Hochstetter Lecture 2005
The 2005 Hochstetter Lecture will be given by Dr Jamie Shulmeister (University of Canterbury) at GSNZ branches and other venues in June and July. The subject of his lecture will be
Warming up the last glaciation in New Zealand
Climate forcing in New Zealand since the Last Glacial Maximum: a view from the South
Jamie Shulmeister collecting cosmogenic samples in the Rakaia Valley, New Zealand
Jamie researches terrestrial paleoclimates focusing on the Pacific Basin, especially New Zealand, Australia and Antarctica. He undertakes geologically and ecologically based investigations of glacial and coastal systems and studies lake records. He is heavily involved in international paleoclimate research through the Past Global Changes programme (PAGES) and is a member of the INQUA (International Union for Quaternary Research) paleoclimate commission and the co-leader of an INQUA paleoclimate project focusing on Australasia. He graduated from Trinity College Dublin in 1984. He gained his MSc from Queen's University in Canada and his PhD at Australian National University in 1991. Since then he has been a Post-Doctoral Fellow at the University of Canterbury, a visiting Assistant Professor at the University of Southern California, and a lecturer at Victoria University of Wellington before returning to the University of Canterbury, where he is currently an Associate Professor in Quaternary Geology. Abstracts
Hochstetter Lecture: Warming up the last glaciation
Over the last several decades there has been international interest in the relationship between New Zealand glacier advances and global ice ages.This is because of the apparently synchronous response of New Zealand glaciers to Northern Hemisphere cooling which makes New Zealand a key place to understand global climate linkages. Large parts of Europe and North America quite literally froze solid during the last ice age. However, while glaciers expanded greatly in New Zealand during the glaciations there has never been strong evidence for a really significant cooling.The main indicator of serious cooling is the apparent exclusion of forest cover from most of the country south of Auckland during the last glacial maximum but this observation has always been inconsistent with the relatively minor cooling inferred (4-6C) from other techniques. Extreme climate events (e.g. killing frosts) rather than regional cooling are usually invoked to explain these data.
Here I will summarise the story from recent sedimentological, chronological and paleontological studies which together give a new insight into how ice ages work in New Zealand. I will demonstrate that ice advances were abrupt, rapid and probably of short duration. I will show how, at least locally, non-glacial conditions persisted during glacial times, even in close proximity to the glaciers themselves. Finally, I will present my thoughts on vegetation reorganization and present an alternative hypothesis to global cooling as the main forcer for New Zealand glaciers.
Supporting lecture: Climate forcing in New Zealand since the Last Glacial Maximum: a view from the South.
Geologically recent climate change in the New Zealand region is now the focus of much research, especially with the start of the Australasian INTIMATE (INTegration of Ice-core, Marine And TErrestrial records) project.While there has been a long standing interest in how New Zealand climate systems respond to forcing from the North Atlantic, there has been less focus on the role of the Southern Ocean and virtually none on tropical forcing. I will argue that climate change in the New Zealand region since the Last Glacial Maximum has largely responded to tropical and Southern Ocean changes. I will focus on three major climate transitions; (i) For the termination of the last glaciation it is clear that it occurred much earlier in New Zealand than in the Northern Hemisphere.Is deglaciation in New Zealand triggered from Antarctica or does deglaciation start elsewhere?(ii) A number of abrupt climate events (Antarctic Cold Reversal, Younger Dryas etc) have been proposed for the latter part of the last deglaciation. Which of them are manifested in the New Zealand region and what caused them?(iii)There is a possible climate event in the early Holocene and a major climate transition in the mid-Holocene.What are they and what caused them? In all cases, I will highlight the evidence for links to the tropics and South America. I will also highlight the role of Walker Circulation in controlling New Zealand climate change, through ENSO and regional wind fields.
About Hochstetter by Mike Johnston
Christian Gottlieb Ferdinand von Hochstetter (1829-1884)
Hochstetter was born in Esslingen in the Kingdom of Wurttemberg and joined the Austrian Geological Survey in 1853. Four years later he was appointed geologist on the Austrian frigate Novara that undertook a global scientific cruise. The Novara berthed in Auckland, then the capital of New Zealand, on 22 December 1858. At the request of the New Zealand Government and supported by the Auckland Provincial Council, Hochstetter, accompanied by Julius Haast and others, surveyed the Drury Coal Field to the south of the capital.
This was accomplished so successfully that the provincial council persuaded the commander of the Novara to allow Hochstetter to remain in New Zealand so that he could undertake further work in the province. Over the next five months Hochstetter and Haast, and a support team, visited much of southern part of Auckland Province, including the volcanic region and the gold diggings at Coromandel Harbour.
On completion of his Auckland mapping, Hochstetter was commissioned by the Nelson Provincial Council to report on the mineral wealth of the province. Hochstetter, accompanied by Haast, arrived in Nelson, after brief stops at New Plymouth and Wellington, on 4 August 1859. In Nelson, they examined Dun Mountain, and from which he collected and subsequently named dunite, the Aorere Gold Field and other places of interest. While Hochstetter visited the Wangapeka Gold Field in the west and Lake Roto-it, Haast geologically examined the eastern part of the province . Hochstetter left Nelson for Sydney on 1 October 1859, on the first leg of his return voyage to Europe.
His geological maps of Auckland and Nelson were the first of their kind in New Zealand.