Appendix: Oligocene unconformities in the South Island

Abstract

Oligocene unconformities are widespread throughout New Zealand (Carter and Landis, 1972) and the southwest Pacific (Kennett et al., 1974). The expression of these unconformities is often subtle, so that some investigators have failed to record their presence in carefully examined sections (e.g. Eade and Kennett, 1962). Ward and Lewis (1975) and Nathan (1978a) have even included sediments from above and below such unconformities in single formations, on the grounds of superficial lithological similarity. It is our experience that these unconformities are regionally significant, and that one or more Oligocene unconformity is present in all DSDP sites drilled in the New Zealand region (Kennett et al., 1974), and in all known onland shallow marine sections (Carter and Landis, 1972; see also summary columns in Findlay, 1980), being unreported only in areas of Oligocene flysch sedimentation as in the Waiau and Murchison basins.