Evolution of the Jurassic Comallo volcanic sedimentary complex in the western North Patagonian Massif, Rio Negro province, Argentina

A multi-proxy study of the Cerro Piche Graben - A Lower Jurassic basin in the central North Patagonian Massif, Argentina

“…The extra-Andean domain includes the outcrops of Jurassic volcanic rocks in the NPM. This domain includes the Marifil Volcanic Complex in the eastern part of the NPM; and the Taquetrén (Nullo and Proserpio, 1975), Sañicó (Stipanicic et al, 1968), Garamilla (Nullo, 1978) and Lonco Trapial formations (Lesta and Ferello, 1972), the Comallo Complex (Barros et al, 2020), and the Cañadón Chileno Complex (Benedini et al, 2020) of the central and western part of the NPM. This widespread Jurassic magmatism has been linked with the Karoo mantle plume impingement, related to Gondwana break-up, the opening of the Atlantic Ocean, and westward drifting of Patagonia (Cox, 1992;Pankhurst and Rapela, 1995;Encarnación et al, 1996;Pankhurst et al, 2000;Riley and Knight, 2001;Storey et al, 2013).…”

“…In the western NPM, the Taquetrén (Nullo and Proserpio, 1975) and Garamilla (Nullo, 1978) formations and the Comallo (Barros et al, 2020) and Cañadón Chileno (Benedini et al, 2020) complexes are well exposed from the Limay river to the Sierra de Taquetrén locality (all indicated as G in Fig. 1).…”

“…The Pliensbachian Garamilla Formation (U-Pb zircon age of 189 ± 1 Ma - Benedini et al, 2014) is characterized by ignimbrites, breccias, tuffs, and lavas of mainly intermediate to rhyolitic composition, revealing a progressive change from a subduction to an intraplate-related tectonic setting (Benedini et al, 2014). The Comallo Complex has been related to a NW-SE pull-apart volcanic depocenter of Sinemurian age (U-Pb zircon age of 192 ± 3 Ma, Barros et al, 2020). Volcanic products, including pyroclastic and coherent volcanic rocks, as well as a few sedimentary deposits, characterize the lower section of the Comallo Complex.…”

“…Volcanic products, including pyroclastic and coherent volcanic rocks, as well as a few sedimentary deposits, characterize the lower section of the Comallo Complex. The upper section is dominated by red beds deposited in a fluvial sedimentary environment (Barros et al, 2020). The Cañadón Chileno Complex (Benedini et al, 2020) is a small asymmetrical volcanic and sedimentary depocenter, which has been dated to the Pliensbachian (U-Pb zircon age of 188 ± 3 Ma - Benedini et al, 2020).…”

“…The upper section is dominated by red beds deposited in a fluvial sedimentary environment (Barros et al, 2020). The Cañadón Chileno Complex (Benedini et al, 2020) is a small asymmetrical volcanic and sedimentary depocenter, which has been dated to the Pliensbachian (U-Pb zircon age of 188 ± 3 Ma - Benedini et al, 2020).…”