Shore Ice Ride-Up and Pile-Up Features. Part I. Alaska's Beaufort Sea Coast.

摘要

Recent observations of shore ice pile-up and ride-up along the coast of the Alaska Beaufort Sea are presented. Information is given to show that sea ice movement on shore has overridden steep coastal bluffs and has thrust inland over 150 m, gouging into and pushing up mounds of beach sand, gravel, boulders and peat and, inland, the tundra material. The resulting ice scar morphology was found to remain for tens of years. Onshore ice movements up to 20 m are relatively common, but those over 100 m are very infrequent. Spring is a dangerous time, when sea ice melts away from the shore, allowing ice to move freely. Under this condition, driving stresses of less than 100 kPa can push thick sea ice onto the land. (Author)