In geology, a depression is a landform sunken or depressed below the surrounding area. Depressions form by various mechanisms. Erosion-related: Blowout: a depression created by wind erosion typically in either a partially vegetated sand dune ecosystem or dry soils (such as a post-glacial loess environment). Glacial valley: a depression carved by erosion by a glacier. River valley: a depression carved by fluvial erosion by a river. Area of subsidence caused by the collapse of an underlying structure such as sinkholes in karst terrain. Sink: an endorheic depression generally containing a persistent or intermittent (seasonal) lake, a salt flat (playa) or dry lake, or an ephemeral lake. Panhole: a shallow depression or basin eroded into flat or gently sloping cohesive rock.Collapse…
