Relocation of hypocenters from DOMERAPI and BMKG networks: a preliminary result from DOMERAPI project

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Pliocene to Quaternary Retroarc Extension in the Neuquén Basin: Geophysical Characterization of the Loncopué Trough

The Loncopué Trough is an extensional basin produced by the extensional reactivation of the hinterland area of the Southern Central Andes. Neotectonic extensional structures in this basin bound a broad topographic low filled with volcanic and volcaniclastic rocks. The studies carried out in the area of the Loncopué Trough have concentrated on the study of its neotectonic activity, volcano-sedimentary infill and the surface structure. Less effort has been paid to characterize the magnetic properties of the crust and to unravel the deep geometry of this Pliocene to Quaternary extensional setting. Therefore, magnetic and gravimetric data were used to highlight the boundaries of the magnetic sources and to obtain a crustal-scale 2D density model at 38°S. To complement this work, an effective susceptibility model using the Magnetization Vector Inversion method was estimated, which takes into account the combined effects of remanence and induced magnetization. Additionally, the Curie depth points were calculated through the spectral analysis technique in order to determine the thermal structure of the retroarc area. From this analysis, we were able to characterize the main structures associated with this extensional trough. Based on this analysis, only the Loncopué eastern fault system is considered as having a crustal-scale hierarchy. Additionally, the susceptibility model revealed possible fluid (magmatic and or hydrothermal) reservoirs in the area of the Copahue volcano and the Codihue and Cajón de Almanza depocenters/volcanic fields. These spots coincide with shallower values of the calculated Curie depth point, implying higher heat flows. Finally, the 2D density model shows an area of lower crustal attenuation that is coincident with one of the described potential magmatic/hydrothermal reservoirs and is decoupled from the upper crust extensional structures immediately to the west in the Loncopué Trough. This crustal configuration could be explained by a simple shear deformation model with a crustal-scale master fault dipping to the east.Fil: Pesce, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Gianni, Guido Martin. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Gimenez, Mario Ernesto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; 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"; Argentin

Quaternary Deformation in the Neuquén Basin, Explained by the Interaction Between Mantle Dynamics and Tectonics

Quaternary deformations described in the retro-arc region at the latitudes of the Neuquén Basin can be divided into two main groups: a northern group characterized by Quaternary deformation zones concentrated near the main topographic breaks of different morphostructural systems, and a second group located in the southern Neuquén Basin distinguished by disconnected, sparced and noncontinuous Quaternary deformational zones. In the northern Neuquén Basin, evidence of active deformation is associated with the Frontal Cordillera (33°?34° S); while in the foreland area, young deformations concentrate in the San Rafael Block. In the southern Neuquén Basin, a western deformational belt constitutes the continuation to the north of an intra-arc fault system associated with dip- and strike-slip displacements in a strain-partitioned regime (Liquiñe?Ofqui fault system). At these latitudes, to the east, isolated evidence of Quaternary deformation, regional uplift and development of non-equilibrated fluvial profiles are recognized in the Tromen and Auca Mahuida volcanic plateaux and sierra de Cara Cura-sierra de Reyes area. These systems are short and unconnected and have been explained through an intricate pattern of asthenospheric anomalies evidenced from magnetotelluric data. These mantle anomalies could be related to the tearing of the subducted Nazca plate at depth evidenced by seismic-tomographic data. We therefore suggest that the thermally weakened crust at the southern Neuquén Basin latitudes could be the main control responsible for focalizing contractional, extensional and transpressional deformations in isolated mountain systems.Fil: Sagripanti, Lucía. 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: Colavitto, Bruno. 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: Astort, Ana. 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: Folguera, Andrés. 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

Plume Subduction Beneath the Neuquén Basin and the Last Mountain Building Stage of the Southern Central Andes

The occurrence of a Neogene shallow subduction stage, as well as, a Pliocene slab-tearing, and steepening of the Nazca plate in the southern Central Andes are well established. However, a satisfactory explanation for the origin and connection between these complex processes is still elusive. In this contribution, we revise the late Cenozoic tectonic and magmatic evolution of the southern Central Andes between 35° and 38° S and discuss different proposals for the Miocene slab shallowing and its Pliocene destabilization. Recent plate kinematic reconstructions show that Neogene arc-front expansion linked to slab shallowing, fold belt reactivation in the main cordillera and intraplate contraction in the San Rafael Block correlates with the subduction of the ancient Payenia plume, a deep mantle anomaly potentially rooted in the lower mantle. Also, the Nazca slab tear determined from tomographic analyses and subsequent slab steepening may also be a direct consequence of this plume subduction process. Considering the westward drift of South America and the presence of several neighbor hotspots over the Nazca plate, the Payenia plume overriding could be the first of future episodes of plume?trench interaction in the Andes.Fil: Gianni, Guido Martin. 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 Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Pesce, Agustina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: García, Luciano Héctor. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Lupari, Marianela Nadia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Correa Otto, Sebastian Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; ArgentinaFil: Nacif Suvire, Silvina Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan; Argentina. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto Geofísico Sismológico Volponi; 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"; Argentin