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Using these three areas as a case study, the team confirmed that continental rifting caused slow-moving mantle waves to roll toward the heart of the continent.
The Baikal Rift Zone in eastern Russia; The Red Sea Rift; The Aden Ridge along the southern shore of the Arabian Peninsula; The Carlsberg Ridge in the eastern Indian Ocean; The Woodlark Basin undergoing transition from continental rifting to sea floor spreading to the east of New Guinea; The Gorda Ridge off the northwest coast of North America
The Midcontinent Rift System (MRS) or Keweenawan Rift is a 2,000 km (1,200 mi) long geological rift in the center of the North American continent and south-central part of the North American plate. It formed when the continent's core, the North American craton , began to split apart during the Mesoproterozoic era of the Precambrian , about 1.1 ...
Many flood basalts are associated with rift valleys, are located on passive continental plate margins, or extend into aulacogens (failed arms of triple junctions where continental rifting begins.) Flood basalts on continents are often aligned with hotspot volcanism in ocean basins. [ 33 ]
Most examples come from areas of active continental rifting such as the Basin and Range Province. Bimodal volcanism has also been described from areas of transtension, [2] the early phases of back-arc basin formation [3] and in the products of both continental and oceanic hotspots (e.g. Yellowstone, Anahim and the Canary Islands). [4] [5] [6]
Continental rifting commonly follows flood basalt volcanism. Flood basalt provinces may also occur as a consequence of the initial hot-spot activity in ocean basins as well as on continents. It is possible to track the hot spot back to the flood basalts of a large igneous province; the table below correlates large igneous provinces with the ...
Continental rifting forms new ocean basins. Eventually the continental rift forms a mid-ocean ridge and the locus of extension moves away from the continent-ocean boundary. The transition between the continental and oceanic lithosphere that was originally formed by rifting is known as a passive margin.
Rifting may lead to continental breakup and formation of oceanic basins. Successful rifting leads to seafloor spreading along a mid-oceanic ridge and a set of conjugate margins separated by an oceanic basin. [14] Rifting may be active, and controlled by mantle convection. It may also be passive, and driven by far-field tectonic forces that ...