Gas discharges for continental Spain: geochemical and isotopic features

In this work the results of a geochemical and isotopic survey of 37 gas discharges was carried out in continental Spain are presented and discussed. On the basis of the gas chemical composition, four different areas can be distinguished, as follows: 1) Selva-Emborda (SE) region; 2) Guadalentin Valley (GV); 3) Campo de Calatrava (CC) and 3) the inner part of Spain (IS). The SE, GV and CC areas are characterized by CO2-rich gases, while IS has N2 as main gas compound. The CO2-rich gases can be distinguished at their turn on the basis on the helium and carbon isotopic composition. The SE and CC areas have a strong mantle signature (up to 3 Ra). Nevertheless, the carbon isotopic composition of CC is within the mantle range and that of SE is slightly more negative (down to -8‰ PDB). The GV gases have a lower mantle signature (61 Ra) with respect to SE and CC and more negative carbon isotopes (6-10‰ PDB). It is worth to mention that the SE, GV and CC areas are related to the youngest volcanic activity in continental Spain, for example the Garrotxa Volcanic Field in Catalonia records the latest event dated at 10,000 years, and the isotopic features, particularly those of helium, are suggesting the presence of magmatic bodies still cooling at depth. The N2-rich gases, i.e. those from the IS area, has an atmospheric origin, as highlighted by the N2/Ar ratio that ranges between those of air and ASW (Air Saturated Water). The isotopic composition of carbon is distinctly negative (down to -21‰ PDB) and that of helium is typically crustal (0.02-0.08 Ra), confirming that these gas discharges are related to a relatively shallow source.

Paul Frankl, Rudol Wittkower, Colin Rowe. Tres enfoques histórico-formales para el estudio de la arquitectura

Los estudios de la arquitectura vinculados al enfoque formalista tienen tres libros entre sus referencias principales: Principios fundamentales de la Historia de la Arquitectura. El desarrollo de la arquitectura europea, 1420-1900, de Paul Frankl; Los fundamentos de la arquitectura en la edad del humanismo, de Rudolf Wittkower; y Manierismo y arquitectura moderna y otros ensayos, de Colin Rowe. Estas obras responden a planteamientos muy distintos, pero tienen en común el papel relevante que el método formal juega en ellas. La actividad intelectual de estos estudiosos ha de relacionarse con la de otros autores anteriores o coetáneos. En el caso de Frankl sus vinculaciones principales son con Wölffl in y Schmarsow, entre otros. El libro de Wittkower es deudor de los enfoques de Goldschmidt y de Panofsky y se distancia de los planteamientos de Scott y del propio Wölffl in. Colin Rowe se apoya en los escritos de Wittkower y reconoce la utilidad del método de Wölffl in, aunque señala sus limitaciones. Como se ve, la figura de Wölfflin está presente desde el principio hasta el final de esta historia.