Large igneous province
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A large igneous province (LIP) is an extensive region of basalts resulting from flood basalt volcanism.
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[edit] Impact
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. Some LIP's lie on continental crust, while others lie beneath the oceans in so-called oceanic plateaus.
[edit] Theories of formation
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 arrives, 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. It is possible that both theories may lead to LIP formation.
[edit] Relationship to extinction events
Because a LIP may in several cases have occurred simultaneously with oceanic anoxic events and extinction events, it has been proposed that the volcanic byproducts of LIP formation may have had a profound and deleterious effect on the global environment.
[edit] Examples of LIPs
These are well documented Provinces in geological research
- Brazilian Highlands
- Caribbean-Colombian Plateau
- Central Atlantic Magmatic Province
- Deccan Traps
- Permian Emeishan Large Igneous Province
- Ethiopian Highlands
- Jameson Land
- Kerguelen Plateau
- Ontong Java Plateau
- Parana basalts
- Siberian Traps
- Columbia River Basalt Group
- Northern Cordilleran volcanic province
