Repositorio Digital Sernageomin
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Reporte de visita técnica: deslizamientos de suelo en el cerro Cournou, Talcahuano, región del BioBío
No full textRevisor: Alejandro Alfaro10 p
Reporte de visita técnica por amenaza de caída de rocas en el cerro La Ballena, Puente Alto, región Metropolitana
No full textRevisor: Carolina Jara14 p
Pliocene-Pleistocene ash-fall tuff deposits in the intermountain Humahuaca and Casa Grande basins, northwestern Argentina : Tracers in chronostratigraphic reconstructions and key to identify their volcanic sources
No full textAsh-fall tuffs of the Pliocene-Pleistocene deposits of Humahuaca and Casa Grande intermountain basins, northwestern Argentina, have been differentiated into two groups based on new geochemical and geochronological data which correspond to the tuffs of the Pliocene-Lower Pleistocene alluvial fan deposits dominated by debris flow, deep sandy gravel braided, and shallow ephemeral lake deposits (Uquia and Mal Paso formations), and those recorded in Pleistocene alluvial fans sheet flood deposits. The two clusters of ages recognized: 4.3 to 2.6 Ma, and 2.2-pre 0.8 Ma, corresponding to these tuff groups, are in agreement with pulses of ignimbrite eruptions in the Altiplano Puna Volcanic Complex (APVC), and Southerm Puna calderas located west of the study region. The ash-fall tuffs of both groups are mainly vitreous to phenocryst-poor of rhyodacite-dacite composition with minor andesites to trachyandesites, characterized by 58-69% SiO2 contents, A/CNK 1-1.4, FeO/MgO (0.8-2.8), which plot in the calc-alkaline range. They can be differentiated based on its immobile trace elements ratios as indicated by a slight enrichment in LREE, higher arc affiliation and somewhat higher Sm/Yb ratios in the case of the younger group, although in both Sm/Yb ratios are indicative of sequestration of HREE in residual hornblende. The new geochemical and geochronological data of those ash fall tuffs point to these as chrono-stratigraphic tracers of the Humahuaca and Casa Grande intermountain basins stratigraphy, during the Pliocene-Pleistocene, also as the key to identify their volcanic sources.pp.208-23
Evaluación de peligro de remoción en masa en gruta de Lourdes, localidad de Mehuín, comuna de Mariquina, región de Los Ríos
No full textRevisor: Carlos Johnson N. ; Informe Técnico16 p
Evaluación de peligro de remoción en masa en un sector de la Reserva Nacional Mocho Choshuenco, comuna de Los Lagos, región de Los Ríos
No full textInforme Técnico -- Unidad Ejecutora: Dirección Regional de Los Ríos10 p
(U-Th)/He ages of Proterozoic-Paleozoic basement rocks from northern Chile (18-19° S) and implications on the Neogene uplift history of the Western Cordillera
No full textIn the Western Cordillera of northern Chile, the Proterozoic-Paleozoic Belén Metamorphic Complex is covered by late Oligocene-early Miocene (25-18 Ma) rocks, and both units are involved in west-vergent contractional deformation, which results in exhumation. A Miocene age (18 to 6 Ma) for deformation has been previously constrained by stratigraphy and cross-cutting relationships. To understand the youngest exhumation event and reverse faulting, we obtained 21 (U-Th)/He ages from two samples of the metamorphic rocks and the associate inverse thermal modeling. Five zircon (U-Th)/He ages from one sample are 113 to 226 Ma, very scattered, while five zircon ages from the other, are 20 to 49 Ma. The high dispersion of zircon (U-Th)/He data prevents the geological interpretation of results. Apatite grains from both samples yielded 11 (U-Th)/He ages between 10.4 and 18.7 Ma, with 9 values from 12.0 to 15.5 Ma. A slight positive correlation between apatite single-grain dates and effective uranium for 4 crystals of one samplesuggests relatively slow cooling. The T-t model including these 4 apatite ages shows continuous cooling from 15 to 0 Ma with a relatively more marked cooling period at 11-7 Ma. The middle-late Miocene thermal signal agrees with the geologic evolution of the region and would permit to date the last activity of the Chapiquiña-Belén reverse fault, whichuplifted and exhumed the metamorphic rocks. This signal is relatively similar to that the eastern Altiplano, but differs considerably from that the forearc.pp.313-32
Evaluación geológica de puntos de encuentro transitorio en las comunas de Curacautín y Lonquimay en caso de erupción del Complejo Volcánico Lonquimay, región de La Araucanía
No full textRevisores: Rodrigo Órdenes G. y Virginia Toloza T. ; Informe Técnico59 p
Reporte de visita técnica : Sector Morro de Arica, comuna de Arica, región de Arica y Parinacota
No full textInforme Técnico -- Unidad Ejecutora: Unidad de Peligros Geológicos y Ordenamiento Territorial, Santiago6 p
Evaluación hidrogeológica preliminar del sector de Chaitén Viejo, Provincia de Palena, Región de Los Lagos
No full textInforme Técnico INF-Los Lagos-07, 2022 -- Unidad Ejecutora: Oficina Técnica Puerto Varas, Puerto Varas13 p
Visita Técnica por deslizamiento en península de Lutrín, Comuna de Lota, Región del Biobío
Get PDFRevisor: Carolina Jara ; Informe Técnico16 p