The Paraná-Etendeka traps (or Paraná and Etendeka Plateau; or Paraná and Etendeka Province) comprise a large igneous province that includes both the main Paraná traps (in Paraná Basin, a South American geological basin) as well as the smaller severed portions of the flood basalts at the Etendeka traps (in northwest Namibia and southwest Angola). The original basalt flows occurred 128 to 138 million years ago. The province had a post-flow surface area of 1.5 x 106 km² (580,000 miles²) and an original volume projected to be in excess of 2.3 x 106 km³.
The basalt samples at Paraná and Etendeka have an age of about 132 Ma, during the Valanginian stage of the Early Cretaceous. Indirectly, the rifting and extension are probably the origin of the Paraná and Etendeka traps and it could be the origin of the Gough and Tristan da Cunha Islands as well, as they are connected by the Walvis Ridge (Gough/Tristan hotspot). The seamounts of the Rio Grande Rise (25°S to 35°S) that go eastwards from the Paraná side are part of this traps system.
Interpretations of geochemistry, including isotopes, have led geologists to conclude that the magmas forming the traps and associated igneous rocks originated by melting of asthenosphic mantle due to the arrival of a mantle plume to the base of Earth's lithosphere. Then much of the magma was contaminated with crustal materials prior to their eruption. Some plutonic rocks related to the traps escaped crustal contamination reflecting more directly the source of the magmas in the mantle.
A type of rock called ignimbrite is found in some parts of the traps indicating explosive volcanic activity. The Paraná Traps possibly contains the site of the single largest explosive volcanic eruption known in Earth's history.
Video Paraná and Etendeka traps
See also
- Geology of Paraguay
- Geology of Uruguay
- Paraná Basin
- Uruguayan dyke swarms
Maps Paraná and Etendeka traps
References
- Peate DW (1997). "The Parana-Etendeka Province" (PDF). In Mahoney JJ, Coffin MF. Large Igneous Provinces: continental, oceanic, and planetary flood volcanism. Geophysical Monograph. 100. Washington, DC: American Geophysical Union. pp. 217-245.
External links
- "EMAGE: East Antarctic Margin Aeromagnetic and Gravity Experiment". Alfred Wegener Institute for Polar and Marine Research. Archived from the original on 2011-11-02.
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