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Kelin X. Whipple. Windhorst, Leah M. (Leah Marie), 1981- Massachusetts Institute of Technology. Dept. of Earth, Atmospheric, and Planetary Sciences. Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences n-us-va 2005-09-27T17:20:11Z 2005-09-27T17:20:11Z 2004 2004 http://hdl.handle.net/1721.1/28616 57560495 Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences, 2004. Includes bibliographical references (leaves 28-29). Certain mixed bedrock/alluvial channels located in the Valley and Ridge province of the Appalachians in Virginia were identified as having a pattern of systematic oversteepening of channel gradients at tributary junctions. Where drainage area increased, channel slopes were either increasing or remaining constant. Subsequent investigation of 10m resolution digital elevation models found this pattern to be widespread throughout several large nearby drainage basins (A [approximately] 10⁸m²). Several hypotheses for the causes and constraints of the pattern were tested in two ways: (1) digital profiles were compared to pre-existing data sets for grain-size, channel width, lithology, and drainage area; (2) a short field venture was conducted to test the accuracy of the DEMs and to provide additional data sets such as grain-size and channel width against which to compare the digital longitudinal profiles. Results show that there is some correlation between lithology, drainage area, and a pattern of downstream fining. However, the relationships are not strong and begs an analysis of the region at large to explain this channel gradient phenomenon. Periodically high levels of sediment flux moving through the drainage system, eg. debris flows, are a promising mechanism for the initiation of systematic oversteepening in the longitudinal profiles. by Leah M. Windhorst. S.M. 107 leaves 3696495 bytes 3709038 bytes application/pdf application/pdf en_US Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Earth, Atmospheric, and Planetary Sciences. Systematic oversteepening in longitudinal profiles of mixed bedrock-alluvial channels at tributary junctions : Appalachians, Virginia Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="859148bb-b902-4b75-b3e4-df5fbf7dc557"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>en_US</Language> <Title>Systematic oversteepening in longitudinal profiles of mixed bedrock-alluvial channels at tributary junctions : Appalachians, Virginia</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2004</PublicationDate> <Authors> <Author> <DisplayName>Windhorst, Leah M. (Leah Marie), 1981-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Earth, Atmospheric, and Planetary Sciences.</Keyword> <Abstract>Certain mixed bedrock/alluvial channels located in the Valley and Ridge province of the Appalachians in Virginia were identified as having a pattern of systematic oversteepening of channel gradients at tributary junctions. Where drainage area increased, channel slopes were either increasing or remaining constant. Subsequent investigation of 10m resolution digital elevation models found this pattern to be widespread throughout several large nearby drainage basins (A [approximately] 10⁸m²). Several hypotheses for the causes and constraints of the pattern were tested in two ways: (1) digital profiles were compared to pre-existing data sets for grain-size, channel width, lithology, and drainage area; (2) a short field venture was conducted to test the accuracy of the DEMs and to provide additional data sets such as grain-size and channel width against which to compare the digital longitudinal profiles. Results show that there is some correlation between lithology, drainage area, and a pattern of downstream fining. However, the relationships are not strong and begs an analysis of the region at large to explain this channel gradient phenomenon. Periodically high levels of sediment flux moving through the drainage system, eg. debris flows, are a promising mechanism for the initiation of systematic oversteepening in the longitudinal profiles.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>