Composición y procedencia de los sedimentos detríticos del Cretácico Inferior de las subcuencas occidentales de la cuenca del Maestrazgo.

Abstract

A thick succession of Lower Cretaceous, predominantly continental clastic sediments ("Weald" facies) crop out in the westernmost sub-basins of the Maestrazgo Basin (eastern Iberian Range, Spain). 62 sandstone samples from the Mora, Castellar, and Camarillas Fms. have been thin sectioned and studied using transmitted-light and scanining electron microscopy, and 4 1 samples were point counted (300-400 points per thin section). The sandstones of the Mora and Castellar Fms. are similar, having mean compositions of QH,FHRh and Q86F10R4, respectively. They are relatively rich in plagioclase and metamorphic rock fragments, lacking K-feldspar. The sandstones of the Camarillas Fm. have mean compositions of Q7gFuR8 (Pehagolosa subbasin) and Q75F,,R, (Calve andAliaga subbasins). They are relatively rich in K-feldspar and, locally, in plutonic rock fragments. In all the studied sandstones, the diagenesis has changed significantly the depositional abundances in feldspar, which is partly dissolved or replaced by kaolin and calcite. The sandstones of the Mora and Castellar Fms. derive in part from low- and medium-grade metamorphic terrains. In contrast, the sandstones of the Camarillas Fm. derive in part from crystalline terrains that were located to the W or NW.