HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Mattheus, C. R. Articles by Anderson, J. B. Search for Related Content GeoRef GeoRef Citation

Control of Upstream Variables on Incised-Valley Dimension

¹ Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3431 Arendell Street, Morehead City, North Carolina 28557, U.S.A.
² Institute of Marine Sciences, University of North Carolina at Chapel Hill, 3431 Arendell Street, Morehead City, North Carolina 28557, U.S.A.; abrodrig{at}email.unc.edu
³ ConocoPhillips, 600 North Dairy Ashford, Houston, Texas 77079, U.S.A.
⁴ Boone Pickens School of Geology, Oklahoma State University, Stillwater, Oklahoma 74078
⁵ Department of Earth Sciences, Rice University, Box 1982, Houston, Texas 77251-1982, U.S.A.

It is well documented that sea level fell during the Last Glacial Maximum, shifting graded-stream profiles out of equilibrium and causing rivers to incise into continental shelves. Although incised valleys have been heavily researched, the interplay between upstream and downstream controls on incised-valley dimension are not well constrained. To address this lack of understanding, we examined the cross-sectional dimension of nine incised valleys located across the northern Gulf of Mexico margin and bounded by the sequence boundary associated with the last sea-level lowstand. These incised valleys are distinguished by drainage basins that vary in size by three orders of magnitude, cover a margin that presently has a steep climate gradient, and extend across a continental shelf that varies along strike in width and gradient.

Incision depths vary for valleys that have similar gradient profiles but different drainage-basin areas, suggesting significant control of upstream variables on incised-valley morphology. Additionally, these data show a strong linear correlation between drainage-basin area and incised-valley cross-sectional area. This suggests applicability of the empirically derived relationship between modern discharge and cross-sectional channel area to incised valleys when compared at the maximum highstand shoreline of the previous sequence. Incised-valley dimension adjusts over a longer period than the lowstand and is in equilibrium with drainage-basin area, which is considered a proxy for long-term discharge. Although base-level fall promotes incision, upstream variables control incised-valley dimensions.

This article has been cited by other articles:

				S. K. Davidson and C. P. North Geomorphological Regional Curves for Prediction of Drainage Area and Screening Modern Analogues for Rivers in the Rock Record Journal of Sedimentary Research, October 1, 2009; 79(10): 773 - 792. [Abstract] [Full Text] [PDF]