Javier Carrillo-Rosúa

Textural and chemical features of sphalerite from the Palai-Islica deposit (SE Spain): implications for ore genesis and color

Este articulo ha sido publicado en la revista Neues Jahrbuch fur Mineralogie – Abhandlungen, correspondiendo la presente version a un preprint

SIGNIFICANCE OF PHYLLOSILICATE MINERALOGY AND MINERAL CHEMISTRY IN AN EPITHERMAL ENVIRONMENT. INSIGHTS FROM THE PALAI-ISLICA Au-Cu DEPOSIT (ALMERÍA, SE SPAIN)

Phyllosilicate mineralogy is key to understanding hydrothermal processes within accepted epithermal deposit models but little information has been published about the mineral chemistry of epithermal deposits. X-ray diffraction, optical and electronic microscopy (scanning and transmitted), electron microprobe, and Fourier transform infrared spectroscopy were used in this work to study phyllosilicates in the Palai-Islica Au-Cu epithermal, volcanic-hosted deposit, in order to link phyllosilicate mineralogy and mineral chemistry to ore genesis. Different phyllosilicate assemblages are characteristic of two types of mineralization, and related hydrothermal alteration. Chlorite and mica appear in polymetallic quartz veins with sulfides, and in the related chloritic and sericitic hydrothermal alteration. These minerals have notable textural and chemical differences (i.e. Fe/(Fe+Mg), Si and Al in chlorite and illitic and phengitic components in mica) amongst veins and altered rocks, revealing different genetic conditions. These chemical features also distinguish propylitic and regional, non ore-related, low-temperature alteration. Hot hydrothermal fluids of near-neutral pH are responsible for vein mineralization and alteration. Illite, interstratified illite-smectite, kaolinite, and pyrophyllite are characteristic, with a distribution pattern by zones, of the intermediate argillic and advanced argillic alteration around areas of silicification. In the latter, native gold appears associated with interstratified illite-smectite, suggesting a relatively low-temperature formation. Hot, low-pH fluids are responsible for this mineralization and alteration assemblage. The present study contributes to epithermal models showing the co-existence of two different alteration styles in the same hydrothermal system.

VALIDACIÓN DE UN REGISTRO DE OBSERVACIÓN, PARA ANALIZAR INTERACCIONES DE ÉXITO, EN UN GRUPO INTERACTIVO EN COMUNIDADES DE APRENDIZAJE

espanolEl presente trabajo consiste en una validacion de un registro de observacion, para grupos interactivos en Comunidades de Aprendizaje. Pretende analizar en que medida las interacciones, que se producen en los grupos interactivos, son de exito. Comunidades de Aprendizaje es un proyecto que resalta la importancia de dos factores: la interaccion y la participacion de la comunidad escolar. En cuanto a los grupos interactivos, se trata de agrupaciones heterogeneas del alumnado, en pequenos grupos, que trabajan en una misma actividad, dinamizados por un voluntario. La validacion consta de dos partes: en la primera, se realizo una revision de la literatura cientifica y, en la segunda, se llevo a cabo el metodo de panel de expertos, contando con una muestra de 16 expertas y expertos, pertenecientes al Plan de Voluntariado de Comunidad de Aprendizaje dela Universidadde Granada. La metodologia usada se basa en un diseno transversal. Los resultados mostraron el instrumento como valido; para ello, los datos se analizaron mediante el calculo del coeficiente de correlacion intraclase y un analisis de varianza de facetas obteniendo una elevada significacion. Por ultimo, se relacionan los items con diferentes aportaciones de autores y, ademas, se elaboran recomendaciones para la teoria y la practica profesional, asi como sugerencias para futuras investigaciones. EnglishThis paper consists in a validation of an observation record, for interactive groups in Learning Communities. The aim of the observation record is to analyze, up to what extent, the interactions that occur in the interactive groups are successful. Learning Communities is a project, which includes: interactions and participation of the school community. This project is made up of several interventions, one is Interactive groups are heterogeneous groups of students, working on the same activity and coordinated by a volunteer. The validation include: a review of the literature and an expert panel implementation, with the participation of 16 experts, they were participating in the Plan Learning Community Volunteer at theUniversityofGranada. The methodology is based on a transversal designed. The results showed the instrument as valid. The data were analyzed by calculating the intraclass correlation coefficient and analysis of variance, obtaining high significance. Finally, the items of an observation record and other research were connected to demonstrate consistency. In addition, there are a series of advices for using the observation record in practice, as well as suggestion for line of research in the future.