Diagenetic albitization in the Tera Group, Cameros Basin (NE Spain) recorded by trace elements and spectral cathodoluminescence

This paper deals with the diagenetic albitization of both plagioclases and K-feldspars in the Tithonian fluvial sandstones of a rift basin (Cameros Basin). The sandstones in the lower part of the rift record have not suffered this albitization process. A clear relationship is observed between sodium contents, as the main element of some feldspars and their cathodoluminescence (CL) color (the higher the sodium content, the lower is their CL intensity). In conclusion, albitization processes are detectable by decreased CL intensities and changes in the CL spectra. In addition, very different trace element compositions are obtained by laser ablation when comparing trace elements of non-albitized feldspars in sandstones of the lower part of the rift record with those of albitized feldspars in sandstones of the infill top. Non-albitized K-feldspars show Rb, Sr, Ba and Pb contents of up to 1000ppm. In contrast, very flat profiles of trace element contents (