The Famatina complex (NW Argentina): back-docking of an island arc or terrane accretion? Early Palaeozoic geodynamics at the western Gondwana margin
Published:January 01, 2005
Hubert Miller, Frank Söllner, 2005. "The Famatina complex (NW Argentina): back-docking of an island arc or terrane accretion? Early Palaeozoic geodynamics at the western Gondwana margin", Terrane Processes at the Margins of Gondwana, A. P. M. Vaughan, P. T. Leat, R. J. Pankhurst
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This paper concerns sedimentary, volcanic, metamorphic and igneous rocks of the Sierra de Famatina and adjacent rock series in NW Argentina, for which the name ‘Famatina system’ has been used widely in the literature. It is suggested that this is renamed the ‘Famatina complex’, since ‘system’ is an internationally defined stratigraphical term. The Famatina complex is considered to have formed as an island arc on continental crust, represented in its diversity by metasediments and meta-volcanic rocks of the Sierra de Famatina, with a corresponding back-arc basin exposed in the medium- to high-grade metamorphic rocks of the adjacent Las Termas belt to the east. The Famatina complex was deposited in contact with the eastern Pampean complex (‘Pampia terrane’) at the western active continental margin of Gondwana in latest Proterozoic and Ordovician times. Deposition was, in part, accompanied by voluminous Ordovician magmatism of calc-alkaline composition. NNW-SSE-striking shear zones, dated previously at 402 ± 2 Ma, are interpreted as marking the final stage of collision of the island-arc/back-arc/continent complex. The dynamics of crustal block movements along the most prominent (TIPA) shear zone indicate overthrusting of the eastern Pampean series onto the western Famatina series and, hence, uplift and cooling of the eastern block must have occurred earlier than cooling of the western one. The composition of inherited components in Famatina metasediments and meta-granitoids argues for autochthonous arc-continent convergence rather than accretion of an exotic terrane.
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Terrane Processes at the Margins of Gondwana
The Australide orogen, the southern hemisphere Neoproterozoic to Mesozoic terrane accretionary orogen that forms the palaeo-Pacific margin of Gondwana, is one of the largest and longest-lived orogens on Earth. This book brings together a series of reviews and multidisciplinary research papers that comprehensively cover the Australides from the Tasman orogen of eastern Australia to the Neoproterozoic and Palaeozoic orogens of South America, taking in New Zealand and Antarctica along the way. It deals with the evolution of the southern Gondwana margin, as it grew during a series of terrane accretion episodes from the late Proterozoic through to final fragmentation in mid-Cretaceous times. Global perspectives are given by comparison with the Palaeozoic northern Gondwana margin and documentation of world-wide terrane accretion episodes in the Late Triassic-Early Jurassic and mid-Cretaceous. The Tasmanides of eastern Australia, and the terrane histories of New Zealand and souther South America are given comprehensive up-to-date reviews.