Evolution of lakes and basins in northern Alaska and discussion of the thaw lake cycle

• Published in: Journal of Geophysical Research. F. Earth Surface 2007-05, Vol.112 (F2)
• Main Authors: Jorgenson, MTorre, Shur, Yuri
• Format: Article
• Language: English
• Subjects: Freshwater
• ISSN: 0148-0227
• DOI: 10.1029/2006JF000531,2007

We evaluated the development of lake basins on the central coastal plain of northern Alaska on the basis of topographic profiles, soil and ground ice surveys, radiocarbon dating, photogrammetric analysis, and regional comparisons. Our analysis reveals that lake evolution is much more complex and less cyclic than theorized by previous investigations. In the area we studied, there was insufficient ground ice in the oldest terrain to form thaw lakes, the aggradation of ice in the margins of drained lake basins was insufficient to heave the surface up to near original topographic conditions, and the process occurs at too slow a rate for a "thaw lake cycle" to develop within the Holocene. Accordingly, we revised the conceptual model of lake and basin development to be consistent with the patterns and process we observed on the extensive sand sheets underlying most of the coastal plain. Developmental stages include (1) initial flooding of depressions to form primary lakes, (2) lateral erosion, with sorting and redistribution of sediments, (3) lake drainage as the stream network expands, (4) differential ice aggradation in silty centers and sandy margins, (5) formation of secondary thaw lakes in the heaved centers of ice-rich basins and infilling of ponds along the low margins, and (6) basin stabilization.