Studies On Crescentic Fractures and Crescentic Gouges with the Help of Close-range Photogrammetry

Abstract

Abstract Studies on cresceatic fractures and crescentic gouges were carried out in the central part of the Alpine piedmont glaciation and the Quaternary Alpine mountain ice sheet. The test sites were situated in the pro-glacial area of the Hornkees south Berliner Hütte (Oberer Zemmgrund, Zillertal, Tyrol, Austria). This is also the area of the former confluence with another glacier which flowed at about 90° to Hornkees during the late-glacial period. It was therefore possible to make a comparison between different older glacier systems, different flow directions, and different ice thicknesses. About 12 000 minor features were measured by close-range photogrammetry; the result was 240 pairs of stereophotographs which were interpreted on first-order equipment. The single forms were registered point by point by coordinates. It was therefore possible to obtain three-dimensionally registered forms. One important result was that the late-glacial and the post-glacial glaciers of the Zemmgrund produced minor features with a large variation in size. A further result was the definition of possible glacier-flow directions by interpretation of the different directions of crescentic fractures and crescentic gouges. By this means it was possible to obtain several working reconstructions of the late- and post-glacial stream lines of the merged glaciers.