Evidence for an open seaway between northern and southern proto-Atlantic in Albian times

Abstract

SINCE Wegener1 presented his hypothesis on the origin of continents and oceans much effort has been centred on the dating of the first opening of a southern proto-Atlantic and on that of a first connection between the southern and northern Atlantic. Based on data from seafloor spreading, palaeomagnetism and the stratigraphy of the coastal basins flanking the Atlantic it was suggested that the opening of the southern Atlantic began in the Early Cretaceous2–3. According to the pattern of faunal distribution an open seaway with a free interchange of faunas should not have been established until the Lower Turonian4–5 though some authors6–7 argue for an earlier opening in Albian times. We report here that new ammonite faunas from south-east Nigeria reveal a marine connection in Late Albian times.