Geology and conceptual model of the Domuyo geothermal area, northern Patagonia, Argentina

The western slope of Cerro Domuyo in northern Patagonia is characterized by thermal springs with boiling waters, Quaternary silicic domes, and pyroclastic deposits that suggest the existence of a geothermal reservoir. According to geochemical studies, the reservoir may have a temperature of 220 \ub0C and one of the largest advective heat fluxes reported for a continental volcanic center. In this paper, we propose a more refined conceptual model for the Domuyo geothermal area, based on a geological survey supported by U Pb, U Th, and Ar Ar geochronology and by magnetotelluric and gravity surveys. Our study indicates that the Domuyo Volcanic Complex (DVC) is a Middle Pleistocene dome complex overlying middle Miocene to Pliocene volcanic sequences, which in turn cover: 1) the Jurassic-Early Cretaceous Neuqu\ue9n marine sedimentary succession, 2) silicic ignimbrites dated at ~186.7 Ma, and 3) the Paleozoic metamorphic basement intruded by ~288 Ma granite bodies. The volcanic cycle in the DVC is distinctly bimodal, characterized by the emplacement of massive silicic domes and less voluminous olivine basalts on its southern slope. A major collapse of the central dome at ~600 ka produced a voluminous (19.4 km 3 and 133 km 2 ) block-and-ash flow, and associated pyroclastic flows, that filled a valley to the southwest at distances up to ~30 km from Cerro Domuyo summit. This was followed by a period of intense effusive activity that formed the Cerro Guitarra, Cerro Las Pampas, Cerro Domo, and Cerro Covunco silicic domes. The last two domes are the youngest and largest edifices, dated at 0.50 Ma (Ar Ar age) and 0.25 Ma (U Th age). Pre-Cenozoic successions were affected by N-S reverse and thrust faults that were later displaced by an ENE-WSW-trending transtensional belt. The basement rocks at the northern termination of the Cordillera del Viento anticlinorium were also displaced towards the east-northeast by this belt, which is observed NNW of Cerro Domuyo. The DVC was emplaced within this zone of crustal weakness. The integration of geologic observations with magnetotelluric and gravity data, allowed us to develop an updated conceptual model of the geothermal system. The geothermal reservoir is inferred at a depth of less than 2 km within pre-Pliocene fractured rocks, bounded by ~WSW-ENE trending faults and sealed by the pyroclastic deposits and rhyolitic lavas of the DVC. The location of most thermal springs is not directly controlled by faults. Instead, flows emerge at the contact between the fractured and faulted basement and the caprock

Cenozoic magmatism and extension in western Mexico: Linking the Sierra Madre Occidental Silicic Large Igneous Province and the Comondú Group with the Gulf of California rift

Emerging over the past decade has been a new view on the genesis of, and links between, the Sierra Madre Occidental silicic large igneous province, the Comondú Group of Baja California and the Gulf of California rift. Underpinning this has been a wealth of new data from both margins of the Gulf of California including offshore sampling, and marine geophysical data, in part seeded by the NSF Margins program where the Gulf of California was a principal focus site. Previously, the Sierra Madre Occidental silicic large igneous province and Comondú Group had been widely regarded as supra - subduction volcanism with the Comondú Group in particular, defining the location of the early to mid - Miocene supra - subduction zone volcanic arc, and therefore acting as both a spatial and temporal barrier to when rifting of the Gulf of California could begin. More broadly, this continental magmatism occurring during the last phase of subduction of the Farallon Plate between the Late Eocene and the Middle Miocene, shows little to n o petrogenetic connection to the active plate boundary and is more strongly linked to the progressive thinning of the upper plate and establishment of a shallow asthenospheric mantle beneath western Mexico. A database developed for this study of 4255 ages and chemical analyses for igneous rocks from 100 to 5 Ma from across western Mexico, reveals a significant transition period between 50 and 40 Ma where relatively low - volume magmatism was established across a broad area up to 800 km wide and extended up to 1000 km in board of the paleotrench. Since 40 Ma, magma fluxes greatly increased across this broad belt and compositions were initially silicic - dominated but quickly became bimodal by ~30 Ma. The space - time pattern of crustal extension is constrained in 39 areas, for which the approximate age of extension can be established on the basis of geologic relations or thermochronology. The onset of continental extension is constrained to the Eocene when extensional basins developed across the Central Plateau and the easternmost part of the Sierra Madre Occidental, approximately 500 km in board of the paleo - plate boundary. By the end of Oligocene, crustal extension had affected a wide region (250 km width) from the eastern Sierra Madre Occidental to the site of the future Gulf of California (wide rift mode). Concomitant with this extension was:\ud \ud 1) a widespread invasion of the mid to upper crust by mafic magmas with lithospheric signatures (the southern cordillera orogenic basaltic andesite suite or SCORBA), and lesser erupted volumes of uncontaminated asthenosphere - derived within - plate lavas, and;\ud \ud 2) crustal melting producing voluminous pulses of silicic ignimbrite eruptions (the SMO SLIP) with a ferroan (dry) and transitional within - plate signature. At ~19 Ma, ortho gonal extension became focused between the western side of the SMO and eastern Baja California in a ~80 - 100 km wide belt

3er. Coloquio: Fortalecimiento de los Colectivos de Docencia

Las memorias del 3er. Coloquio de Fortalecimiento de Colectivos de Docencia deben ser entendidas como un esfuerzo colectivo de la comunidad de académicos de la División de Ciencias y Artes para el Diseño, en medio de la pandemia COVID-19, con el fin de: • Analizar y proponer acciones concretas que promuevan el mejoramiento de la calidad docente en la División. • Proponer acciones que permitan continuar fortaleciendo los cursos con modalidad a distancia (remotos). • Ante un escenario que probablemente demandará en el mediano plazo, transitar del modelo remoto a un modelo híbrido, proponer acciones a considerar para la transición de los cursos. • Planear y preparar cursos de nivelación de conocimientos, para cuando se transite a la impartición de la docencia de manera mixta o presencial, dirigidos a los alumnos que no hayan tenido oportunidad de desarrollar actividades relevantes para su formación, como prácticas de talleres y laboratorios, visitas, o alguna otra actividad relevante