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| Gutscher, Marc-andre; Olivet, Jean-louis; Aslanian, Daniel; Eissen, Jp; Maury, Rene. |
| Since flat subduction of the Nazca Plate beneath Peru was first recognized in the 1970s and 1980s a satisfactory explanation has eluded researchers. We present evidence that a lost oceanic plateau (Inca Plateau) has subducted beneath northern Peru and propose that the combined buoyancy of Inca Plateau and Nazca Ridge in southern Peru supports a 1500 km long segment of the downgoing slab and shuts off arc volcanism. This conclusion is based on an analysis of the seismicity of the subducting Nazca Plate, the structure and geochemistry of the Marquesas Plateau as well as tectonic reconstructions of the Pacific¿Farallon spreading center 34 to 43 Ma. These restore three sub¿parallel Pacific oceanic plateaus; the Austral, Tuamotu and Marquesas, to two Farallon... |
| Tipo: Text |
Palavras-chave: Nazca Plate; Subduction; Nazca Ridge; Peru; Reconstruction. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/1999/publication-360.pdf |
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| Juteau, T; Eissen, Jp; Francheteau, J; Needham, David; Choukroune, P; Rangin, C; Seguret, M; Ballard, Rd; Fox, Pj; Normark, Wr; Carranza, A; Cordoba, D; Guerrero, J. |
| Fort y basaltic rocks collected by submersible during the "Cyamex" expedition (1978) on the East PacifIc Rise at 21 oN, a moderately fast spreading segment (6 cm/year opening rate) of the mid-ocean ridge, consist of angular pillow fragments and glass buds, sheet-flow slabs and samples of columnar pillars standing in collapsed fossillava pools. Most of the rocks are from the crestal are a of the Rise. The collection shows a striking petrographic homogeneity wh en compared with the range of basalts found on other segments of midocean ridges: olivine-phyric, or highly plagioclase-phyric rocks, so common in the slowspreading "Famous" are a in the Atlantic, are absent. All samples are typical lowpotassium oceanic tholeiites with a limited fractionation trend.... |
| Tipo: Text |
Palavras-chave: Dorsale Est-PacifIque Pétrologie des basaltes sous-marins Coussins; Laves fluides; Piliers Générations de cristaux Globules de sulfure East Paciflc Rise Petrology of submarine basalts Pillows; Sheet flows; Pillars Generations of crystals Sulphide globules. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/00323/43430/43112.pdf |
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