Late Cretaceous and Paleocene terrestrial climates of New Zealand: leaf fossil evidence from South Island assemblages

Univariate and multivariate leaf morphology-based analysis of leaf fossil assemblages from localities in the South Island of New Zealand provide quantitative paleoclimate estimates for the terrestrial Late Cretaceous and Paleocene. Favourable growing conditions with a cool to mild temperate climate are inferred for the youngest pollen zone in the Late Cretaceous (PM2) with moderately high precipitation and high dicotyledonous angiosperm diversity. Mean annual temperature estimates of c. 12-16 and c. 7-11degreesC were produced from northwest Nelson and North Otago PM2 Zone assemblages, respectively. These different temperature estimates most likely reflect differences in age, although geographic differences may also be a factor. Consistent data from three Paleocene assemblages suggest cool-temperate conditions. Mean annual temperature estimates of c. 6-12degreesC were produced from these Paleocene assemblages. They also had lower dicotyledonous leaf diversity than the Late Cretaceous assemblages, no more than 30 different angiosperm leaf forms.