A compressive system overimposed to an oblique rift: Applications in the Malargüe fold and thrust belt, southern Mendoza

Se llevaron a cabo modelos análogos para simular la evolución resultante de la aplicación de esfuerzos compresivos oblicuos al eje de un sistema extensional preexistente. Se utilizaron materiales granulares para representar rocas frágiles de la corteza superior. En la base de los modelos se indujo la formación de dos hemigrábenes asimétricos y de una falla de transferencia entre ambos, para luego comprimir el sistema desplazando un pistón en sentido oblicuo al rumbo de los hemigrábenes. El objetivo de estos experimentos fue analizar el arreglo estructural resultante a partir de un cambio de régimen tectónico, estudiando la influencia que ejercen las estructuras extensionales preexistentes sobre el estilo de la deformación compresiva sobreimpuesta. Aunque los resultados obtenidos muestran que la reactivación de las fallas normales es mínima, su presencia ejerce un fuerte control geométrico en el arreglo final de las fallas inversas. Al aumentar la distancia entre el sistema extensional subyacente y el frente de empuje, el control sobre los corrimientos generados se pierde. Asociados al control estructural impuesto se encontraron cambios de rumbo de los corrimientos, variaciones en las dimensiones de las láminas de corrimiento, levantamientos diferenciales en sectores próximos a la estructura subyacente y formación de corrimientos fuera de secuencia en sectores determinados del sistema. Estos resultados fueron comparados con la arquitectura estructural del sector sur de la faja plegada y corrida de Malargüe, sugiriendo analogías que permiten interpretar la presencia de trenes de extensión de orientación NE y NO durante el evento extensivo jurásico en esta región.Analogue modelling experiments were performed to simulate the evolution that results from the application of compressive stresses oblique to the axis of a pre-existing extensional system. Granular materials were used to represent brittle upper crustal rocks. Two asymmetric halfgrabens linked by a transfer fault were created in the base of the models, and were subsequently compressed moving a piston in oblique sense to the halfgrabens' strike. The aim of these experiments was to analyze the structural pattern that results from a change of tectonic regime, studying the influence that exerts the preexisting extensional structures over the style of latter compressive deformation. Even though the obtained results show limited reactivation of normal faults, the final geometric arrangement of the new reverse faults was strongly controlled by them. Increasing the distance between the underlying extensional system and the advancing thrust front results in a loss of its influence over the newly formed thrusts. Associated with the imposed structural control, strike changes of the thrusts, length variations of the thrust sheets, differential uplifting near the basal structure and out of sequence thrusting localized in certain sectors of the system were found. These results have been compared with the structural architecture of the southern sector of the Malargüe fold and thrust belt, suggesting analogies that allow interpreting the presence of NE and NW oriented extensional trends for the Jurassic extensional event in this regionFil: Yagupsky, Daniel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Cristallini, Ernesto Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Zamora Valcarce, Gonzalo. Repsol YPF; ArgentinaFil: Varadé, Roberto. Repsol YPF; Argentin

Geothermal Potential of Madrid Basin from Integrated Geophysical and Well Data Analysis (Central Spain)

New energy demand linked to world population growth and awareness about climate change have brought out the need to develop new forms of energy guided by the urgency of an ecological transition. In this context geothermal resources have the potential of contributing significantly to sustainable use in many parts of the world. In Spain, during the 80´s, oil and gas explorations carried out in the Madrid Basin confirmed the existence of two geothermal reservoirs. Here we present diverse geological features of the basin essential in geothermal exploration. We use airborne radiogenic and magnetic data to characterize the basement. Detailed ground concentration estimates of the heat producing elements are used to calculate the heat production and heat flow in the near surface. The distribution pattern of both parameters is heterogeneous with two main areas separated by southward prolongation of the Berzosa Fault. The eastern sector is characterized by both low heat production and heat flow rates while the western area is distinguished by high values as a response of the exposed granites. In addition, we build one 3D geological model and one 3D isothermal model with Leapfrog Geothermal from seismic, well data and mapping information

Sitios de Interés Geológico de la República Argentina

Fil: Folguera, Andrés. Laboratorio de Tectónica Andina, Departamento de Geología, Universidad de Buenos Aires; Argentina.Fil: Zamora Valcarce, Gonzalo. Repsol-YPF; Argentina.Fil: Miranda, Fernando. Ministerio de Planificación Federal, Inversión Pública y Servicios. Secretaría de Minería. Servicio Geológico Minero Argentino (SEGEMAR); Argentina.Fil: Leanza, Héctor. Ministerio de Planificación Federal, Inversión Pública y Servicios. Secretaría de Minería. Servicio Geológico Minero Argentino (SEGEMAR) y CONICET; Argentina.El volcán Tromen, en la región norte de la provincia del Neuquén, constituye uno de los aspectos más sobresalientes de una comarca que en tiempos geológicos recientes se vio afectada por una intensa actividad volcánica. El imponente Tromen, con sus llamativos derrames de lava y escoriales, junto a otros volcanes menores en el área, permiten al visitante apreciar una fotografía instantánea de la magnitud de estos eventos efusivos, algunos de los cuales tuvieron lugar en tiempos históricos. Si bien estos volcanes emitieron sus lavas en forma casi contemporánea con respecto a aquellos ubicados a más de cien kilómetros al oeste y que forman parte de la cadena de volcanes activos de la cordillera de los Andes en la zona limítrofe argentino-chilena, su desarrollo y emplazamiento responden a un fenómeno diferente

El Volcán Tromen. Ríos de lava

El volcán Tromen, en la región norte de la provincia del Neuquén. constituye uno de los aspectos más sobresalientes de una comarca que en tiempos geológicos recientes se vio afectada por una intensa actividad volcánica. El imponente Tromen. con sus llamativos derrames de lava y escoriales. junto a otros volcanes menores en el área. permiten al visitante apreciar una fotografía instantánea de la magnitud de estos eventos efusivos, algunos de los cuales tuvieron lugar en tiempos históricos. Si bien estos volcanes emitieron sus lavas en forma casi contemporánea con respecto a aquellos ubicados a más de cien kilómetros al oeste y que forman parte de la cadena de volcanes activos de la cordillera de los Andes en la zona limítrofe argentino-chilena. su desarrollo y emplazamiento responden a un fenómeno diferente.Tromen volcano, in northern Neuquén Province, constitutes one of the most dominant structures in an area that, in recent geological times, was affected by an intense volcanic activity. The imposing Tromen edifice with its striking lava flows and scoriae, together with other minor volcanoes, allow the visitor the chance to appreciate a snapshot of the magnitude of these effusive events, some of which even occurred during historical times. Even though these volcanoes emitted their lavas almost simultaneously with those located more than one hundred kilometers westward in the Andean Cordillera, along the Argentinean and Chilean border line, their development and emplacement were responses to different conditions.Fil: Folguera, Andrés. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología. Laboratorio de Tectónica Andina; ArgentinaFil: Zamora Valcarce, Gonzalo. Repsol - YPF; ArgentinaFil: Miranda, Fernando. Secretaria de Industria y Mineria. Servicio Geológico Minero Argentino. Instituto de Geología y Recursos Minerales; ArgentinaFil: Leanza, Hector Armando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Field trip guide: Andean Cordillera and backarc of the south-central Andes (~38.5°S to 37°S)

The Andes of the Neuquén Mesozoic basin have experienced multiple episodic tectonic events as a consequence of the changes of the plate tectonic boundary configuration. Each episode of deformation has overprinted the previous one, making it difficult to unravel the Andean tectonic history. The first deformation event took place in the uppermost Cretaceous with the formation of the Agrio fold-and-thrust belt. This event was related to the shallowing of the subducting plate recorded by the migrationof the volcanic arc toward the foreland. During the late Oligocene-early Miocene, an extensional event, related to the steepening of the subducted plate, affected only the hinterland region causing the opening of the Cura Mallín basin. This basin was closed during the late Miocene, together with the development of a new fold-and-thrust belt that reactivated the previous structures. During the Late Tertiary, two more episodes of extension and compression affected the Andean area. The trip focuses on the field evidence that documents this complex history of evolution by looking at evidence ofthe sequence of the distinct tectonic events.Fil: Zapata, Tomás. Repsol YPF; ArgentinaFil: Zamora Valcarce, Gonzalo. Repsol YPF; ArgentinaFil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Yagupsky, Daniel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Oblique half-graben inversion of the Mesozoic Neuquén Rift in the Malargüe Fold and Thrust Belt, Mendoza, Argentina: New insights from analogue models

The Malargüe fold and thrust belt, located in the Andean mountains between 34°S and 36°30′S, formed in response to contraction during Cenozoic times. Its structural style and geometry was controlled by the Mesozoic rift system that formed the Neuquén basin in west-central Argentina. The rift architecture in the southern sector of this belt was previously interpreted in terms of the present N-S compressive structural trends, assuming the inversion of pre-existing normal faults with the same orientation. Here, we propose that the NW-SE-trending El Manzano-Liu Cullín lineament, located in the northern termination of the Sierra Azul, reflects the presence of a half-graben master fault in the subsurface. This hypothesis is supported by subsurface data, a balanced cross section, and it is tested using a series of scaled sandbox analogue models. We suggest that the lineament responds to a reactivated NW-trending half-graben fault, hidden by the mainly N-S-trending Andean structures. The proposed orientation is in agreement with the NE-SW extension developed in the Neuquén basin during the Triassic-Early Jurassic. The modeling of the inverted oblique half-graben reveals that the strikes of the main structures of inversion-related belts may often be independent of the orientation of the previously developed extensional system, providing a new perspective for their interpretation.Fil: Yagupsky, Daniel Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Cristallini, Ernesto Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Fantín, Julián. Repsol YPF S.A; ArgentinaFil: Valcarce, Gonzalo Zamora. Repsol YPF S.A.; ArgentinaFil: Bottesi, Germán. Repsol YPF; ArgentinaFil: Varadé, Roberto. Repsol YPF; Argentin

The Transitional Zone Between the Southern Central and Northern Patagonian Andes (36–39°S)

The transition zone from the Southern Central to the North PatagonianAndes is characterized by a low topography and low shortenings. During its evolution,an extensional event in late Oligocene times affected the western section ofthe Late Cretaceous to Eocene fold and thrust belt. Late early Miocene contractionthen constructed most of the eastern Andean slope as in sequence structures stackedin the frontal sector of the fold and thrust belt. However, out of sequence structuresderived mainly from the inversion of the late Oligocene extensional depocentersuplifted the axial Andean zone at these latitudes. Contractional and extensionalstages coincide with periods in which the arc expanded and retracted, respectively.Shortening gradients from 30 km in the north to only 11 km in the south anddevelopment of synorogenic depocenters are linked to arc dynamics.Fil: Rojas Vera, Emilio Agustin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Orts, Darío Leandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Folguera Telichevsky, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Zamora Valcarce, Gonzalo. No especifíca;Fil: Bottesi, Germán. YPF - Tecnología; ArgentinaFil: Fennell, Lucas Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Chiachiarelli, Francisco. YPF - Tecnología; ArgentinaFil: Ramos, Victor Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentin

Middle Jurassic-Late Cretaceous Paleogeography of the Western Margin of the Neuquén Basin (34° 30′–36° S)

U–Pb dating of detrital and igneous zircons from the retroarc deposits of the Neuquén Basin has shed light over the Mesozoic evolution of the western border of South America, yet the coeval arc and forearc regions remain mostly indirectly characterized. Furthermore, recent paleogeographic reconstructions consider the arc and forearc regions as a tectonically stable and static region at least until Late Cretaceous. In this chapter, we aim to contribute to the Middle Jurassic-Late Cretaceous paleogeographic reconstructions of the western margin of South America from a western point of view integrating the coeval arc and forearc evolution, between 34° 30′ and 36° S. We focus here in the deposits exposed along the Chilean slope of the Principal Cordillera and use four new detrital zircon age data to determine their ages and main source areas. These ages are compared with 38 published U–Pb detrital zircon ages and integrated into a series of paleogeographic cross sections which illustrate the Mesozoic evolution along the Southern Central Andes encompassing the forearc, arc, and retroarc regions. Our data show that the arc and forearc regions were active at least since the Middle Jurassic. Evidence for this tectonic activity corresponds to the development of forearc basins in the Middle Jurassic and Early Cretaceous times. New ages along the Chilean slope of the Andes allow suggesting an early beginning for the compressive period during the latest Early Cretaceous. The formation of a geographic barrier, as a consequence of the compressive regime, would explain the differences in the sediments provenance between western and eastern deposits during the latest Late Cretaceous. Finally, the almost complete record of Mesozoic ages in the detrital and volcanic deposits of the western slope of the Southern Central Andes constitutes a counter-argument about the null or waning activity proposed for the Middle Jurassic or Late Cretaceous from U–Pb detrital zircon analysis of the eastern Mesozoic deposits. Conversely, our data indicate a continued activity of the arc-related volcanism and magmatism throughout all the Mesozoic time.Fil: Tapia Silva, Felipe Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Muñoz, Marcia. Universidad Andrés Bello; ChileFil: Farías, Marcelo. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Departamento de Geología; ChileFil: Charrier, Reynaldo. Universidad Andrés Bello; ChileFil: Astaburuaga, Daniela. Universidad de Chile. Facultad de Ciencias Físicas y Matemáticas. Departamento de Geología; Chil