The Age of Victoria’s Volcanoes

The 2016 A W Howitt Lecture


Dr Erin Matchan

Noble Gas Geochronologist
School of Earth Sciences, The University of Melbourne

Victoria is home to at least 400 short-lived basaltic volcanoes that erupted in geologically recent times (last 4.5 million years). These volcanoes, together with their eruptive products, form the ‘Newer Volcanic Province’ of southeastern Australia. The Newer Volcanic Province extends near-continuously from Melbourne, to the Mt Burr Range in South Australia. It contains the youngest volcanoes in Australia (e.g. Mt Gambier, Mt Napier, Tower Hill) and is still considered to be volcanically active, as the most recent eruptions took place within the last 10,000 years. This means that future eruptions are highly likely.

The eruption triggers, frequency, and styles of volcanism in the Newer Volcanic Province are the subject of active research in the geosciences community. Understanding the frequency of this volcanism has been impeded historically by difficulties in ‘dating’ basaltic volcanoes that are younger than one million years.  However, thanks to recent technological developments, geologists in the School of Earth Sciences at the University of Melbourne are pushing the limits of the ‘Argon-Argon (40Ar/39Ar)’ dating technique to precisely date lava flows as young as 30,000 years.  Using this method, they are unraveling the last million years of volcanic activity in Victoria.

Join Dr Erin Matchan to review the current understanding of the eruption history of the Newer Volcanic Province, and discover the different techniques that have been used to date the volcanoes. Dr Matchan will present some recently obtained, key 40Ar/39Ar dating results, focusing on volcanic eruptions that occurred within the last 500,000 years, and will explain how these data improve our understanding of eruption frequency.

About the Speaker:

Dr Erin Matchan is a research fellow in the Noble Gas Geochronology Research Group within the School of Earth Sciences, University of Melbourne. Her research primarily focuses on applying the Argon-Argon dating method to ‘very young’ (< 100,000 year old) volcanic rocks; no mean feat when this technique is usually used for dating rocks that are millions of years old! Although she has studied volcanoes in Iceland, Italy and the USA, she has dedicated the most time to studying the fascinating array of young volcanoes in Victoria.  Dr Matchan is interested in comparing Argon-Argon ages with those derived via complementary dating methods in order to inter-calibrate these different techniques. She is also interested in the potential implications these eruption ages have for better understanding the onset of human presence in Victoria, as well as eruption frequency in south-eastern Australia.