rift valley

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noun Geology.

a subsea chasm extending along the crest of a mid-ocean ridge, locus of the magma upwellings that accompany seafloor spreading.

Origin of rift valley

First recorded in 1890–95
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for rift valley

British Dictionary definitions for rift valley

rift valley


noun

a long narrow valley resulting from the subsidence of land between two parallel faults, often associated with volcanism. The East African Rift Valley is an example
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Science definitions for rift valley

rift valley


A long, narrow valley lying between two normal geologic faults. Rift valleys usually form where the Earth's lithosphere has become thin through extension associated with plate-tectonic processes. Unlike river valleys and glacial valleys that form primarily through erosional processes, rift valleys form by the subsidence of the intermediate land as the faults are pulled apart. They are on the order of thousands of kilometers long and wide. See more at normal fault.
The deep undersea valley located along the center of the mid-ocean ridge. It is associated with the crustal thinning and extensional forces that cause magma to upwell onto the ocean floor.
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