Alluvial Fan Development at Franklin Bluffs, Alaska

• Main Authors: Anderson, Gary S., Hussey, Keith M.
• Format: Text
• Language: English
• Published: UNI ScholarWorks 1962
• Subjects: Tundra; Alaska
• Online Access: https://scholarworks.uni.edu/pias/vol69/iss1/51; https://scholarworks.uni.edu/context/pias/article/2386/viewcontent/51_Alluvial_Fan_Development_at_Franklin_Bluffs.pdf

This paper is concerned with the developmental history of alluvial fans forming in a tundra climate. The study was made at Franklin Bluffs, Alaska (69° 48' - 70° 00' N, 148° 40' W), during the summer of 1961. The area is an ideal place in which to study the developmental history of alluvial fans in that so many stages are present in a relatively small area. A theoretical sequence of fan development was set up, illustrated by examples from the Franklin Bluffs, which show how certain characteristics of an alluvial fan, forming in a tundra climate, change as the sequence advances. The sequence was designated A, B, C, D, and E, where A is the youngest, near talus cone stage, and E is the oldest, near graded stage. Certain characteristics were found to constitute a continuum of changes in the sequence. The two most continuously changing factors are the difference in slope, between that of the drainage area and that of the fan, and the relative size of each fan -vs- drainage area. Also, in the progress of the sequence, the intensity of mass wasting decreases. Related to the type and intensity of mass-wasting and the amount and size distribution of surficial rock material and the amount and type of vegetation. The climax of the sequence is characterized by the approach to a well vegetated graded stage on which a permanent channel forms if sufficiently continuous discharge is present.