Geomorphological and Sedimentological evidence of alpine glaciers in the Zagros Mountains, Dinevar, Iran

Abstract

The altitude to which the past glaciers had been extended during the last glacial period in Dinevar Basin, western Iran, can be estimated based on glacier-geomorpic evidence such as cirques, U-shaped valleys, and the moraines in lowlands. This study estimates the elevation of snowline during this period for the basin as the objective of the research. Topographic and geologic maps, Landsat images and ASTER elevation data, climatic statistics and the sediment samples gathered by field survey were used as the material of this study. According to Wright method, the difference between the elevation of the highest and the lowest cirques and the altitude where have 60% of cirques have been obtained. The snowline altitude has produced the isotherm map of the basin during the last cold period. The results of the research have indicated that the permanent snowline during the last glacial period was 2820 meters above sea level (a.s.l.) and that the average temperature in the basin had been 5.8 degrees less than the present. The poor sorting of the samples with considerable angularity suggests that the sediments in low lands of the basin have been deposited by peri-glacial flooding.  It can be concluded that the performance of glaciers in the basin is confirmed.

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