@article { author = {goorabi, abolghasem and ehdaei, afsaneh and shabani araghi, arefe}, title = {Regeneration of Quaternary Climatic Conditions and Study of Glacial Range and Glacial Effects in Shirkouh of Yazd}, journal = {Quantitative Geomorphological Research}, volume = {8}, number = {1}, pages = {89-104}, year = {2019}, publisher = {Iranian Association of Geomorphology}, issn = {22519424}, eissn = {}, doi = {}, abstract = {Introductiondue to  the phenomenon of global warming that we are facing today, studies of glacier areas, and sub glacier and its effects are of particular importance, because by examining the  past climate,   future  theclimate change processes are better analyzed. One of the most important climatic heritage of the 4th era in Iran's highlands is glacier geomorphology and its glacier phenomenon. Climate change is one of the most characteristic features of the Quaternary period. Landforms have changed a lot during this period. Due to the warm and dry climatic conditions in central Iran and the presence of glacial landforms which shows the cold and wet climate in the past, we decided to study the current climatic conditions in the region with the aim of studying the past climate conditions.Location of study area  Shirkouh Highlands are located in 40 kilometers south-southwest of Yazd. Shirkouh is the most important infiltration mass of Central Iran. The mid-Jurassic Batulite of Shirkuh consists of three major units:  granodiorite, monzogranite and leukogranite. Shirkouh mountainous has created two different worlds of climate at a short distance in its environs. The location of Shirkouh elevations in the direction of northwest-southeast is like a long wall against the air masses and it is a temperature moderator in the region.Methodology  In the present study, first, by identifying the glacial landforms (circuses, moraines), the boundaries and extent of the last glacial period in the Shirkouh Mountains were determined and then by discovering their local-spatial relationship with climatic (temperature and precipitation) and morphological (elevation and direction and gradient) parameters, the temperature drop in the time of glaciers existence and the amount of ELA have been determined. In the first step, by using Digital Elevation Models (SRTM 30 meters from the American Geological Survey) and 10 meters DEM of the organization of mapping of Iran and the Google Earth image, the position of the circuses has been determined and then, their accuracy has been verified by field surveys. In the next step, the correlations between the quantitative characteristics of the glacial landforms with morphological (elevation, slope, slope direction) and climatic parameters (temperature and precipitation of14 weather stations of the region from 1985 to 2008) have been determined. Then, the amount of drop in temperature required to form a glacier in the last glacial period in the mountainous area has been calculated by comparing the current and the past ELA.Discussion and resultsDetection of glacial phenomenon of the Shirkouh area: Based on the circus reflected in topographic maps and satellite imagery (Google Earth) and field surveys in the Shirkouh mountains, 62 circuses were identified.  Due to the Wright method by passing 60% of the glacier circus location in the Shirkouh region, the Quaternary snow line is located at an altitude of 2491 m. This line represents the height of the zero-degree companion in the glacial period, by which we can reconstruct the past temperature conditions. Field observations in the Shirkouh region confirm the existence of glacial conditions such as circuses, glacier valleys and moraines. Based on the meteorological data and current climatic conditions, the current zero-degree temperature line is at 5438 m height, above the peak. According to the temperature equation, the past snow line is situated in the range of 22 centigrade degree of today’s temperature.  Regarding the paleo climate of the region: the distribution of circuses is different in Shirkouh altitudes. the highest number of circuses have northeast, north, west and east direction and the smallest of them have southeast and southern slope direction, respectively. The lowest circuses are situated in the range of 1800 to 1900 meters and the highest of them are located in the altitude range of 3800 to 3900 meters.ConclusionWith the studies of the prior researches, including the Hagedorn, the glacier processes at this region were identified at the height of 1925 to 2240 meters in the Quaternary   and Moraines have also been seen at a height of 1600 meters. According to the fact that during the past decades we are facing with the global warming, due to the amount of annual snowfall and the lack of glaciers feeding, in contrary to the Quaternary period, today, we are no facing with the glacial processes in the Central parts of Iran.due to  the phenomenon of global warming that we are facing today, studies of glacier areas, and sub glacier and its effects are of particular importance, because by examining the  past climate,   future  theclimate change processes are better analyzed. One of the most important climatic heritage of the 4th era in Iran's highlands is glacier geomorphology and its glacier phenomenon.}, keywords = {Glacial Processes,Snow line,Circus,Quaternary,Shirkouh of Yazd}, title_fa = {بازسازی شرایط اقلیمی کواترنر و بررسی محدوده یخچالی و آثار یخساری در شیرکوه یزد}, abstract_fa = {تغییرات اقلیمی از بارز‌ترین ویژگی‌های دوره کواترنر به شمار می‌رود. لندفرم‌های سطح زمین در این دوره دستخوش تحولات و تغییرات فراوانی شده است، با توجه به شرایط اقلیمی گرم و خشک در ایران مرکزی و وجود آثار و لندفرم‌های یخچالی که نشان دهنده شرایط اقلیمی سرد و مرطوبتر گذشته است ما را برآن داشت تا با هدف بررسی شرایط اقلیمی گذشته با شرایط اقلیمی حال حاضر در این منطقه بپردازیم. روش این پژوهش روش مشاهده‌ای و تحلیل مبتنی بر عملیات میدانی و سنجش از دور است، بنابراین داده‌هایی از جمله نقشه‌های توپوگرافی، مدل رقومی ارتفاع 30، 10 متر، تصاویر گوگل‌ارث، داده های GPS عملیات میدانی و داده‌های آماری اقلیم منطقه استفاده شده است.روابط ریاضی، مدل‌های تجربی و نرم افزارهای آماری و نقشه کشی از عمده ترین ابزارهای مفهومی این پژوهش را تشکیل می‌دهند. نتایج حاکی از آنست که خط برف مرز گذشته که به روش رایت محاسبه شده در ارتفاع 2491 متر قرار داشته و حداکثر پیشروی مورن‌ها در دامنه‌های غربی_شمال غربی تا ارتفاع 1980 متری و در دامنه جنوبی تا ارتفاع 2218 متری ثبت گردیده است..در شرایط اقلیمی حال حاضرخط هم‌دمای صفر درجه در ارتفاع 5440 متر و خط هم‌دمای 5 درجه یعنی (خط تعادل آب و یخ) در ارتفاع 4780 متری است و هردو بالاتر از قله قرار میگیرد، ارتفاع خط برفمرز دوره گذشته نیز براساس معادله دمایی در حد دمای 22 درجه امروز قرار دارد که نشان می‌دهد شرایط ایجاد فرآیندهای یخچالی و به تبع آن ایجاد لندفرم های یخچالی در منطقه شیرکوه یزد وجود ندارد.}, keywords_fa = {فرآیندهای یخچالی,برفمرز,سیرک,کواترنر,شیرکوه یزد}, url = {https://www.geomorphologyjournal.ir/article_91727.html}, eprint = {https://www.geomorphologyjournal.ir/article_91727_937816b250da4ea7ac8fd621ac4ccb73.pdf} }