Thompson Glacier push moraineOne of the outstanding features of Thompson Glacier is a great push moraine caused by the advance of the tonge. It was investigated in detail by Kälin, M. 1971 (The active push moraine of the Thompson Glacier, Axel Heiberg Island Research Report, McGill University, Montreal). Some features of the moraine are best seen when there is snow, others, like the lakes within the moraine, are only prominent in summer. | |||
 Overview of the Expedition River valley, White Glacier (upper left), advancing Thompson Glacier and its push moraine (dark) from the summit of Little Matterhorn, May 1976. |  Thompson Glacier (far left) compresses proglacial gravel deposits which, since they are in permafrost condition, get thrusted up as angular blocks (tele-photo view from Gypsum Hill, May 1977). |  In June snowmelt increases and the dark moraine contrasts with the still snow-covered outwash plain in front of it (1976 aerial photo). |  Stereo anaglyph image of Thompson Glacier's push moraine. Red-blue or red-cyan glasses are needed to see the stereoscopic effect (from aerial photos June 1976). |
 Complex topography is caused by thrusting of frozen gravel deposits. Despite its dynamic development, the moraine topography remains stable long enough for meltwater streams to incise valleys. Ponds form since water seepage is hindered by the permafrost (July 2nd, 2008). |  Eastern part of the push moraine (aerial photo July 2nd, 2008): Here it is evident that the glacier surface is higher than the uplifted gravel blocks. This can be understood as a result of the smaller density of ice as compared to the gravel of the outwash plain. |  This aerial photo was taken under overcast sky conditions (13.7.2008). Whereas the complex topography is less obvious due to the absence of shadows, the great number of ponds dammed by uplifted gravel blocks becomes more evident. |  Thrusting and overthrusting of frozen gravel blocks mimiks much slower processes on a bigger scale in mountain orogeny. Note the gravel stratigraphy exposed in the cliffs of the tilted gravel blocks (aerial photo July 13th, 2008). |
| Photos Jürg Alean | |||