New Antarctic Map Decades In The Making

27 January 2014

A new geological map of southern Victoria Land in Antarctica shows the area in more detail than ever before.

Covering 84,600sq km, including the largest ice-free area of Antarctica, it replaces a 1962 map generated by New Zealand geologists Bernie Gunn and Guyon Warren.

It features the area between Ross Island and the Polar Plateau, in a region where New Zealand earth scientists have made their largest contribution to Antarctica.

Published by GNS Science, it is the twenty-second and last in a series of major regional geological maps at 1:250,000 scale. The maps, called the QMap series, have been produced at a rate of about one a year since 1995 and now completely cover New Zealand.

The southern Victoria Land map has involved a compilation of information from about 500 scientific papers and 190 maps, some dating back nearly a century. In addition, geologists undertook new fieldwork and studied satellite data and aerial photos in areas that were poorly known. More than a dozen external reviewers also provided input.

Lead author, Simon Cox of GNS Science, said that “the map is arguably the most comprehensive digital geological map of a defined area of Antarctica.”

Fieldwork for the earlier 1962 map was undertaken during the 1957-58 International Geophysical Year. Geologists undertook fieldwork for the new map in 2007 - 50 years later – as part of the International Polar Year collaborations.

A large number of people and organisations have contributed to the map, including the GNS Science mapping team and Antarctica New Zealand.

“It was so desperately needed! The previous edition was woefully out of date and only in hardcopy format. Those who initiated the project had complete conviction that it would be useful and will become highly valuable,” said Dr Simon Cox, a Principal Scientist.

The new map contains much more detail – about 195 different rock and ground classifications compared to 15 such groupings in the earlier version.

Dr Cox said that the Gunn and Warren map has been a standard geological reference for decades and one of the most highly cited pieces of Antarctic literature.

“Our mapping team remain in awe of the achievement of Bernie Gunn and Guyon Warren. Theirs was a remarkable contribution to Antarctic science, but we have now taken a giant leap forward.”

In the 1950s Gunn and Warren undertook a 1500km-long dog-sled journey with limited external support. In contrast, in 2007 geologists benefitted from helicopters as well as satellite data, aerial photographs, and much more logistic support.

The previous geological map had little information on glacial deposits and glacial history. This is now the focus of many projects aimed at understanding the degree and impacts of climate change. The map also puts glacial deposits into regional context, which is extremely useful for understanding past ice fluctuations in response to climate change.

“The new map is a great improvement and will provide a solid baseline for a variety of geological and biological science,” Dr Cox said.

“The data from this map are already being used by scientists in New Zealand and overseas.”

The large full-colour 1:250,000-scale map is tucked into a sleeve in the back cover of a 135-page companion book. Titled Geology of southern Victoria Land, Antarctica, the book includes stunning colour photographs of the Antarctic landscapes, a large number of illustrations, and numerous diagrams summarising aspects of the geology.

The book is divided by stratigraphy (rock layers of different ages) and contains information about all the geological formations spanning the Precambrian to the Holocene, including a lexicon of geological units shown on the map.

In his foreword in the book, prominent Antarctic scientist Peter Barrett, of Victoria University, describes the map as a masterpiece of clarity and detail considering it covers such a large area and represents more than 200 different rock units.

“It will have value both on the walls or tables for big-picture conversations, or enlarged segments for specific projects,” Professor Barrett said.

The map and its accompanying text took six years to complete. The fieldwork was completed in a five week period in 2007 and involved two teams of four geologists.

Dr Cox said by far the hardest part was having the stamina to complete the job in the office.

"The fieldwork had its moments of physical hardship, but it was mentally demanding to be on top of all the aspects of Antarctic geology. Walking across a glacier full of hidden crevasses in a condition 1 or 2 storm is relatively straight forward by comparison,” he said.

The production was mostly carried out in GNS Science's Dunedin office, where Simon Cox, Ian Turnbull and Belinda Smith-Lyttle are based. In addition, specialist help was given by fellow geologists Michael Isaac, Dougal Townsend, Mark Rattenbury, Richard Jongens, and Adam Martin.

The mapping of Antarctica is by no means finished for GNS Science. Geologists are now working towards a map that shows a much larger area of the Transantarctic Mountains. This will be a 1:2 million scale map and will be available in 2018.

All geological data used to make the southern Victoria Land map is held in a Geographic Information System, available in digital format on request.

Additionally, the digital geological map information can be viewed and interrogated through the international OneGeology web map portal. The map and text are available from GNS Science for $35 plus postage.

ENDS

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