An early Holocene occurrence of the mangroveAvicennia marinain Poverty Bay, North Island, New Zealand: Its climatic and geological implications

Abstract

Pollen evidence indicates that the mangrove Avicennia marina var. resinifera (Forst. f.) Bakh. (Avicenniaceae) once occurred in Poverty Bay, and its presence is used as evidence for warm climate following the last glaciation. Radiocarbon dates indicate a maximum time of 9840 ± 190 years B. P. (NZ 6309B) * New Zealand Radiocarbon Dating Laboratory sample number with age based on the new half life uncorrected for secular effects, as are all other radiocarbon ages in the text of this paper. See Table 1. View all notes for this warm climate event, coinciding with the Holocene climatic optimum. The mangrove is currently found c. 1° further north in the Bay of Plenty. The climatic implications of the pollen data when considered with macrofaunal determinations, sediment lithologies, depositional environments, and radiocarbon dates show that the early postglacial in Poverty Bay was a time of complex depositional and erosional conditions associated with the postglacial rise in sealevel, local tectonic activity, and the concomitant change in coastal geomorphology. A full description of the pollen of extant Avicennia marina var. resinifera is presented.