Caracterización geoquímica de las areniscas del Cretácico inferior de la cuenca del Maestrazgo, Cadena Ibérica Oriental: Nueva aportación al estudio de la procedencia

Abstract

A geochemical characterization (major, trace and rare earth element abundances) of the Lower Cretaceous sandstones of the Maestrat Basin has been carried out, in order to discriminate samples from different formations and assess their provenance and weathering conditions. All the studied sandstones are arkoses and subarkoses characterized by a multi-elemental diagram showing enrichment in Rb, U, La, Nd, Zr and Y, and depletion in Ba, Nb, Sr, P and Ti, which is typical of calc-alkaline igneous rocks. This pattern suggests an input from igneous rocks directly from the source area or by recycling. The low chemical index alteration values do not reflect intense weathering conditions in the source region. Sandstones from the studied formations were discriminated using a Rb versus Y+Nb plot. This plot shows a progressive Rb enrichment and Y+Nb depletion toward the uppermost sandstones (Camarillas Tm). Rb versus K20 indicates a good positive correlation, which is consistent with the observed Kfeldspar abundance increase towards the Camarillas sandstones. The higher SREE and Y+Nb ratios in Mora Em. sandstones suggest a slight difference in provenance, which can be explained by the contribution of Paleozoic shales and metasediments.