Artículo
Basement evolution of the Sierra de la Ventana Fold Belt: New evidence for Cambrian continental rifting along the southern margin of Gondwana
Fecha de publicación:
07/2003
Editorial:
Geological Society Publications House
Revista:
Journal of the Geological Society
ISSN:
0016-7649
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
U-Pb sensitive high-resolution ion microprobe data together with geochemical and Nd isotope analyses obtained in the basement complex of the Sierra de la Ventana Fold Belt indicate that the Early Palaeozoic passive margin history of the basin followed Cambrian magmatism related to rifting in a 600 Ma Neoproterozoic crust. The Cambrian episode started with intrusion of 531 ± 4 and 524 ± 5 Ma A- and I-type granites derived from a dehydrated infracrustal source (cNd530 - 3.1 to -5.9), and culminated with eruption of high-Zr peralkaline spherulitic rhyolites derived from an undepleted lithospheric mantle (509 ± 5 Ma; cNd509 +0.5 to +1.0). These rift-related magmatic rocks were covered by shelf sediments deposited along a once-continuous passive margin, encompassing the Sierra de la Ventana Fold Belt, the Cape Fold Belt, the Falkland/Malvinas microplate and the Ellsworth Mountains block in Antarctica. The Cambrian rifting event defined the outline shape of the southern part of Gondwana, and can be regarded as the initiation of the supercontinent stage, which lasted until Jurassic break-up. The conjugate continental fragments separated from Gondwana during the Cambrian rifting could be the source for microcontinents with c. 1000 Ma basement rocks that collided with the proto-Andean margin during Ordovician-Silurian times.
Palabras clave:
Geochronology
,
Gondwana
,
Granites
,
Rifting
,
U-Pb Shrimp
Archivos asociados
Licencia
Identificadores
Colecciones
Articulos(CCT - LA PLATA)
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos de CTRO.CIENTIFICO TECNOL.CONICET - LA PLATA
Articulos(INGEOSUR)
Articulos de INST.GEOLOGICO DEL SUR
Articulos de INST.GEOLOGICO DEL SUR
Citación
Rapela, Carlos Washington; Pankhurst, R. J.; Fanning, C. M.; Grecco, Laura Edith; Basement evolution of the Sierra de la Ventana Fold Belt: New evidence for Cambrian continental rifting along the southern margin of Gondwana; Geological Society Publications House; Journal of the Geological Society; 160; 4; 7-2003; 613-628
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