Late and postmagmatic alterations in the tin-bearing batholith of Ricobayo (Iberian Massif, NW Spain)

The deuteric alteration processes undergone by the granites of the Ricobayo Batholith were: microclinization, chloritization, albitization, muscovitization, tourmalinization and garnetization. These processes must be interpreted in a dynamic context so that the different reactions that take place are the consequence of a successive interaction between rock and fluids. The physicochemical conditions deduced from these fluids are: temperature lower than 600 OC, pressure between 1.5 and 1 Kb, fugacity of oxygen between 10-25 and 10-35 bars, fugacity of sulphur lower than 10-l5 bars, the composition was kept stable and their log (a(K+)/a(Ht)) and log (a(Na+)/a(H+)) varied between 3.8 and 3.2 and between 3.5 and 4.6, respectively, and the pH of the fluids was higher than 5 during the microclinization, muscovitization and tourmalinization, and lower during chloritization and albitization. The deposition of cassiterite occurs with pH episodes that exceed 5.

Estado de los diarios digitales en República Dominicana : enero-julio, 2014

La presente investigación analiza la situación de los medios digitales en la República Dominicana, con el objetivo de realizar una serie de recomendaciones para la mejora de estos medios online emergentes. Se persigue cambiar la percepción que los medios digitales tienen que estar escudados en grandes cabeceras, estos pueden ser autónomos y completamente digitales sin la necesidad de una versión impresa del mismo. También hay que considerar que el Ciberperiodista debe contar con ciertas destrezas y habilidades para la administración de estos diarios digitales.