LAUSR

From the early Quaternary, external factors such as climate change have altered the surface of the earth. The climatic changes have led to increase or decrease of glacier in highlands of Iran. The Alvand Mountain with an altitude of 3500 m is one of Iran’s highlands, which is located in Hamedan Provence. In order to the equilibrium line altitude (ELA) estimate during the last glacial maximum (LGM) in Alvand Mountain, this paper has used five methodological approaches such as Wright, slope– direction (SD), curvature coefficient (CC), the accumulation-area ratio (AAR), and terminus to head altitude ratio (THAR). After estimating ELA through the aforementioned methods, ELA in the northeast and southwest slopes were compared. According to the ELA estimates require the identification of Quaternary glacier circuses. The cirques in southwest slopes had an altitude between of 1700 to 2900 m and in northeast slopes had an altitude between of 2000 to 3400 m. The estimation of ELA of the whole study area turned out to be 2294 m. In the SD method, the average ELA in the northeast and the southwest slopes was 1960 and 2491 m, respectively. In the CC method, the ELA of the northeast and the southwest slopes was 2167 and 2099 m, respectively. The results of ELA analysis indicate that there are differences between the northeast and southwest slopes. According to Wright and CC methods, ELA in the northeast is higher than the southwest slopes, which is against the natural order of the environment. ELA estimated by AAR and SD methods in the northeast slopes is lower than in the southwest slopes. According to these two methods, there is about 500 m difference between the ELA of the northeast and southwest slopes. In this paper, in addition to the ELA, the water and ice equilibrium line altitude (WIELA) have been estimated. The field observation of the moraines revealed that WIELA during LGM was located at 1680 and 1776 m in the northeast and southwest slopes, respectively.