Chapter 17 - Salt and Strike-Slip Tectonics as Main Drivers in the Structural Evolution of the Basque-Cantabrian Basin, Spain

Abstract

An overview of the structural evolution of the Basque-Cantabrian Basin (BCB) based on surface geological data, exploration wells and 2D seismic is summarized in four geological N-S cross sections. Most of the folds and thrusts of the BCB are reflected in these cross sections, including some notable structures of the basin, which were originated due to Late Jurassic-Early Cretaceous salt tectonics. The main salt-related structures and their influence in the Late Jurassic-Early Cretaceous sedimentation in the basin are highlighted. The structure of the eastern and western zones of the basin evolved differentially as a result of contrasting initial rift geometries. The difficulty of any structural reconstruction of the BCB using a uniform orientation of the main shortening direction uniquely is discussed. The Tertiary compression has produced an important shortening in both the Mesozoic cover and the basement, where a strike-slip (transpressive) tectonic model is proposed to accommodate the deformation of the sedimentary cover. Salt tectonics is also demonstrated to have played an important role in some of the petroleum system processes in the BCB, controlling the hydrocarbon trap generation, as well as the geochemical evolution and maturation of the source rocks.