Abstract

The general definition and recognition criteria of ‘tectosedimentary units’ (TSUs) are described and discussed. The nonmarine sediments of the Iberian margin of the Ebro basin are divided into tecto-sedimentary units. Eight of these units (labelled T1 to T8) are described from the area; their ages range from Thanetian (Late Paleocene) to Turolian (Late Miocene).

Introduction

The Tertiary sediments of the Iberian margin of the Ebro basin were deposited in alluvial and lacustrine systems and mostly derived from this same margin. In these continental sediments detrital-clastic and evaporitic facies dominate, so there is a scarcity of fossiliferous beds, and chronostratigraphic and correlation studies using fossils are very difficult.

In contrast to the classical methods of stratigraphy, present methods of basin analysis are often concerned with the division of the basin-fill into ‘genetic units’. These units are defined by objective criteria that result from events that are thought to have affected the whole basin (Vera, 1989). We have followed this approach in our study of the southern margin of the Ebro basin using the ‘tectosedimentary analysis’ of Garrido-Megias (1973, 1982). This method is based on analysis of sequence evolution and the large-scale geometry of sedimentary bodies and results in the division of the basinfill into tectosedimentary units (TSUs).