Pingos in the Brooks Range, northern Alaska, U.S.A.

Some 70 pingos occur at 27 separate localities within and near the Brooks Range. The pingos are distributed through mountain valleys at altitudes up to 725 m and in terrain glaciated as recently as late Wisconsinan time. Most are open-system forms; possible closed-system pingos are present at only a single locality in a northern valley. Some pingos occur on thick alluvial or lacustrine sediments, but many seem to be localized above near-surface bedrock and possibly are related to northeast-trending fracture systems. Pingos are particularly abundant in the Koyukuk and Chandalar drainage systems of the south-central Brooks Range, where they may be associated with structural features of regional extent.