Hawke's Bay Branch event: 2017 Hochstetter Lecture

Tectonics and Genetics in topographic evolution

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 FRSNZ 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.

The Hochstetter Lecture is named in honour of Ferdinand von Hochstetter and a speaker is chosen annually by the Geoscience Society of New Zealand Awards Subcommittee. He or she gives a lecture at GSNZ branches during the year on recently completed and largely unpublished findings.

For a full list of dates and venues for the 2017 Hochstetter Lecture, see the Geoscience Society of New Zealand website.