Mesozoic stratigraphy of the Goban Spur, offshore south-west Ireland

Abstract

A Mesozoic stratigraphic framework for the Goban Spur, offshore Ireland is proposed based on results of the 62/7-1 well. This study integrates the well, Deep Sea Drilling Project data and 3000 km of seismic profiles into a stratigraphic analysis showing vertical and lateral associations of facies in the Mesozoic evolution of the basin. Basin development is believed to have been initiated during the Triassic. The discussed geological section is restricted to the Sinemurian to Maastrichtian interval. Two major hiatuses are recognized with the Late Jurassic and the Turonian absent. They reflect the ‘Middle Cimmerian’ predominantly tectonic event and a mid-Cretaceous predominantly eustatic event, respectively. Significant Middle Jurassic volcanic activity is associated with the Middle Cimmerian tectonism. The breakup unconformity is present between Late Barremian or Early Aptian and Early Albian deposits. Detailed biostratigraphic analyses and palaeoenvironmental interpretations indicate close affinities with adjacent offshore southern Ireland, southern England and eastern offshore Canada. Implications for hydrocarbon exploration are discussed with particular emphasis on the potential source and reservoir characteristics.