Upper-Pleistocene terrace deposits in Mediterranean climate: geomorphological and source-rock control on mineral and geochemical signatures (Betic Cordillera, SE Spain)

Mineral and chemical composition of alluvial Upper-Pleistocene deposits from the Alto Guadalquivir Basin (SE Spain) were studied as a tool to identify sedimentary and geomorphological processes controlling its formation. Sediments located upstream, in the north-eastern sector of the basin, are rich in dolomite, illite, MgO and KB2BO. Downstream, sediments at the sequence base are enriched in calcite, smectite and CaO, whereas the upper sediments have similar features to those from upstream. Elevated rare-earth elements (REE) values can be related to low carbonate content in the sediments and the increase of silicate material produced and concentrated during soil formation processes in the neighbouring source areas. Two mineralogical and geochemical signatures related to different sediment source areas were identified. Basal levels were deposited during a predominantly erosive initial stage, and are mainly composed of calcite and smectite materials enriched in REE coming from Neogene marls and limestones. Then the deposition of the upper levels of the alluvial sequences, made of dolomite and illitic materials depleted in REE coming from the surrounding Sierra de Cazorla area took place during a less erosive later stage of the fluvial system. Such modification was responsible of the change in the mineralogical and geochemical composition of the alluvial sediments.

De la metafísica a la anarquía. El pensamiento político de Reiner Schürmann

El artículo pretende abordar el modo en el que la obra de Reiner Schürmann, a través de un original interpretación del pensamiento de Martin Heidegger, consigue desarrollar un tipo de filosofía política anárquica. Se intentará analizar, en la dispersa obra del filósofo holandés, la idea de anarquía como condición existencial, prestando especial atención al nexo entre el concepto de muerte de la metafísica y la posibilidad de una praxis política anárquica. El artículo se compone de tres partes: en la primera se examinará la noción de Ser y de “a priori práctico” en el trabajo de Schürmann. En la segunda se verá la diferencia entre el nihilismo del autor y el de Vattimo, y en la tercera, se profundizará en las consecuencias más propiamente políticas del pensamiento de Schürmann.