Oligo-miocene unconformities in north otago and the tasman sea

Abstract

The stratigraphie ranges of key planktonie foraminifera, in Oligo-Miocene sections at Kokoamu Cliff and Earthquakes in North Otago and in the Deep Sea Drilling Project Site 593 in the Tasman Sea, have been correlated with a recently published time-scale. There appear to be two unconformities at Kokoamu Cliff, with durations of c. 2 Ma and c. 5 Ma; two at Earthquakes, with c. 2 Ma and c. 6.4 Ma intervals; and at the DSDP Site 593 a possible unconformity with a duration of c. 7 Ma. An alternative postulate, that there are no time-signifieant unconformities in the North Otago sections, is also considered, and the problem of the Dontroonian Stage discussed. © 1987 Journal of the Royal Society of New Zealand.