Emplacement and temporal constraints of the Gondwanan intrusive complexes of northern Patagonia: La Esperanza plutono-volcanic case

摘要: Abstract Two main lines of evidence disagree whether or not the Patagonian blocks collided with Gondwana. All models invoke voluminous magmatism La Esperanza Complex as for active subduction magmatic arc to a postcollisional setting. The evolution this bimodal igneous suite is reassessed field, geochronological (SHRIMP U-Pb zircon and K-Ar mica) petrophysical data. Emplacement high-K calk-alkaline granitic magmas occurred at shallow crustal levels (2–8 ± 2 km depth) related development collapse caldera associated regional NW-SE structural trend. Magmatism involved intermediate hybrid pulses 273 ± 2 Ma 255 ± 2 Ma (Prieto Granodiorite) that shifted like yo-yo acidic 260 ± 2 Ma 250 ± 2 Ma (Donosa Calvo granites). Absence solid-state deformation features low anisotropy degrees in granites indicate its fabric origin. Magnetic granodiorites displays concentrical pattern subhorizontal foliations lineations. Parallel volcanic axis, magnetic moderately plunging lineations common feeder system plutonics volcanics. Donosa Granite shows discordant WNW-ESE ENE-WSW trending foliations. plutono-volcanic construction (273–255 Ma) followed NE-SW diamond shape faults trends supracrustal discontinuities. Magmatic Climax bracketed 260 Ma. edifice evidenced by intrusion acid magma plugs dike swarms between 250 246 Ma. A similar age range was identified other areas Patagonia syn tectonic events. No activity such major uplift, metamorphism thrusting found excepting strike-slip faulting extension. Therefore, high level episode, may have structurally recorded an collision during crystallization cooling.