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Early evolution of the Proto-Andean margin of South America

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Rapela, C. W. and Pankhurst, Robert J. and Casquet, César and Baldo, Edgardo G. (1998) Early evolution of the Proto-Andean margin of South America. Geology, 26 (8). pp. 707-710. ISSN ISSN 0091-7613

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Official URL: https://pubs.geoscienceworld.org/geology/issue/26/8




Abstract

From a detailed study of a 500 km transect in the Sierras Pampeanas, central-west Argentina, two pre-Silurian tectono-magmatic episodes are recognized and defined, each culminating n micro-continental collisions against the proto-Andean margin of Gondwana. The Pampean orogeny started in Early Cambrian time with short-lived ubduction, indicated by ca. 535 Ma alc-alkaline granitoids. Following Pampean terrane collision, burial to granulite facies conditions (ca. 9 kbar) generated widespread migmatites and ca. 520 Ma highly peraluminous granites in the Eastern Sierras Pampeanas. After brief quiescence, a second major episode, the amatinian orogeny, started with subduction ca. 490 Ma, forming a wide continental arc and nsialic backarc basin. This heralded the approach of Laurentia to Gondwana, during which the Precordillera terrane separated from the southern Appalachian region, finally colliding with Gondwana in Silurian–Devonian time.


Item Type:Article
Uncontrolled Keywords:Tectónica, Gondwana, Sudamérica, Andes, Cámbrico
Subjects:Sciences > Geology > Geodynamics
Sciences > Geology > Petrology
ID Code:45585
Deposited On:28 Nov 2017 08:26
Last Modified:28 Nov 2017 08:26

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