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Titolo:
Geochemistry and K-Ar geochronology of the Late Pliocene-Pleistocene volcanism in the southern Andes (39-42 degrees S).
Autore:
Lara, L; Rodriguez, C; Moreno, H; de Arce, CP;
Indirizzi:
Serv Nacl Geol & Mineria, Santiago, Chile Serv Nacl Geol & Mineria Santiago Chile Geol & Mineria, Santiago, Chile
Titolo Testata:
REVISTA GEOLOGICA DE CHILE
fascicolo: 1, volume: 28, anno: 2001,
pagine: 67 - 90
SICI:
0716-0208(200107)28:1<67:GAKGOT>2.0.ZU;2-K
Fonte:
ISI
Lingua:
SPA
Soggetto:
CHILE; ROCKS; LAVAS; TECTONICS; ARGENTINA; COMPLEX; PLATE; ZONES; BELT;
Keywords:
K-Ar geochronology; geochemistry; eroded volcanoes; convergence velocity; pliocene-pleistocene; southern Andes.;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
37
Recensione:
Indirizzi per estratti:
Indirizzo: Lara, L Serv Nacl Geol & Mineria, Av Santa Maria 0104, Santiago, Chile Serv Nacl Geol & Mineria Av Santa Maria 0104 Santiago Chile hile
Citazione:
L. Lara et al., "Geochemistry and K-Ar geochronology of the Late Pliocene-Pleistocene volcanism in the southern Andes (39-42 degrees S).", REV GEOL CH, 28(1), 2001, pp. 67-90

Abstract

In the Andean Range, south of 39 degreesS, there is a suite of eroded volcanic centres that includes remains of vents or proximal, intermediate or distal volcanic facies. New geochronological K-Ar data show that their ages are in the Late Pliocene-Middle Pleistocene interval, and these eroded centres are equivalent to those located on the eastern side of the Andes. Geochemical patterns of pliocene-pleistocene volcanic centres are similar to those of the Quaternary volcanoes of this segment with a gradual variation toward the east in the La/Sm, Ba/La ratios and K even reaching backarc signature of the volcanoes far from the trench. Previous works, under the assumption that all volcanic rocks from the western side of the Andes were quaternary in age, have proposed a western migration of the volcanic arc to the westafter Pliocene. Instead, our geochronological and geochemical data show that the initial wide Late Pliocene-Middle Pleistocene arc narrows in the Quaternary time preserving the volcanic front. An important variation of the convergence velocity was recognized at the end of Pliocene and the authors propose that it is a first order factor on the geometry and location of the volcanic arc south of the 39 degreesS.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 31/05/20 alle ore 22:17:19