USGS image

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 and lithosphere are being pulled apart, an example of extensional tectonics. The United States Geological Survey ( USGS) is a scientific agency of the United States government. Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere Geology (from Greek γη gê, "earth" and λόγος Logos, "speech" lit EARTH was a short-lived Japanese vocal trio which released 6 singles and 1 album between 2000 and 2001 In Geology, a crust is the outermost solid shell of a planet or moon The lithosphere (IPA, from the Greek λίθος for "rocky" + σφαίρα for "sphere" is the solid outermost shell of a rocky Planet. Extensional tectonics is concerned with the structures formed and the tectonic processes associated with the stretching of the crust or Lithosphere. Typical features are a central linear downdropped 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. In Geology a fault, or fault line, is a planar rock fracture which shows evidence of relative movement A graben is a depressed block of land bordered by parallel faults Graben is German for ditch. A rift valley is a linear-shaped lowland between highlands or mountain ranges created by the action of a geologic Rift or fault. The axis of the rift area commonly contains volcanic rocks and active volcanism is a part of many but not all active rift systems. Rifts are distinct from Mid-ocean ridges, where new oceanic crust and lithosphere is created by seafloor spreading. A mid-ocean ridge or mid-oceanic ridge is an underwater Mountain range typically having a valley known as a Rift running along its axis formed by Oceanic crust is the part of Earth's Lithosphere that surfaces in the Ocean basins Seafloor spreading occurs at Mid-ocean ridges where new Oceanic crust is formed through volcanic activity and then gradually moves away from the ridge In rifts, no crust or lithosphere is produced. If rifting continues, eventually a mid-ocean ridge may form, marking a divergent boundary between two tectonic plates. In Plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a Plate tectonics (from Greek τέκτων tektōn "builder" or "mason" describes the large scale motions of Earth 's Lithosphere Failed rifts, which may be ancient or modern, are where continental rifting began, but then failed to continue to the point of break-up. Typically the transition from rifting to spreading develops as three converging rifts over a hotspot. In Geology, a hotspot is a location on the Earth's surface that has experienced active volcanism for a long period of time Two of these evolve to the point of seafloor spreading, while the third ultimately fails, becoming an aulacogen. In Geology, an aulacogen is a failed arm of a Triple junction of a Plate tectonics rift system

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 East African Rift is part of the larger Great Rift Valley. The Red Sea Rift is a spreading center between two Tectonic plates the African Plate and the Arabian Plate. Baikal Rift Zone is a Divergent plate boundary centered beneath Lake Baikal in southeastern Russia. Lake Baikal (о́зеро Байка́л Ozero Baykal, ˈozʲɪrə bʌjˈkɑl Байгал нуур Baygal nuur) is in Southern Siberia in Russia
• 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