نوع مقاله : مقاله علمی پژوهشی
گروه ژئومورفولوژی، دانشکده جغرافیا و علوم محیطی، دانشگاه حکیم سبزواری، سبزوار، ایران
عنوان مقاله [English]
Pleistocene climate change is of particular importance given its timing and role in shaping the Earth's current landscape. The purpose of this study is to investigate the geomorphological evidence of Quaternary glaciers in the northeast of Binalood heights. The height of the border snow was estimated by Wright and Porter methods including height ratio, circus floor height and cumulative area ratio. Based on the shape of the curve lines in the topographic maps, 55 circuses were identified in the northern, eastern and western parts of the research area. Analysis of the estimated altitudes shows that the permanent boundary snow height in Porter and Wright method is more relevant to reality than other methods due to the reflection of the effect of unevenness on the boundary snow height. The analysis of the findings shows that this region has been under the rule of glacial formation system in cold periods. Thermal and humidity gradients were calculated according to the correlation between altitude and average annual temperature and altitude and annual rainfall. Findings show that the permanent border snow line with Wright and Porter methods is located at an altitude of 2600 and 2100 meters. According to this line and the drop in temperature of 0.7 degrees per 100 meters of altitude, the difference between the current temperature and the Pleistocene period was calculated to be equal to 6.4 degrees Celsius. The results showed that the amount of annual rainfall in the Pleistocene period was 130 mm more than the current average.