A global taxonomic and biometric study of the radiolarian genus Pterocanium defines 5 major lineages over the last 6 million years: Pterocanium charybdeum, P. praetextum, P. korotnevi, P. prismatium, and P. audax. P. charybdeum is divided into 4 subspecies:

Magnetic polarity stratigraphies from ODP Leg 177 ‘high resolution’ sites indicate Brunhes sedimentation rates in the 12–25 cm/kyr range, with a trend of decreasing sedimentation rates with increasing age. Magnetite is the principal remanence-carrying

Micropaleontological studies have been carried out on seven cores of middle Pliocene to early Pleistocene age (lower to upper Matuyama; t = 0.7 to 2.43 m.y. BP) from northern Antarctic and Subantarctic waters south of Australia and New Zealand. All of