Origin of rock glaciers

OrigilZ of rock glaciersI should like to a dd some of my own o bservations on Arapaho R ock G lacier to those presented recentl y (Benedi ct, [973;Carrara, 1973) .D espite the general rejection of H owe's ( J 909) original view of the formation of rock glaciers in the San Juan M ountai ns of Colorado, there seems to be little d oubt that at least some rock-glacier materia l may be derived from rock fa lls or cliff falls .H owever, whether this material fa lls on top of an ex isting g lacier or becom es a rock g lacier by the addition of interstitia l ice still seems to be a contentious iss ue (Wha Il ey, 1974) ' There is considerable evidence showing that la rge-scale cliff-fall ( > 10 3 m 3) events a re important geomorphic occurrences in mounta inous a reas (Ra pp, 1960;Kjarta nsson, 1967; Abele, 1972) .The way in which the d ebris accumulated on top of a g lacier (as a ppears to be the case at Arapaho R ock G lacier) is important with respec t to the past mass balance of the glacier.