Integrated stratigraphy of the Waitakian-Otaian Stage boundary stratotype

The base of the type section of the Otaian Stage at Bluecliffs, South Canterbury, is recognised as the stratotype for the boundary between the Waitakian and Otaian Stages. Principal problems with the boundary are the restriction of existing bioevent proxies to shelf and upper slope environments and its uncertain age. These topics are addressed by a multidisciplinary study of a 125 m section about the boundary, which examines its lithostratigraphy, depositional setting, biostratigraphy, correlation, and geochronology. The Waitakian-Otaian boundary is dated at 21.7 Ma by strontium isotopes. Stable primary remanence could not be determined in a pilot paleomagnetic study of Bluecliffs specimens. However, specimens trended towards reversed polarity, and remagnetisation great circle analysis will allow directions to be calculated in future collections. (author). 91 refs., 4 tabs., 15 figs