Rift

Gulf of Suez rift showing main extensional faults

In geology, a rift or chasm is a place where the Earth's crust and lithosphere are being pulled apart^[1] and is an example of extensional tectonics.^[2]

Typical rift features are a central linear downfaulted segment, called a graben, with parallel normal faulting and rift-flank uplifts on either side forming a rift valley, where the rift remains above sea level. The axis of the rift area commonly contains volcanic rocks, and active volcanism is a part of many, but not all active rift systems.

Major rifts occur along the central axis of mid-ocean ridges, where new oceanic crust and lithosphere is created along a divergent boundary between two tectonic plates.

Failed rifts are where continental rifting began, but then failed to continue to the point of break-up. Typically the transition from rifting to spreading develops at a triple junction where three converging rifts meet over a hotspot. Two of these evolve to the point of seafloor spreading, while the third ultimately fails, becoming an aulacogen.

Examples

The East African Rift
The Red Sea Rift
The Baikal Rift Zone, the bottom of Lake Baikal is the deepest continental rift on the earth.
The Gulf of Suez Rift
Lake Timiskaming in Temiskaming Shores, Ontario
Throughout the Basin and Range Province in North America
The Rio Grande Rift in the southwestern US
The rift zone that contains the Gulf of Corinth in Greece
The Reelfoot Rift, an ancient buried failed rift underlying the New Madrid Seismic Zone in the Mississippi embayment
The Rhine Rift, in south western Germany, known as the Upper Rhine valley, part of the European Cenozoic Rift System
The Taupo Volcanic Zone in the north east North Island of New Zealand
The Oslo Graben in Norway
The Ottawa-Bonnechere Graben in Ontario and Quebec
The Northern Cordilleran Volcanic Province in British Columbia, Yukon and Alaska
The West Antarctic Rift in Antarctica
The Midcontinent Rift System, a late Precambrian rift in central North America
The Fundy Basin, a Triassic rift basin in southeastern Canada
The Narmada Rift valley in peninsular India

References

^ Decompressional Melting During Extension of Continental Lithosphere, Jolante van Wijk, MantlePlumes.org
^ Plate Tectonics: Lecture 2, Geology Department at University of Leicester

[1] Decompressional Melting During Extension of Continental Lithosphere, Jolante van Wijk, MantlePlumes.org

[2] Plate Tectonics: Lecture 2, Geology Department at University of Leicester

[1]

[2]

Examples

See also

References