulsárgljúfur canyon through the reconstruction of the river profile and canyon morphology at different stages over the last 9 ka and highlight the dominant role played by extreme flood events in the shaping of this landscape during the Holocene.
英文关键词	Bedrock erosion; Cosmogenic 3he; Extreme floods; Iceland; Knickpoints
语种	英语
scopus关键词	Article; chronology; erosion; evolution; flooding; Holocene; Iceland; landscape; morphology; priority journal; river; sediment; topography
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/159097
作者单位	Baynes, E.R.C., School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, United Kingdom; Attal, M., School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, United Kingdom; Niedermann, S., Deutsches GeoForschungsZentrum, Potsdam, D-14473, Germany; Kirstein, L.A., School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, United Kingdom; Dugmore, A.J., School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, United Kingdom; Naylor, M., School of GeoSciences, University of Edinburgh, Edinburgh, EH8 9XP, United Kingdom
推荐引用方式 GB/T 7714	Baynes E.R.C.,Attal M.,Niedermann S.,et al. Erosion during extreme flood events dominates holocene canyon evolution in northeast iceland[J],2015,112(8).
APA	Baynes E.R.C.,Attal M.,Niedermann S.,Kirstein L.A.,Dugmore A.J.,&Naylor M..(2015).Erosion during extreme flood events dominates holocene canyon evolution in northeast iceland.Proceedings of the National Academy of Sciences of the United States of America,112(8).
MLA	Baynes E.R.C.,et al."Erosion during extreme flood events dominates holocene canyon evolution in northeast iceland".Proceedings of the National Academy of Sciences of the United States of America 112.8(2015).