Campo De Esforços Plio-Pleistocênico Na Ilha Da Trindade (Oceano Atlântico Sul, Brasil) E Sua Relação Com Atectônica Regional

Abstract

PLIO-PLEISTOCENIC STRESS F1ELD IN THE TRINDADE ISLAND (SOUTHERN ATLANTIC OCEAN, BRAZIL) AND ITS RELATIOSHIP WITH THE REGIONAL TECTONICS The volcanic island of Trindade, of alkaline nature, is the emerged portion of a large volcanic building whose base is submerged about 5000 m depth. The analysis of the pattern of orientation of the Pliocene-Pleistocene dike swarm of the northeast portion of the island, as well as of the lengthening of phonolithic plugs, has allowed the determination of an NW direction of SH max (in the case corresponding to σ1) during the emplacement of the intrusive bodies, compatible with an ENE-WSW to E-W right-lateral binary. The direction determined for σ1 in the island is parallel to the larger axis of the volcanic building, suggesting the same tectonic control during its formation. On the other hand, the Vitória-Trindade Chain shows differentiated segments with NW-SE, NE-SW and E-W directions, probably corresponding to changes in the direction of σ1 during the Tertiary in this oceanic portion of the South American Plate. These changes are partly compatible with the variations verified in the adjoining continental portion of Southeastern Brazil. Differences in the depth of the basement to the north and to the south of the Vitória-Trindade Chain corroborate its behavior as a fracture zone, that would have acted as conduit for the magmatism associated with the Trindade Plume. The incompatibility verified between the expected direction of SH max during the Pliocene and Pleistocene in the Trindade Island and the direction of the studied dikes implies in a non-rigid behavior of this segment of the South American Plate.

An overview of the Mesozoic-Cenozoic magmatism and tectonics in Eastern Paraguay and central Andes (Western Gondwana): Implications for the composition of mantle sources

“…Following the interpretation of Ernesto et al (2002), the "hotspot tracks" of Walvis Ridge and Rio Grande Rise, as well as the Victoria-Trindade chain, may thus reflect the accommodation of stresses in the lithosphere during rifting (Ferrari and Riccomini, 1999), rather than continuous activity induced by mantle plumes beneath the moving lithospheric plates. Figure 3 shows a model reconstructed using analytical and thermo-barometric data for mantle xenoliths hosted in mafic-ultramafic lavas outcropping in the Andes and the Brazilian platform (Lucassen et al, 2005;Comin-Chiaramonti et al, 2009).…”

Richness and palaeo-zoogeographical significance of the benthic Ostracoda (Crustacea) from the oceanic Island of Trindade and Rocas Atoll, Brazil

“…Trindade Island corresponds to an emergent part of one of the volcanic edifices (Ferrari & Ricomini, 1999) with three peaks that rise to about 600 m above sea level. The island is surrounded by oceanic waters that reach 5,800 m depth.…”

Caracterização Da Morfologia Submarina Da Cadeia Vitória-Trindade E Áreas Adjacentes, Es, Com Base Na Batimetria Predita Do Topo Versão 14.1

“…Para o presente trabalho, os autores adotaram os dados do TOPO. Os trabalhos anteriores sobre a Cadeia Vitória-Trindade (e.g. Rangel 1998;Ferrari & Riccomini, 1999;Marques et al, 1999;Thomás-Filho & Rodrigues, 1999;Foder & Hanan, 2000;Lima et al, 2009) A introdução dos dados gravimétricos à confecção de mapa batimétrico, tal como Gomes et al (1997; Relatório interno da PETROBRAS, citado por Rangel, 1998), aprimorou drasticamente a resolução e, o Banco de Dogaressa foi expresso como a saliência morfológica composta de duas elevações. A versão adotada pelos autores tem resolução muito mais elevada (Figura 2B).…”