High Quality Content by WIKIPEDIA articles! Depression in geology is a landform sunken or depressed below the surrounding area. Depressions may be formed by various mechanisms, and may be referred to by a variety of technical terms. A basin may be any large sediment filled depression. In tectonics, it may refer specifically to a circular, syncline-like depression: a geologic basin; while in sedimentology, it may refer to an area thickly filled with sediment: sedimentary basin. A blowout is a depression created by wind erosion typically in either a desert sand or dry soil (such as a post- glacial loess environment). A graben is a down dropped and typically linear depression or basin created by rifting in a region under tensional tectonic forces.