The Dunedin volcanic group is a recent reclassification due to common magma melt ancestry of the Dunedin Volcano, with the overlapping alkali basaltic monogenetic volcanic field which was known in earlier literature as the Waiareka-Deborah volcanic group or Waiareka volcanic field. Importantly excluded from the group are a group of volcanics of different composition (sub-alkaline basalt to basaltic andesite) and older age (36.4 to 27.6 million years ago) near Oamaru now termed the Waiareka-Deborah volcanic field. Confusingly the older Waiareka-Deborah volcanic field overlaps the Dunedin volcanic group geographically and high quality composition studies still need to be done to properly classify many volcanics near Oamaru. The Dunedin volcanic group covers over of Otago in the South Island of New Zealand. Geography The most significant volcanic features are those that define the city and harbour of Dunedin but the multiple monogenetic basalt volcanoes alter the mainly sedimentary Otago landscape. In the case of Foulden Maar one eruptive centre provides a unique means to access the fossil record of New Zealand as of 23 million years ago when it was sub tropical forest. The most northern eruptive centre is at Arnmore near Ngapara and the group extends south to near Kaitangata away. While the most easternmost on-land occurrence is at Lookout Bluff in north Otago there is evidence of offshore underwater centres from seismic data. Haughton Hill in the Maniototo is the most northwestern eruptive centre. Geology There are over 150 flows or eruptive centres known and these are mainly small volume alkaline basanites. The Dunedin volcanic group still has evidence of a magma melt hot spot centred near Portobello on the Otago Peninsula that has presumably been accumulating in the last 10 million years since active volcanism ceased, as backed up by surface helium measurements. In this region of Otago there is a Jurassic through to Cretaceous metamorphosed belt known as the Otago Schist that formed as part of the Zealandia continent In the north of the Oligocene through to Miocene aged volcanic group the basement rocks are pumpellyite to actinolite greyschist, then lower greenshist before the upper greenschist belt from Wanaka doen to Dunedin. The southern volcanics again erupted through upper greenschist and pumpellyite to actinolite greyschist. The Otago Schist is overlain by a sedimentary sequence deposited from Late Cretaceous to Miocene time. The peak of marine transgression is marked by an Oligocene carbonate platform that represents near-total continent submergence