Push Moraine of the Thompson Glacier on the Axel Heiberg Island in the Canadian Arctic

Abstract

As a technical term of glacial geomorphology, “Push Moraine” has not been introducd to us in any textbook and in any scientific article in Japan until now. The author has participated in the Pre-Congress field tour that was guided by Prof. Fritz Muller (E. T. H. in Zürich) to the Axel Heiberg Isl. of the Canadian High Arctic in the summer of 1972 when the Congress of I. G. U. (International Geographic Union) has been held in Montreal, Canada. Then he has observed at a short distance the push moraine in front of the Thompson Glacier on the Axel Heiberg Isl. Along the shore of Colour Lake near the snout of the Thompson Glacier, there is an observation station that belongs to McGill University in Montreal. Since 1959, during the summer period, a number of scientists have been engaged in the observational works for geomorphology, glaciology, climatology etc.The push moraine of the Thompson Glacier is known already as a famous example in the world. So, the author should like to introduce and to describe that push moraine on the basis of the report of Dr. M. Kälin, that is, “M. Kälin (Dec., 1971) : The Active Push Moraine of the Thompson Glacier, pp. 68, Glaciology, No. 4, Axel Heiberg Island Research Reports, McGill University, Montreal”.A few examples in connection with the characteristics about the push moraine of the Thompson Glacier would be shown as follows.1) A push moraine is a ridge in the front of glacial tongue, and is formed by the pressure of pushing up in advance of a glacier.2) The push moraine consists of permanently frozen materials of outwash.3) The glacier thrusts over the push moraine and the push moraine thrusts over the undeformed outwash plain. And the many thrust surfaces can be observed within the push moraine.4) The advancing velocity of the glacial front is 7.1 cm/day and 26 m/year. The push moraine is advancing to the center of the Expedition River Valley with 2.7 cm/day of the surface velocity at the outermost rim.5) 19 push moraines on Axel Heiberg Isl. and 16 push moraines on Ellesmere Isl. are identified by air-photo interpretation. Among the glaciers having a push moraine, 7 glaciers are advancing and 7 glaciers are stationary and 21 glaciers are retreating.