TERRESTRIAL RECORD OF RAPID MASS MOVEMENTS IN THE SAWTOOTH RANGE, ELLESMERE ISLAND, NORTHWEST-TERRITORIES, CANADA

Widespread elastic deposits, 80-1800 m long, on the eastern side of th e Sawtooth Range are the result of debris flow and slushflow. Small hi llslope debris flows (10-10(3) m(3)), originating on talus slopes at t he mountain front and not associated with preexisting gullies, and lar ge channelized debris flows (10(3)-10(4) m(3)), debouching from basins within the mountains, are comparable morphologically to those in othe r high-latitude and high-altitude environments. Channelized deposits a re often modified by the effects of slushflow and fluvial activity. Pr ovisional lichen growth curves for the area were produced by correlati on of thallus size with the enlargement of ice-wedge polygon troughs. Lichenometry and aerial photograph interpretation were used to estimat e the age of deposits so that event frequencies and rates of geomorphi c work could be calculated. Vertical transport by rapid mass movements during the 20th Century averaged 17 x 10(3) Mg.m.a(-1).km(-2) (+/- ha lf an order of magnitude), corresponding to a rock denudation rate of 0.05 mm.a(-1) for the basins and peaks feeding the east-facing slopes. Channelized debris flow produced more than 70% of this transport. Sev eral of these large flows occurred in each of the three periods of 30- 35 years examined, so their recurrence intervals are substantially sho rter than values reported from locations in northern Scandinavia and S pitzbergen.