Aplicación del método K-Ar a la datación de fenómenos de metamorfismo de muy bajo grado en sistemas máficos. Cordillera de los Andes, Chile Central

Fichero original en: http://www.ehu.eus/sem/macla_pdf/macla6/Macla6_323.pdfEn el presente trabajo se presenta la aplicación del método K-Ar aplicado a celadonitas y otros filosilicatos ricos en K desarrollados en rocas volcánicas y volcanoclásticas de la Cordillera de la Costa y de los Andes de Chile central. El significado de la edad obtenida por estos métodos permitirá ayudar a comprender la historia evolutiva de estos sectores del orógeno andino.Universidad de Granada. Departamento de Mineralogía y PetrologíaEstre trabajo se ha realizado con fondos procedentes del proyecto BTE-2003-06265 (MEC/FEDER), del proyecto Fondecyt (Chile 1031000, Fundación Andes (C-13680/3) y el proyecto REIN 02/2003 del Departamento de Investigación de la Universidad de Chile y del Grupo de Investigación RNM131 de la Junta de Andalucía. J. Carrillo agradece al MEC su beca postdoctoral

Spatial and temporal assessment of fragmentation and connectivity analysis for ecotourism activities in a RAMSAR site: Bañados de Isoso (Santa Cruz, Bolivia)

Protecting biodiversity in RAMSAR sites through conservation activities, like ecotourism, can be very useful to maintain ecological function. There are very few studies in Bolivia that incorporate landscape ecology as a strategic vision for ecotourism in general, and even less that focus on wetlands systems. The aim of this research was to assess the degree of fragmentation and structural connectivity in the landscape in order to understand the anthropogenic processes that have influenced Bañados de Isoso (Santa Cruz, Bolivia) in the last 30 years. To achieve this we used land use change coverage for the Bolivian lowlands (1976-2005) and we quantified changes in vegetation patterns and connectivity through moving windows and spatial sampling based on the scale of a typical ecotourism circuit. The most significant changes occurred after the 1990s with more than 40% natural habitat loss in the northwest and 10-20% in the south. Mean patch areas decreased by more than 75% and patch density increased over 20 times during the same period, indicating a high degree of fragmentation. Connectivity decreased by 5% between 1976 and 2005. Our results show the value of using landscape metrics to assess the impact of human activities within RAMSAR sites and how these activities can be used to encourage strategies, such as ecotourism, to promote landscape conservation

K–Ar and ⁴⁰Ar/³⁹Ar geochronology of supergene processes in the Atacama Desert, Northern Chile: tectonic and climatic relations

<p>New K–Ar and ⁴⁰Ar/³⁹Ar data obtained for 29 samples of supergene alunite-, jarosite- and hollandite-group minerals from the Central Depression of Northern Chile document almost continuous supergene oxidation from 33 to 9 Ma. The downward migration of supergene oxidation zones is used to calculate maximum denudation rates of 16–35 m Ma⁻¹. These calculated rates are sensitive to pre-existing topography and show that the present relief observed in the Central Depression represents a modified Miocene landscape. The results presented here are in good agreement with previously published geochronological data for the Atacama Desert. The combination of all published data, including the results presented here, defines a continuous skewed distribution, with a maximum between 21 and 14 Ma. The relative paucity of ages greater than 30 Ma reflects the removal of supergene profiles by erosion during and immediately after the Incaic compressive deformation. From 29 to 9 Ma, supergene oxidation profiles were generated under semi-arid conditions throughout the Atacama region. Ages between 9 and 5 Ma on the northern and southern margins of the desert mark the end of supergene oxidation processes, consistent with a Pliocene onset of present-day hyperaridity. </p

Variation in the Composition of the Essential Oil of Senecio Filaginoides Dc

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Cuaderno de Trabajo Social N° 11

127 p.Esta publicación contiene los siguientes artículos: DESGASTE POR EMPATÍA: Cómo ser un profesional del trabajo social y no desfallecer en el intento ; TRABAJO SOCIAL Y ENVEJECIMIENTO EN CHILE: Una revisión a los lineamientos, metodologías y políticas públicas ; LA VULNERACIÓN DE DERECHOS EN LA POBLACIÓN USUARIA COMO MANIFESTACIÓN DE VIOLENCIA SIMBÓLICA EN SALUD. Informe de sistematización ; EL DESAFÍO DE LA INTERVENCIÓN PÚBLICA EN LOS HOGARES CON DEPENDIENTES Y SU RED APOYO: Hitos en la implementación del programa red local de apoyos y cuidados en la comuna de Rancagua ; CONFLICTOS SOCIOAMBIENTALES EN COMUNIDAD QUECHUA CEBOLLAR ASCOTAN, DE LA REGIÓN DE ANTOFAGASTA ; INNOVACIONES CONCEPTUALES PARA EL TRABAJO SOCIAL INTERCULTURAL. Experiencia del programa pueblos originarios en Recoleta