Revista de la Asociación Geológica Argentina https://revista.geologica.org.ar/raga <p>The <strong>Revista de la Asociación Geológica Argentina</strong> publishes original articles on geological topics, especially those related to Argentina and South America.</p> <p> </p> <p>The journal is published quarterly by the <a href="http://www.geologica.org.ar/">Asociación Geológica Argentina</a>. The AGA was created in Buenos Aires on June 30, 1945, in the Geology classroom of the Facultad de Ciencias Exactas, Física y Naturales of the Universidad de Buenos Aires with the initial name of Sociedad Geológica Argentina. Among the purposes of the Society figured as one of its main objectives to publish the Revista de la Sociedad Geológica Argentina. The <a href="https://revista.geologica.org.ar/raga/issue/view/4">first issue</a> was published in January 1946 under the direction of Dr. Armando F. Leanza and Dr. Carlos D. Storni.</p> <p>The original purpose of the journal was to disseminate the scientific work of the members of the sociación Geológica Argentina, but it quickly became a reference publication for all subdisciplines of geological sciences in Argentina and other South American countries.</p> <p>Our journal was incorporated into the Núcleo Básico de Revistas Científicas y Tecnológicas Argentinas of CONICET, which brings together all the scientific and technological publications published in the country that have the highest editorial and content quality, RAGA was selected to participate in the Portal de Publicaciones Científicas y Técnicas, an open access platform to manage your work online. In 2010 the editorial treatment ceased to be by post mail, to move to a modern digital treatment system. This great step implied the definitive transition to an open system and adherence to the Creative Commons license, which allows the public dissemination of scientific works with proof of authorship and permission for public reproduction and distribution.</p> <p>Starting 2020, we have decided to continue in this direction, generating an OJS editorial management platform through our own website, with the support of the PREBI-SEDICI of the Universidad Nacional de La Plata. This new platform, with a modern and versatile character, will allow a much more fluid handling of manuscripts and better communication between authors and editors.</p> <p> </p> Asociación Geológica Argentina. en-US Revista de la Asociación Geológica Argentina 0004-4822 <h3>Nota de copyright</h3> <p>Los autores conservan los derechos de autor y garantizan a la revista el derecho de ser la primera publicación del trabajo licenciado según una licencia de atribución <a href="http://creativecommons.org/licenses/by/3.0/" target="_new">Creative Commons</a> que permite a otros compartir el trabajo con el reconocimiento de la autoría y de la publicación en la que se publicó por primera vez.</p> <h3>Declaración de privacidad</h3> <p>Los nombres y direcciones de correo electrónico introducidos en esta revista se usarán exclusivamente para los fines declarados por esta revista y no estarán disponibles para ningún otro propósito u otra persona.</p> Nora M. Sabattini (1941-2021) https://revista.geologica.org.ar/raga/article/view/1657 Alberto C. Riccardi Copyright (c) 2022 Alberto C. Riccardi https://creativecommons.org/licenses/by-nc/4.0 2022-08-25 2022-08-25 79 4 659 664 Buenos Aires dunes reservations in relation to the sea level reversal https://revista.geologica.org.ar/raga/article/view/1603 <p>Buenos Aires coastal barriers originated by the Holocene fluctuation of the sea level. The fine sand abundance and the onshore winds constructed the Eastern Barrier while at the south dunes climbed to old cliffs. The increase in Precipitation and the afforestation transformed sand dune fields into resort villages, and later to cities devoted to the “sun and beach” tourism. Notwithstanding that, hydrogeologic water reserves always limited some localities. The urban sprawl led to implement urban cities that were limited to the widths of these barriers. Dune forestation led to beach unbalances, that increased triggered by extratropical storms arriving from the southeast. Sand mining from the beaches was forbidden (law 8758/77). Urban growth caused the proposal of buffer areas (statement 8912/77) and to promote reserves to compensate the urban expansion along the coast (statement 3202/06). During the eighties and nineties some coastal counties promote foredune fixation with fences (locally called “<em>enquinchados”)</em> constructed by branches, but without a proper sand management. Today, foredune retreat is 1 m/year averaged, although at some counties it could be higher caused by some activities (stormwater patterns, coastal defences, bathing facilities). Considering the present forecasts of a higher sea level (0.4-0.8 m for year 2100) and the increase in the frequency and intensity of extratropical storms, it is clear that these dune problems would be worse. In this sense, new initiatives and management policies should be planned.</p> Federico Isla Pedro Garzo Luis Camilo Cortizo Copyright (c) 2022 Federico Isla, Pedro Garzo, Luis Camilo Cortizo https://creativecommons.org/licenses/by-nc/4.0 2022-05-25 2022-05-25 79 4 586 599 Hydrodynamics, hydrochemistry and occurrence of uranium in the Ituzaingó and Salto Chico Aquifers, Entre Ríos Province https://revista.geologica.org.ar/raga/article/view/1621 <p>Ituzaingó, Salto Chico and Ubajay Aquifers are the most important hydrogeological units in the Chaco-paranaense region because they are among the most productive, provide high quality fresh water and supply agriculture, industry and human consumption. From the hydrodynamic analysis at piezometric level, a network of groundwater flow was defined ―the groundwater divide―. The hydraulic head does not exceed 60 masl; therefore, potential fluvial recharge processes may be proposed with more extensive and deeper groundwater flows. This would increase the water-rock contact time, which would impact on salinity. A large extension of the Aquifer region has groundwater showing a salinity level lower than 2000 mg/l, even in the western areas, where the Salto Chico and Ubajay Aquifers rarely exceed 1000 mg/l. There sodium bicarbonate facies predominate; followed by the calcium bicarbonate facies, which are almost at the same level as the sodium chloride-sulfate ones. From a regional perspective, the average value of nitrates is close to 10 mg/l; there is a low concentration of arsenic (0.1 - 0.2 mg/l) and iron (0.2 - 0.4 mg/l), which are only present punctually. Uranium has been detected as a trace, showing a regional distribution and average values of 25 μg/l (3 μg/l minimum and 101μg/l maximum), so it can be considered almost a minority species. The positive and significant correlations of uranium with other components are TDS (0.62), SO42- (0.61) and Na+ (0.64). They coincide in their regional distribution ―center-north of the province of Entre Rios― in a clear association of hydrodynamic and hydrochemical processes.</p> Adrian Silva Busso Gabriela Rouiller Copyright (c) 2022 Adrian Silva Busso, Gabriela Rouiller https://creativecommons.org/licenses/by-nc/4.0 2022-08-25 2022-08-25 79 4 600 624 Characterization and structural evolution of the Auca Mahuida volcanic field, Neuquén. https://revista.geologica.org.ar/raga/article/view/1617 <p>By means of the analysis of topographic data and volcanic rock thicknesses, it was possible to prove that the Auca Mahuida volcanic field lies on a domed structure of similar diameter. The absence of the Malargüe Group (Campanian-Danian) below most of this massif, along with the presence of an erosive angular unconformity which separates the Cretaceous layers of the Neuquén Group from the Quaternary volcanic rocks, are a sign that this dome was raised and partially eroded before the Pleistocene volcanic activity. It is probable that this structure is due to a thermal uplift caused by the emplacement of magma chambers in depth and shallower igneous intrusive bodies during the Pliocene-Pleistocene. Furthermore, the presence of a slight regional slope towards the east-northeast was recognized in the study area, which explains the exiguous topographic asymmetry of the Auca Mahuida shield volcano and the larger spread of the basaltic flows on its eastern flank.</p> Alejandro Basaldúa Ernesto Cristallini Copyright (c) 2022 Alejandro Basaldúa, Ernesto Cristallini https://creativecommons.org/licenses/by-nc/4.0 2022-08-25 2022-08-25 79 4 625 641 Multiple tectonic reactivations of the Cachi fault system at the eastern edge of the southern Luracatao valley, Calchaquíes valleys, northwestern Argentina https://revista.geologica.org.ar/raga/article/view/1614 <p>The Luracatao valley (boundary between Calchaquí valleys and Puna) is flanked to the east by sierra de Cachi and cumbres de la Laguna mountain ranges, delimited by first-order structures called here as Cachi fault system, from east to west: eastern fault, central fault and western fault. These faults have N-S orientation dipping to the east. The eastern main fault corresponds to a normal cretaceous fault that bounded the Brealito-Molinos half-graben to the west. Central and western faults, interpreted as splays of the eastern fault, would have originated as cretaceous normal faults with multiple tectonic inversion-reactivation processes during the Andean orogeny. The basement heterogeneities have controlled the location of new structures during the Mesozoic and Cenozoic, through strong parallelism between the basement foliations and faults. In this study, we present new field data that help us to reconstruct this structures system evolution, which has been described in previous works as a unique master fault (Cachi fault) with a localized splay, and these document multiple reactivation stages from Eocene.</p> Carolina Montero Fernando Hongn Alejandro Aramayo Copyright (c) 2022 Carolina Montero, Fernando Hongn, Alejandro Aramayo https://creativecommons.org/licenses/by-nc/4.0 2022-07-22 2022-07-22 79 4 642 658 Structural evolution of the Quebrada del Toro Basin: Influence of pre-cretaceous structures on the Andean fold-and-thrust belt in the Argentinian Eastern Cordillera https://revista.geologica.org.ar/raga/article/view/1636 <p>The superimposition of the tectonic events recorded in the Argentinian Eastern Cordillera conditioned the current structural style. In the Quebrada del Toro Basin (Salta province), coinciding with the central section of the Calama-Olacapato-Toro lineament (COT), pre-cretaceous structures are recognized that would have favored the development of inverse structures during Andean tectonics. We present new structural, stratigraphic and sedimentological data which allowed an integral analysis through the generation of balanced geological sections, deformation restorations and 2D forward modeling. At least two deformation events were identified: the first, during the upper Tremadocian, corresponds to the Tumbaya extensional phase expressed through two NNW-SSE striking and ENE dipping normal synsedimentary faults (de la Cruz and Pascha). The second deformation event, of compressive nature, would have begun during the middle Eocene, with the generation of large-scale folds related to relatively shallow Gólgota thrust and their subsequent transport by two high angle reverse faults (Gólgota and Lampazar) with deeper detachment. In this sense, Paleozoic structures controlled the location and western vergence of the Gólgota thrust in the study area, a caracteristic that reinforces the hypothesis about the preponderant influence of Ordovician normal faults on western vergence thrusts.</p> Carla Agustina Villagran Raúl Eudocio Seggiaro Rubén Eduardo Filipovich Facundo Domingo Apaza Emilio Barrabino Melina Celedón Copyright (c) 2022 Carla Agustina Villagran, Raúl Eudocio Seggiaro, Rubén Eduardo Filipovich, Facundo Domingo Apaza, Emilio Barrabino, Melina Celedón https://creativecommons.org/licenses/by-nc/4.0 2022-11-28 2022-11-28 79 4 659 679