Document Type : Research Paper

Author

• Hamid Malmirian (Translator)

Abstract

Today, most of the water found on the surface of the earth is in lakes and oceans in the form of liquid. Almost two percent of water is in the form of solid as ice at high altitudes and geographic latitudes. About ten percent of the earth’s surface is covered by glaciers. Over a million years or more, the glaciers have consistently been on over 30% of the earth's surface. The main era took place during periods when the earth’s climate was colder than its current state. The formation of glaciers occurred both in the form of formation of a "glacier in the valley” in which ice occupied the mountainous valleys, and in the form of continental glaciers in which large parts of several continents were covered with ice with a thickness of three kilometers. This arouses humans into thought and helps them describe the advancing ability of a glacier to cut land features along its course. We rationally discuss the formation of sedimentary lands due to formation of continental glaciers. Four distinct stages have been identified in the United States. The last ice age has been during the formation of the Wisconsin Glaciation, which occurred within a time interval between 70,000 and almost 10,000 years ago.