Repositorio Digital Sernageomin
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Visita técnica por remoción en masa en talud de calle Los Pelícanos sector Los Molinos Alto, comuna de Valdivia, región de Los Ríos
Get PDFRevisor: Carolina Jara. -- Informe Técnico -- Unidad Ejecutora: Dirección Regional de Los Ríos, Valdivia13 p
Mediciones GPR en respuesta a Asistencia Técnica en Salto del Laja, Región del Biobío
Get PDFInforme Técnico -- Unidad Ejecutora: Unidad de Geofísica del Departamento de Geología General. Santiago14 p
Evaluación de peligro de remoción en masa en seis sectores de la comuna de Galvarino y cinco sectores de la comuna de Lumaco afectados por incendios forestales, región de La Araucanía
No full textInforme Técnico -- Unidad Ejecutora: Dirección Regional de Los Ríos, Valdivia22 p
Remociones en masa : ¿Cuáles son las zonas más sensibles a sufrir estos procesos y cómo podemos minimizar sus consecuencias?
No full textCorresponde a anexo de BSNGM 16319 DVD: Zonificación de áreas expuestas a peligros de remoción en masa en la región de Los Ríos ; Xterrae Geologí
Geoquímica y mineralogía de sedimentos fluviales de la cuenca del río Limarí, región de Coquimbo, Chile
Get PDFInforme Registrado IR-23-106122 p
MANUEL RENATO REYES BIANCHI (1931-2021) Legado científico y significado de su deceso en el ámbito geológico y paleontológico nacional
No full textpp.162-16
MANUEL RENATO REYES BIANCHI (1931-2021) Legado científico y significado de su deceso en el ámbito geológico y paleontológico nacional
Get PDFpp.162-16
Evaluación geológica de puntos de encuentro transitorio en la comuna de Putre, Región de Arica y Parinacota, en caso de erupción del complejo volcánico Taapaca
No full textInforme Técnico -- Unidad Ejecutora: Unidad de Geología y Peligros de Sistemas Volcánicos, Santiago46 p
Freshwater bivalves and their environmental conditions in a Jurassic lacustrine system (Cañadón Asfalto Formation) from Patagonia, Argentina
No full textAt the moment, two freshwater bivalve species were described for the continental Jurassic of Patagonia: Diplodon simplex Morton and Diplodon matildensis Morton from La Matilde Formation of the Santa Cruz province. The Cañadón Asfalto Formation located in Chubut province exhibits a high diverse invertebrate fossil fauna preserved mainly in lacustrine facies, which includes clam shrimps, bivalves, gastropods, ostracods and insects. However, few studies have been carried out on freshwater bivalve of this geological unit. In this work, a morphological description of bivalve assemblage and paleoenvironment analysis from the Cañadón Asfalto Formation was performed. Forty samples were collected from three stratigraphic levels at the Cañadón Asfalto locality. These levels are ash fall tuffs rich in glass particles accumulated in a lacustrine system with development of microbial activity. Morphological analyzes of outline and sizes were performed at each level. Our results showing the smallest-sized association of unionids recorded for the Jurassic time with size ranging from 7.6-11.7 mm long and 5.2-7.6 mm high. The environmental influence of pyroclastic falls could have played an important role in the development of the sizes of populations and shells.pp.248-26
Compositional and geothermobarometric analysis of the Upper Miocene tholeiitic volcanic products in the northern Andes at 5-6° N latitude : The Combia Volcanic Province
No full textThe Combia Volcanic Province (~11-5 Ma), is a volcaniclastic sequence located in northwest Colombia between the Central and Western cordilleras at 5-6° N latitude. Its source is associated with the volcanic activity of the magmatic arc produced by the subduction of the Nazca plate under the South American plate in the northern Andes. The distribution, composition, and chronostratigraphy of the province’s deposits are well-known, with the volcanic sequences characterized as compositionally bimodal. The older rocks (ca. 11-9 Ma) display tholeiitic affinity, whereas the younger (ca. 9-5 Ma) are mostly calc-alkaline, with some adakite-like signature recognized. While the magmatic system for the calc-alkaline magmas has been previously extensively studied, the processes that occurred during the magma stagnation and ascent are unknown for the tholeiitic magmas. This work bridges this gap by the study of tholeiitic lava flows outcropping at the center of the province, through petrography, mineral chemistry, whole-rock analysis, and geothermobarometry calculations of the crystallization conditions. Texturally, the rocks are porphyritic with plagioclase (An50-90) and clinopyroxene (augite and pigeonite) phenocrysts and microphenocrysts, embedded in a glassy and microcrystalline groundmass. Compositionally, the rocks vary from basaltic andesite to andesite (52.8-57.8 wt% SiO2), with relative enrichments of LILE to HFSE and REE to chondrite. Crystallization conditions, based on several plagioclase-melt and pyroxene-melt geothermobarometers, were estimated at T=1,095-1,153 °C and P=0.22-0.60 GPa for the plagioclase, T=1,046-1,131 °C and P=0.09-0.21 GPa for the augite, and T=867-1,039 °C and P=0.40-0.60 GPa for the pigeonite. These results suggest a relatively rapid magma ascent for the tholeiitic products as well as an evolution mostly through fractional crystallization. The LILE elements enrichment, the negative trend in the FeOt, TiO2 and CaO versus SiO2 content, together with some disequilibrium textures, are also evidence of crustal contamination and magma recharge. Thus it is proposed that the Combia Volcanic Province started as a simple magmatic system, where the tholeiitic products were generated by a relatively rapid magma ascent. Then, a more complex magmatic system linked to long-term magma stagnation, allowed melt evolution to form calc-alkaline magmas as previously defined.pp.181-20