气候变化领域集成服务门户(CCPortal): Preserved Fluvial Cross Strata Record Bedform Disequilibrium Dynamics

CCPortal

DOI	10.1029/2019GL085910
	Preserved Fluvial Cross Strata Record Bedform Disequilibrium Dynamics
	Leary K.C.P.; Ganti V.
发表日期	2020
ISSN	0094-8276
卷号	47 期号:2
英文摘要	Fluvial cross strata are an archive of ancient river morphodynamics. Controls on their preservation are well documented for bedforms equilibrated with prevailing flows; however, variability in water and sediment discharge results in bedforms that are routinely out of phase with flow conditions—termed bedform disequilibrium. Using theory and experiments of dune evolution in steady and unsteady flows, we show that preservation of cross strata is greater during unsteady flows—particularly during flood recession—when bedform disequilibrium is prevalent. The enhanced preservation of disequilibrium dynamics is associated with a high bedform preservation ratio, which results from localized increase in sedimentation rates relative to bedform migration rates due to the hierarchical bedform organization during flood recession. We find that the coefficient of variation of cross sets reflects the ratio of the time scales of formative-flood variability and bedform adjustment. We parameterize bedform disequilibrium for rivers globally and suggest that flood variability is a key control on cross set preservation. ©2019. American Geophysical Union. All Rights Reserved.
英文关键词	Unsteady flow; Bed forms; Coefficient of variation; deep time; Flow condition; Migration rates; River morphodynamics; Sediment discharge; Sedimentation rates; Floods; bedform; discharge; disequilibrium; dune formation; flood frequency; hierarchical system; hysteresis; morphodynamics; parameterization; sandstone; sedimentation; steady flow; unsteady flow
语种	英语
来源期刊	Geophysical Research Letters
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/170823
作者单位	Department of Geography, University of California, Santa Barbara, CA, United States; Department of Earth Science, University of California, Santa Barbara, CA, United States
推荐引用方式 GB/T 7714	Leary K.C.P.,Ganti V.. Preserved Fluvial Cross Strata Record Bedform Disequilibrium Dynamics[J],2020,47(2).
APA	Leary K.C.P.,&Ganti V..(2020).Preserved Fluvial Cross Strata Record Bedform Disequilibrium Dynamics.Geophysical Research Letters,47(2).
MLA	Leary K.C.P.,et al."Preserved Fluvial Cross Strata Record Bedform Disequilibrium Dynamics".Geophysical Research Letters 47.2(2020).