14 September 2017 at 7.30pm
Hawke’s Bay Regional Council, corner of Dalton and Vautier Streets, Napier
Professor, Geology Department, University of Otago, Dunedin, New Zealand
2017 Hochstetter Lecture
The landscape of New Zealand is spectacular in its expression of the active tectonic processes that occur along the Pacific-Australian plate boundary. However, it is difficult to determine the geological history of development of the onshore topography because previous configurations in the evolution of that topography have been eroded.
Some of the native fauna carry a biological memory of the topographic environments in which they evolved, in their genetic makeup (DNA). Native freshwater fish are the most useful for this type of study. In particular, the genus Galaxias has numerous freshwater-limited species and populations that have been isolated by changes in the river drainage pattern.
The South Island vividly displays the resultant biological diversity and co-evolution of topography and fish. The genetic variations of the fish can be used to document the nature and timing of river capture events and mountain range growth, especially since the Plio-Pleistocene but with some extensions into the Miocene. Hence, these biological tools provide some new insights into the development of the onshore landscape since the submergence or near- submergence of the NZ landmass in the Oligocene. The biological memory approach to understanding topographic evolution could be extended to all endemic NZ fauna and flora for which suitable distribution and genetic data are available.
Dave Craw is Professor of Economic Geology at the University of Otago where he has been on staff for 35 years. His main research interests are gold: exploration, mining and associated environmental issues, both placer and hard-rock. His particular interests in tectonic evolution of mountains and the gold within them led him to work on the biological effects of the rise of mountain ranges, the topic of the Hochstetter lecture.