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	Mega-meander paleochannels of the southeastern Atlantic Coastal Plain, USA
	Suther, Bradley E.1; Leigh, David S.2; Brook, George A.2; Yang, LinHai3
刊名	PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
	2018-12-15
卷号	511页码:52-79
关键词	Bankfull flow Carolina Climate change Discharge Georgia Late Pleistocene
ISSN号	0031-0182
DOI	10.1016/j.palaeo.2018.07.002
通讯作者	Suther, Bradley E.(bsuther@kennesaw.edu)
英文摘要	Paleodischarge estimates based on the slope-area method and channel boundaries determined from stratigraphic cross-sections indicate that large, terminal Pleistocene meandering paleochannels ("mega-meanders") in river valleys of the southeastern Atlantic Coastal Plain of the United States represent bankfull flows that were at least double the magnitude of those on modern rivers. Correlation of radiocarbon-and luminescence-dated paleomeanders with previously reported pollen and eolian sedimentary records suggests that greater discharge was driven by seasonally wetter conditions resulting from dynamic changes to regional precipitation and runoff that occurred in association with global warming at the end of the Pleistocene. While reflecting larger channel forming flows, the exceptionally large widths and radii of curvature of mega-meanders were nonetheless maintained by a relatively modest discharge magnitude that was between two and four times larger than modern bankfull flow and within the size range of the present two-to five-year flood. Despite their large planform, the paleochannels conveyed relatively modest bankfull discharges because a wide, shallow shape limited their cross-sectional area and hydraulic radius. Within the late Quaternary evolution of fluvial systems in the region, scrolled mega-meanders constitute a transitional meandering planform that remained influenced by large volumes of sandy bedload following the sand-bed braided channels of the late Wisconsin interval, circa 30-17 ka. In addition to greater discharge, the large planimetric dimensions of paleochannels reflect a lack of cohesive vertical accretion facies on paleomeander floodplains, a sediment regime that transported large quantities of bedload sand, and the influence of these factors on channel boundary composition, bank stability, and channel shape. Findings underscore the importance of reconstructing channel cross-sectional dimensions and slope when estimating discharge for infilled paleomeanders. This approach reduces uncertainties surrounding channel crosssectional area, gradient, and boundary composition inherent to studies lacking subsurface data that rely upon meander geometry to retrodict discharge.
收录类别	SCI
WOS关键词	CLIMATE-CHANGE ; FLUVIAL RESPONSE ; LATE PLEISTOCENE ; SEA-LEVEL ; ENVIRONMENTAL-CHANGE ; CONTINENTAL-SHELF ; NORTH-CAROLINA ; UNITED-STATES ; RIVER ; LUMINESCENCE
WOS研究方向	Physical Geography ; Geology ; Paleontology
WOS类目	Geography, Physical ; Geosciences, Multidisciplinary ; Paleontology
语种	英语
出版者	ELSEVIER SCIENCE BV
WOS记录号	WOS:000452583600004
内容类型	期刊论文
URI标识	http://www.corc.org.cn/handle/1471x/2558240
专题	寒区旱区环境与工程研究所
通讯作者	Suther, Bradley E.
作者单位	1.Kennesaw State Univ, Dept Geog & Anthropol, Kennesaw, GA 30144 USA 2.Univ Georgia, Dept Geog, Athens, GA 30602 USA 3.Chinese Acad Sci, Northwest Inst Ecoenvironm & Resources, Key Lab Desert & Desertificat, Lanzhou 730000, Gansu, Peoples R China
推荐引用方式 GB/T 7714	Suther, Bradley E.,Leigh, David S.,Brook, George A.,et al. Mega-meander paleochannels of the southeastern Atlantic Coastal Plain, USA[J]. PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,2018,511:52-79.
APA	Suther, Bradley E.,Leigh, David S.,Brook, George A.,&Yang, LinHai.(2018).Mega-meander paleochannels of the southeastern Atlantic Coastal Plain, USA.PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY,511,52-79.
MLA	Suther, Bradley E.,et al."Mega-meander paleochannels of the southeastern Atlantic Coastal Plain, USA".PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY 511(2018):52-79.

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