Skip to Main Content
Skip Nav Destination
GEOREF RECORD

Elevation gaps in fluvial sandbar deposition and their implications for paleodepth estimation

Jason S. Alexander, Brandon J. McElroy, Snehalata Huzurbazar and Marissa L. Murr
Elevation gaps in fluvial sandbar deposition and their implications for paleodepth estimation
Geology (Boulder) (April 2020) 48 (7): 718-722

Abstract

Accurate estimation of paleo-streamflow depth from outcrop is important for estimation of channel slopes, water discharges, sediment fluxes, and basin sizes of ancient river systems. Bar-scale inclined strata deposited from slipface avalanching on fluvial bar margins are assumed to be indicators of paleodepth insofar as their thickness approaches but does not exceed formative flow depths. We employed a unique, large data set from a prolonged bank-filling flood in the sandy, braided Missouri River (USA) to examine scaling between slipface height and measures of river depth during the flood. The analyses demonstrated that the most frequent slipface height observations underestimate study-reach mean flow depth at peak stage by a factor of 3, but maximum values are approximately equal to mean flow depth. At least 70% of the error is accounted for by the difference between slipface base elevation and mean bed elevation, while the difference between crest elevation and water surface accounts for approximately 30%. Our analysis provides a scaling for bar-scale inclined strata formed by avalanching and suggests risk of systematic bias in paleodepth estimation if mean thickness measurements of these deposits are equated to mean bankfull depth.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 48
Serial Issue: 7
Title: Elevation gaps in fluvial sandbar deposition and their implications for paleodepth estimation
Affiliation: University of Wyoming, Department of Geology and Geophysics, Laramie, WY, United States
Pages: 718-722
Published: 20200429
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 24
Accession Number: 2021-011277
Categories: Sedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. sketch map
N43°00'00" - N43°00'00", W97°00'00" - W97°00'00"
Secondary Affiliation: West Virginia University, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2021, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 202108
Close Modal

or Create an Account

Close Modal
Close Modal