Early Paleozoic structural and metamorphic evolution of the Transpatagonian Orogen related to Gondwana assembly
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ORIGINAL PAPER
Early Paleozoic structural and metamorphic evolution of the Transpatagonian Orogen related to Gondwana assembly Pablo D. González1 · Maximiliano Naipauer2 · Ana M. Sato3 · Ricardo Varela3 · Miguel A. S. Basei4 · María Cecilia Cábana5 · Silvio R. F. Vlach4 · Martín Arce6 · Martín Parada6 Received: 3 March 2020 / Accepted: 23 September 2020 © Geologische Vereinigung e.V. (GV) 2020
Abstract The temporal and spatial relationships between polyphase folding and faulting, regional metamorphism, and granitoids intrusions are discussed for the low-grade basement rocks of the El Jagüelito Formation from the eastern North Patagonian Massif, Argentina, at the inferred western Gondwana margin. As a result of the tectonometamorphic and magmatic events, a late Cambrian-early Ordovician orogenic belt is revealed in northern Patagonia and shall be named the Transpatagonian orogen. It is an NW–SE-trending belt traced from the extra-Andean North Patagonian Cordillera region via the eastern North Patagonian Massif up to the Atlantic coast in the east. The early Paleozoic Transpatagonian orogen is the result of compressional tectonics, also showing a significant dextral shearing, and regional metamorphism leading to the development of a fold-and-thrust belt with an anticlockwise P–T–D-time path. The double-sided orogen is divided into three tectonometamorphic zones bounded by NW–SE trending major faults. Regional comparisons of our results in the present contribution together with available geological data, allow characterizing the orogen as part of a paired metamorphic belt system, with an outboard low-P/high-T belt (northern Patagonia terrane) and a parallel, inboard medium-P/T belt of Barrowian type (Famatinian Orogen on Gondwana margin), respectively. They are juxtaposed tectonically along with the contact of the suture Huincul Fault Zone. The Transpatagonian orogen was implanted along the southernmost Gondwana margin during the final stages of the supercontinent assembly in the early Paleozoic. The tectonism of the Permian Gondwanide orogeny reworked the Transpatagonian orogen. Keywords Fold-and-thrust belt · Low-grade metamorphism · Anti-clockwise P–T-time path · Early Paleozoic · Patagonia
Introduction After the early Neoproterozoic break-up of the Rodinia supercontinent, the dispersed Mesoproterozoic crustal fragments were gradually reassembled to form Gondwana by the Ediacaran-early Paleozoic. During the assembly, the Terra Australis orogenic belt implanted along the (paleo) Pacific-Iapetus oceanic margin of Gondwana between Australia and South America (Cawood 2005). The orogen has a protracted history of ongoing subduction along with inboard continental margin sequences that occur, outboard of which Electronic supplementary material The online version of this article (https://doi.org/10.1007/s00531-020-01939-0) contains supplementary material, which is available to authorized users. * Pablo D. González [email protected] Extended author information available on the last page of the article
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