Latest Cretaceous/earliest Tertiary transition on Seymour Island, Antarctica

Seymour Island, Antarctica (64°17'S), offers the first opportunity to examine the crisis at the end of the Cretaceous from the high southern latitudes. The K/T boundary sequence on Seymour Island consists of a nearly continuous sequence of siliciclastic sediments deposited in a mid-shelf environment. The faunal changes across the boundary occur through a 30-m interval with no single extinction horizon, in contrast to other well-studied K/T boundary sections. The “expanded” nature of the Seymour Island section makes placement of the K/T boundary difficult because boundary indicators such as planktic foraminifera, ammonites, and dinocysts disappear at different levels within the section.