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A valley is an elongated low area often running between hills or mountains and typically containing a river or stream running from one end to the other. Most valleys are formed by erosion of the land surface by rivers or streams over a very long period. Some valleys are formed through erosion by glacial ice. These glaciers may remain present in ...
The glacier visible at the head of the valley is the last remnant of the formerly much more extensive glacier which carved it. U-shaped valley with lake in Myklebustdalen, Nordfjord, Sogn og Fjordane, Norway. U-shaped valleys, also called trough valleys or glacial troughs, are formed by the process of glaciation.
The glacial history of the valley is significant, with evidence of ancient ice movement shaping its geography. The valley's upper reaches near Cradle Mountain contain glacial moraines and U-shaped valleys formed during the Pleistocene epoch. [1] These features make the Mersey Valley an important area for studying Tasmania’s geological past.
Mesopotamia was one of the earliest river valley civilizations: it started to form around 4000 BCE. The civilization was created after regular trading relationships started between multiple cities and states around the Tigris and Euphrates Rivers. Mesopotamian cities became self-run civil governments.
Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width, are characterized by a distinct 'headscarp' or 'headwall' and progress by headward (i.e., upstream) erosion. Gullies are commonly related to intermittent or ephemeral water flow, usually associated with localised intense or protracted rainfall ...
A rift valley near Quilotoa, Ecuador. The Ottawa-Bonnechere Graben Þingvallavatn. A rift valley is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear depression may ...
A cirque (French:; from the Latin word circus) is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from Scottish Gaelic: coire, meaning a pot or cauldron) [1] and cwm (Welsh for 'valley'; pronounced). A cirque may also be a similarly shaped landform arising from fluvial erosion.
They can be as long as 100 km (62 mi), 4 km (2.5 mi) wide, and 400 m (1,300 ft) deep. Tunnel valleys were formed by subglacial erosion by water and served as subglacial drainage pathways carrying large volumes of meltwater. Their cross-sections often exhibit steep-sided flanks similar to fjord walls. They presently appear as dry valleys, lakes ...