A book spanning the 2.6 million year geological history of Mount Pirongia – the first such comprehensive publication of its kind in New Zealand – was launched at the Pirongia Heritage Centre on November 18 by its author, Dr Oliver McLeod of the Earth Sciences Department at the University of Waikato.
The book, entitled ‘Geology of the Pirongia Volcano, Waikato: 1:30,000 Geological Map’, is published by the Geoscience Society of New Zealand and represents the final requirement of Oliver’s PhD on ‘The Geology of Mount Pirongia and the Alexandra Volcanic Group’. It also signifies the end of four gruelling years of study on the mountain, hundreds of hours spent climbing, mapping and conducting detailed explorations of its rocks to unlock secrets that have long remained hidden.
Until Oliver began his study of Mt Pirongia, its geological history was largely unknown. While his work centred on Pirongia, he also examined its sister volcanoes making up the Alexandra Volcanic Group – Karioi, Kakepuku and Te Kawa; all are basaltic volcanoes that have unique characteristics in New Zealand.
That a comprehensive geological mapping of Pirongia has taken until now to do is largely because of the fact geologists have long been drawn to investigations of other volcanoes in the central North Island. Oliver said that had occurred primarily because the activity of those volcanoes warranted more pressing study, which in turn meant funding for the study of extinct volcanoes such as Pirongia was pushed to the back of the queue.
Having had to compete for funding to do the work, Oliver designed the project as ‘low-cost’. “I had a doctoral scholarship and applied for grants, then won a small grant from the Royal Society of New Zealand which covered aspects of fieldwork and lab costs. The main cost for me was time.”
The book is made up of 58 pages of text providing a detailed account of the geological history of Mt Pirongia from 2.6 million years ago to the present day, and has a full colour 1:30,000 map of the area. It acknowledges the support given by three academics whom he said made a ‘massive contribution’ to the work, Drs Adrian Pittari, Marco Brenna and Roger Briggs. Oliver described the publication as a ‘complete grassroots study’ aimed at producing a geological map that he hopes will remain relevant for 100 years and more.
Oliver completed his initial geology degree, then honours, at Otago University. He mapped Dunedin’s Karitane area, his first real attempt at geological mapping, then spent about six months studying the Xalapa volcanic field in Mexico before returning to New Zealand and embarking on his PhD.
The book launch at Pirongia Heritage Centre was as much about recognising those he collaborated with as it was about celebrating the place. A series of talks on the subject have seen him speak in Kawhia and Te Awamutu in recent weeks. He will talk at Hamilton’s Continuing Education, Reformed Church of Hukanui at 10am on December 1, and at Raglan Town Hall at 6.30pm on December 2.