La Capa de conglomerado-brecha de la Llosa del Cavall (Solsona, Lleida): características sedimentarias

Marc Divins; Ferran Colombo

doi:10.55407/geogaceta102468

Authors

Marc Divins Departament de Dinàmica de la Terra i de l’Oceà. Facultat de Ciències de la Terra. Universitat de Barcelona
Ferran Colombo Departament de Dinàmica de la Terra i de l’Oceà. Facultat de Ciències de la Terra. Universitat de Barcelona

DOI:

https://doi.org/10.55407/geogaceta102468

Keywords:

key bed, alluvial, event, Ebro Basin, lateral facies change

Abstract

The Llosa del Cavall bed is a conglomerate-breccia layer of great lateral continuity that presents two groups of lithofacies. The first group consists of units with massive, graded bedding facies, with a fabric that can be clast or matrix-supported. The matrix is essentially made up of carbonates with a high percentage of fine-grained particles (silt-clay size). It also contains soft-sediment deformation structures (water-escape and loading), plant remains, armoured mud balls, outsized boulder clasts and various erosive structures due to currents. The second group includes a wide range of tractive facies, evidenced by features such as planar or low angle lamination/stratification, graded bedding, cross-bedding, mud balls and intraformational clasts. The first group of lithofacies was generated by high-density flows that were mainly unconfined. The second group of lithofacies corresponds to high to low-density flows with or without confinement that tend to be diluted. Lateral and vertical lithofacies changes resulted from gradual flow transformations such as changes from high-density gravity flows to low-density currents.

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