The early Palaeozoic Orogen in the Central Andes: a non-collisional orogen comparable to the Cenozoic high plateau?
Published:January 01, 2005
Friedrich Lucassen, Gerhard Franz, 2005. "The early Palaeozoic Orogen in the Central Andes: a non-collisional orogen comparable to the Cenozoic high plateau?", Terrane Processes at the Margins of Gondwana, A. P. M. Vaughan, P. T. Leat, R. J. Pankhurst
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The subduction orogeny of the Central Andes, which created the Cenozoic Altiplano-Puna high plateau, shares many geological features with the early Palaeozoic Orogen at the western margin of South America. The presently available datasets for both orogens are compared. The similarities are a large-scale high temperature metamorphism, which was active in the Palaeozoic Orogen over a geological long period of time in the order of 100 Ma and which is active now in the crust of the Cenozoic plateau. It produced abundant granitoid melts from the crust during the Palaeozoic as well as during the Andean Orogen. The main contribution to granitoid magmatism is recycling of felsic crustal material with only minor additions from the mantle. Transport of deep parts of the crust into the erosion level did not occur in both orogens and, in both orogens, large-scale nappe tectonics typical for collision orogens are absent. Based on the similarities of the two orogens it is argued that the early Palaeozoic Orogen is a non-collisional orogen. Indications for terrane accretion are absent in the development of the high-grade metamorphic and igneous basement. The early Palaeozoic Orogen is an analogue for the presently active continental margin and, thus, allows the extrapolation of features which cannot be observed in the Andean Orogen.
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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.