Rift 533365 223780032 2008-07-05T19:40:17Z EjsBot 6754156 robot Modifying: [[pt:Rifte]] {{otheruses}} {{redirect|Chasm}} {{unreferenced|date=November 2007}} {{cleanup-rewrite}} [[Image:Horst graben.jpg|right|frame|[[USGS]] image]] [[Image:Plates tect2 en.svg|thumb|Plates in the crust of the earth, according to the [[plate tectonics]] theory]] In [[geology]], a '''rift''' is a place where the [[Earth]]'s [[Crust (geology)|crust]] and [[lithosphere]] are being pulled apart<ref>http://www.mantleplumes.org/VM_DecompressMelt.html Decompressional Melting During Extension of Continental Lithosphere</ref> and are examples of [[extensional tectonics]].<ref>http://www.le.ac.uk/geology/art/gl209/lecture4/lecture4.html Plate Tectonics: Lecture 2</ref> Typical rift features are a central linear downdropped [[geologic fault|fault]] 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. Most rifts occur along the central axis of a [[mid-ocean ridge]], where new [[oceanic crust]] and lithosphere is created along a [[divergent boundary]] between two [[tectonic plate]]s. 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 (geology)|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]] * 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 ==References== {{Commonscat}} {{Reflist}} [[Category:Structural geology]] [[Category:Plate tectonics]] [[Category:Rift valleys]] [[als:Grabenbruch]] [[cs:Rift]] [[de:Grabenbruch]] [[es:Zona rift]] [[fr:Rift]] [[it:Rift]] [[nl:Rift]] [[pl:Ryft]] [[pt:Rifte]] [[ru:Рифт]] [[sk:Rift]] [[fi:Hautavajoama]] [[sv:Gravsänka]] [[uk:Рифтогенез]]