The closure of the Rocas Verdes Basin and early tectono-metamorphic evolution of the Magallanes Fold-and-Thrust Belt, southern Patagonian Andes (52–54°S)

Abstract

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Early rifting during marginal basin development: Petrography, microstructure, and detrital zircon U‐Pb geochronology of the Lapataia Formation, Argentine Fuegian Andes

“…The presence of late Albian inoceramids near the top of this unit establishes the youngest age constraint (Olivero & Martinioni, 1996b). This is in agreement with the Aptian‐Albian fauna found in the ‘Estratos de Tekenika’, an arc‐related equivalent of the Yahgan Formation exposed further south (Suárez et al, 1985); and with the occurrence of detrital zircons ranging from 130 to 105 Ma (U‐Pb geochronology, Barbeau, Gombosi, et al, 2009; Muller et al, 2021). The older age limit of the Yahgan Formation is unknown, although the presence of Tithonian‐Lower Cretaceous ammonoids and belemnoids suggests it may span as far as the uppermost Jurassic in some areas of the Fuegian Archipelago (Suárez et al, 1985; Winn, 1978).…”

“…Barbeau, Gombosi, et al (2009), *21. Muller et al (2021) are common not only in the TFIMC, but also in parts of eastern Antarctica-Ross orogen .…”

The low-grade basement at Península La Carmela, Chilean Patagonia: new data for unraveling the pre-Permian basin nature of the Eastern Andean Metamorphic Complex

“…1B). Thus, although the pressure values are lower than those of a typical accretionary prism (e.g., Chonos Metamorphic Complex; Willner et al 2000), the P-T conditions exhibited by the EAMC are in the range expected for regional metamorphism during back-arc basin closure (e.g., Muller et al 2021) rather than for subduction zone complexes (Ramírez-Sánchez et al 2005;Willner et al 2009). Zircon fissiontrack thermochronology records a late Permian cooling age which is related to the last stages of regional metamorphism (Thomson and Hervé 2002).…”

Palaeozoic – Early Mesozoic geological history of the Antarctic Peninsula and correlations with Patagonia: Kinematic reconstructions of the proto-Pacific margin of Gondwana

“…This basin reconstruction was modified to follow the line of ophiolitic outcrops and basin sediments of Patagonia (Calderón et al, 2016) rather than the Miocene Magallanes-Fagnano fault system (Betka et al, 2016) used by Eagles (2016) and van de Lagemaat et al (2021). Based on geological evidence, rifting of the Rocas Verdes Basin commenced during the Late Jurassic (Calderón et al, 2007;van de Lagemaat et al, 2021;Muller et al, 2021) and closed in the mid-to Late Cretaceous (Katz, 1972;Dalziel, 1981;Barbeau et al, 2009;Eagles, 2016). Global plate motions based on marine magnetic anomalies and fracture zones, combined with geological data, constrain this closure to 113-102 Ma (van de Lagemaat et al, 2021), with some workers suggesting a later closure (minimum age of ~83 Ma; Muller et al, 2021).…”

“…Based on geological evidence, rifting of the Rocas Verdes Basin commenced during the Late Jurassic (Calderón et al, 2007;van de Lagemaat et al, 2021;Muller et al, 2021) and closed in the mid-to Late Cretaceous (Katz, 1972;Dalziel, 1981;Barbeau et al, 2009;Eagles, 2016). Global plate motions based on marine magnetic anomalies and fracture zones, combined with geological data, constrain this closure to 113-102 Ma (van de Lagemaat et al, 2021), with some workers suggesting a later closure (minimum age of ~83 Ma; Muller et al, 2021). This closure is often correlated with the emergence of coarser sediments in Patagonia.…”