Origin and nature of the aluminium phosphate-sulfate minerals (APS) associated with uranium mineralization in triassic red-beds (Iberian Range, Spain)
This study focuses on the mineralogical and chemical study of an Aluminium–phosphate–sulphate (APS) mineralization that occurs in a clastic sequence from the Triassic (Buntsandstein) of the Iberian Range. The deposit is constituted by sandstones, mudstones, and conglomerates with arenaceous matrix,...
| Autores: | , , |
|---|---|
| Tipo de recurso: | artículo |
| Fecha de publicación: | 2013 |
| País: | España |
| Institución: | Universidad Complutense de Madrid (UCM) |
| Repositorio: | Docta Complutense |
| Idioma: | inglés |
| OAI Identifier: | oai:docta.ucm.es:20.500.14352/34670 |
| Acceso en línea: | https://hdl.handle.net/20.500.14352/34670 |
| Access Level: | acceso abierto |
| Palabra clave: | 549 553.4(460) (460)553.4 551.761(234.1) (234.1)551.761 APS minerals U-bearing sandstones Diagenesis Triassic Buntsandstein Iberian Range Spain minerals APS minerals areniscas uraníferas Diagénesis Triasico Buntsandstein Cadena Ibérica España Mineralogía (Geología) 2506.11 Mineralogía |
| Sumario: | This study focuses on the mineralogical and chemical study of an Aluminium–phosphate–sulphate (APS) mineralization that occurs in a clastic sequence from the Triassic (Buntsandstein) of the Iberian Range. The deposit is constituted by sandstones, mudstones, and conglomerates with arenaceous matrix, which were deposited in fluvial to shallow-marine environments. In addition to APS minerals, the following diagenetic minerals are present in the clastic sequence: quartz, K-feldspar, kaolinite group minerals, illite, Fe-oxides-hidroxides, carbonate-sulphate cement-replacements and secondary uraniferous minerals. APS minerals were identified and characterized by optical microscopy, X-ray diffraction, scanning electron microscopy, and electron microprobe. Microcrystalline APS crystals occur replacing uraniferous minerals, associated with kaolinite, mica and filling pores, in distal fluvial-to-tidal arkoses-subarkoses. Given their Ca, Sr, and Ba contents, the APS minerals can be defined as a solid solution of crandallite-goyacite-gorceixite (0.53 Ca, 0.46 Sr and 0.01 Ba). The chemical composition, low LREE concentration and Sr > S suggest that the APS mineral were originated during the supergene alteration of the Buntsandstein sandstones due to the presence of the mineralizing fluids which causes the development of Ubearing sandstones in a distal alteration area precipitating from partially dissolved and altered detrital minerals. Besides, the occurrence of dickite associated with APS minerals indicates they were precipitated at diagenetic temperatures (higher than 80ºC), related to the uplifting occurred during the late Cretaceous post-rift thermal stage. |
|---|