Asymmetry in the planform morphology of alluvial fans : a geomorphological analysis

• Main Author: Whitehouse, Bryce Matthew
• Other Authors: Giles, Philip, 1967-
• Format: Text
• Language: English
• Published: Halifax, N.S. : Saint Mary's University 2013
• Subjects: Canada; Yukon; Alaska
• Online Access: http://library2.smu.ca/xmlui/handle/01/24954

1 online resource (xi, 83 p.) : ill., maps Includes abstract and appendix. Includes bibliographical references (p. 69-73). Since alluvial fans became a topic of modern research in the 1960’s, there has been a lack of research publications on fan asymmetry in planfom. The aim of this study is to provide some insight into the planform morphology of fans being modified by axial rivers. Fans chosen for this study had to be in areas with adequate accommodation space, and could not be encroached upon by other fans nor have conjoining valleys near the apex. The broad glaciated valleys of Yukon, Canada, and Alaska, U.S.A, contain a sufficient number of suitable fans to build a dataset for planform asymmetry analysis. To collect these data, individual fans were outlined in Google Earth and divided geometrically into five equal “pie” parts. Profiles along outer parts of the fan were then measured in length from apex to toe, with the ratio of longer to shorter profile representing the degree of fan asymmetry. Results show that fans modified by axial rivers do predominantly have longer profiles on the downstream side of the axial valley, meaning that the planform morphology is asymmetrical. In addition to planform asymmetry, this study will investigate whether there is a significant difference in longitudinal profile gradients between the upstream and downstream side on asymmetrical fans, and whether the distribution of fan surface streams is affected by fan asymmetry. RÉSUMÉ Depuis que les éventails alluvionnaires sont devenus un sujet moderne de recherche dans les années 1960s, il y a un manque de recherche publié concernant l’asymétrie d’éventails. Le but de cette recherche est de fournir un aperçu de morphologie d’éventails vus d’en haut qui sont modifiés par des rivières axiales. Les éventails choisis pour cette étude devaient être dans une zone avec un espace adéquat, qui ne pouvaient pas être empiétés par d’autres éventails, et qui n’avaient pas de vallées conjointes près du point culminant. Les vallées vastes ...