A large igneous province (LIP) is an extensive region of basalts resulting from flood volcanism. When created these regions often occupy a few million km2 and have volumes on the order of 1 million km3. In most cases, the majority of a LIP's volume is emplaced in less than 1 million years.
Many scientists argue that LIPs form as the result of mantle plumes that have only just arrived at the surface of the Earth. When a plume first arrive, they argue, the excess heat and chemical differences lead to an extended period of volcanism. Only subsequently does the plume cool and produce the kind of narrow channel of volcanism associated with features like the Hawaiian Islands. However, other scientists argue that large igneous provinces result from rifting and in particular the pulling apart of newly formed continental rifts without the need for deep seated plumes. Potentially both theories may lead to LIP formation.
Because in several cases LIPs have occurred simultanously with extinction events it has been proposed that the volcanic by products of LIP formation may have a sufficiently profound effect on the global environment to have caused these extinctions.
Several examples of LIPs
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