High latitude, late Campanian (Cretaceous) Radiolaria from offshore south-eastern Tasmania

Abstract

A well-preserved, low diversity (ten species), high latitude (palaeolatitude 70°S) radiolarian fauna is recorded from shallow-water late Campanian (Late Cretaceious) sediments recovered in cores taken from the continental slope of southeastern Tasmania. These are the first Radiolaria described from Cretaceous rocks of southeastern Australia. Most forms are previously described species but a new species of Petasiforma is described. Age control is provided by dinoflagellates but the radiolarian fauna is similar to late Campanian-Maastrichtian faunas described from Campbell Plateau. A late Campanian age can also be determined from the Radiolaria, which are correlated with the Patulibracchium dickinsoni Zone. The site has subsided some 3200 m since deposition, at an average rate of about 40–45 m/Ma, consistent with other indicators in the region. Radiolaria are similar to other coeval plankton in exhibiting high latitude characteristics.

Keywords:

• Cretaceous
• Campanian
• Radiolaria
• Tasman Sea
• Tasmania