Abstract

Three depositional sequences in the sense of Vail (1987) are defined in the Middle and Upper Eocene deposits of the NE Ebro Basin. These sequences are correlated along the SE border of the basin in the area of deposition of the deltaic complexes of St. Llorenc del Munt, Gallifa and St. Feliu de Codines. The sedimentation took place during a period of block-differentiation of the basin margin, which induced thickness variations in the depositional areas. Although the tectonic-sedimentation evolution model that we propose shows the control of the paleogeography by tectonics, the sequence stratigraphy of the alluvial and deltaic complexes is influenced by the relative sea-level changes.

Introduction

The area studied is located on the SE side of the Catalan Central Depression (NE Ebro basin), close to the Catalan Coastal Ranges (Fig. 1). During Paleogene times, the NE margin of the Ebro Basin was rilled with predominantly clastic terrigenous deposits which formed several deltaic complexes. The purpose of this chapter is to analyse and compare the sequence stratigraphy and the facies distribution patterns of the Eocene St. Llorenc del Munt and St. Feliu de Codines–Gallifa deltaic complexes, and find the relationships between tectonics and sedimentation for this side of the NE Ebro basin margin.

The strike–slip tectonics of the NE margin of the Ebro basin was contemporaneous with the sedimentation of the Paleogene deposits. Thus, the facies distribution of these materials near the basin margin is strongly controlled by the evolution of thrusting and fault development (Anadón et al., 1985).