Trindade hotspot

The Trindade hotspot is a working hypothesis supposing that the submarine volcanic chain Vitória-Trindade, off the eastern coast of Brazil in the southern Atlantic Ocean, is a volcanic hotspot chain. It was considered that the supposed hot-spot should be responsible for the creation of the east-west trending Vitória-Trindade seamount chain, which includes the Trindade and Martim Vaz archipelago at its easternmost end. Trindade, a small island in the archipelago, is the hotspot's most recent eruptive center.

This ideas was based on the geochemical data, especially of the highly silica-undersaturated alkaline ultramafic rocks of the Trindade Island and Martim Vaz Island. The isotopic data is OIB-type, which is favourable to the hot-spot hypothesis. However, the volcanic chain direction is E-W and the absolute motion vector of the South America Plate is NW. Therefore, the volcanic chain cannot be a hot-spot chain. Recent research papers, such as Skoletnev, Peyve & Truko 2010 and Motoki, Motoki & Melo 2012, proposed that the hot mantle penetrated horizontally along the Vitória-Trindade fracture zone which is present in the lithospheric mantle. Because of the same reason, the Fernando de Noronha Volcanic chain also is not a hot-spot chain. On the other hand, the NW-SE magmatic alignments, such as the Cruzeiro do Sul Chain, Bahia Chain, and Macau-Queimado, are considered to be hot-spot chains.

Hotspots
The Trindade hotspot is marked 41 on the map

References

  • Motoki, A.; Motoki, K. F.; Melo, D. P. (2012). "Caracterização da morfologia submarina da Cadeia Vitória-Trindade e áreas adjacentes, ES, com base na batimetria predita do TOPO versão 14.1". Revista Brasileira de Geomorfologia (in Portuguese). 13 (2): 151–170. ISSN 2236-5664. Retrieved May 2015. Check date values in: |accessdate= (help)
  • Skoletnev, S. G.; Peyve, A.; Truko, N. N. (2010). "New data on the structure of the Vitoria-Trindade seamount chain (western Brazil basin, South Atlantic)". Doklady Earth Sciences (in Portuguese). 431 (2): 435–440. doi:10.1134/S1028334X10040057.

Coordinates: 20°31′30″S 29°19′30″W / 20.52500°S 29.32500°W

Hotspot (geology)

In geology, the places known as hotspots or hot spots are volcanic regions thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle. Their position on the Earth's surface is independent of tectonic plate boundaries. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths. This hypothesis considers the term "hotspot" to be a misnomer, asserting that the mantle source beneath them is, in fact, not anomalously hot at all. Well-known examples include the Hawaii, Iceland and Yellowstone hotspots.

Trindade and Martin Vaz

Trindade and Martin Vaz (Portuguese: Trindade e Martim Vaz, pronounced [tɾĩˈdadʒi i mɐʁˈtʃĩ ˈvas]) is an archipelago located in the Southern Atlantic Ocean about 1,100 kilometres (680 miles) east of the coast of Espírito Santo, Brazil, which it constitutes a part of. The archipelago has a total area of 10.4 square kilometres (4.0 square miles) and a population of 32 (Brazilian Navy personnel). The archipelago consists of five islands and several rocks and stacks; Trindade is the largest island, with an area of 10.1 square kilometres (3.9 square miles); about 49 kilometres (30 miles) east of it are the tiny Martin Vaz islets, with a total area of 0.3 square kilometres (30.0 hectares) .

The islands are of volcanic origin and have rugged terrain. They are largely barren, except for the southern part of Trindade. They were discovered in 1502 by Portuguese explorer Estêvão da Gama and stayed Portuguese until they became part of Brazil at its independence in 1822. From 1895 to 1896, Trindade was occupied by the United Kingdom until an agreement with Brazil was reached. During the period of British occupation, Trindade was known as "South Trinidad."

The islands are situated some 2,100 kilometres (1,300 miles) southwest of Ascension Island and 2,550 kilometres (1,580 miles) west of Saint Helena, while the distance to the west coast of Africa is 4,270 kilometres (2,650 miles).

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