Mineralogy, chemistry and palaeoenvironmental significance of an Early Tertiary Terra Rossa from Northern Ireland: A preliminary review

Early Tertiary basalts of the Antrim Plateau have preserved palaeosols developed on late Cretaceous limestone. These palaeosols include dark red clays and clays with flints that are rich in silica and contain a complex clay mineral assemblage of 2:1 lattice clays, kaolinite and sepiolite. They occur in infilled solution hollows and joints, can be associated with a rudimentary tower karst and are similar in appearance and composition to present-day Mediterranean terra rossa soils. Elsewhere, grey flint-rich clay-sized material dominated by silica and kaolinite developed on an undulating landscape, sometimes now capped by a lignite horizon. Deposits and the palaeolandscape suggest a humid tropical to sub-tropical environment contrary to previous published inferences of arid conditions, but corresponding to humid tropical conditions proposed for the formation of overlying inter-basaltic soils.