Document Type : علمی- پژوهشی
Authors
Abstract
It is a very short time that the Quaternaries period in Geology and physical Geography's knowledge has occupied a very important place. During this period, the earth has suffered consecutive freezing that has been accompanied by tides and alternate erosion and sedimentation. Sedimentary successions have recorded valuable evidence of changes with very accurate details. The study of these sediments has been the main way of the past event of earth's new technology such as fixing the snowline depression, the boundary of extension and also, the study of region changes of that period. Recently, a series of studies have been done and reported in western Alborz. In a detailed scale, however, there is no word of boundaries of glacial extension, the existence of temperature in the period of Quaternaries and snowline depression. To fill this gap, the cirque-floor altitude is the best method for reconstruction of the Wurm snowline. This research is a descriptive survey. The research results prove that siyalan glacier tongue has a maximum height of 1200 m and exactly up to the present location of Assal Mahaleh village. The altitude of old snowline was 2100 m and the average of temperature in the highest cirque at present in this region is -4oC and the forms such as glacier cirques, drifts and wurm region changes in this zone are among the most important phenomena related to the Wurm climate changes.
Key words: Quaternary, Snowline, glaciers, Siyalan Mountain
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