2021 Penrose Medal

Presented to Ian W.D. Dalziel

Ian W.D. Dalziel

Ian W.D. Dalziel
Institute for Geophysics and Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin


Citation by John F. Dewey

President, Vice President, Fellows. It is my great honor and pleasure to introduce Professor Ian Dalziel as your 2021 Penrose Medallist. Ian is one of the great field-based geologists of our generation. He spent much of his childhood in the remote Scottish Highlands where he developed his love for wild places and instincts to explore. In the 1950s he attended the University of Edinburgh where GSA Penrose Medallist Arthur Holmes was Professor and continental drift considered a serious hypothesis. Ian is the established doyen and innovative global leader in mapping and elucidating the geological structure and history of the Southern Andes and West Antarctica. Working with international colleagues on land and shipboard, using geophysical techniques to map the ocean floor and measure tectonic motions, he has elucidated the tectonic history of the Scotia Sea and its borderlands and the 'collage' of continental blocks that form West Antarctica. His work has implications for the onset and development of the Antarctic Circumpolar Current, for migration of terrestrial and marine species and for the history and future of the least stable of our planet's ice sheets. In recognising late Precambrian rifting of the Transantarctic margin of the East Antarctic craton, he showed how this pointed to the identification of possible Antarctic continuations of the Laurentian Grenville orogen and mid-continent rift, playing a major role in the hypothesis that the Pacific margins of the Antarctic-South Autralian and Laurentian cratons were juxtaposed prior to opening of the Pacific Ocean. This first testable hypothesis of pre-Pangaea global paleogeography promoted a flood of new ideas, from scientists worldwide, concerning pre-Pangaea palaeogeography, the supercontinental cycle and the role of continental distribution in the global environment. He realized that the Andean margin of South America must be reconstructed against the Laurentian Appalachian-Caledonide margin in the latest Precambrian and was the first to recognize the constraints placed on the palaeogeography of Iapetus by the Cambro-Ordovician rocks of the Argentine Precordillera. Ian Dalziel is one of the world’s leading geologists who richly deserves the award of the Penrose Medal and further enhances the list of those who have received it.


Response by Ian W.D. Dalziel

Thank you, Professor Dewey, for those generous remarks. They mean all the more coming from a former Penrose Medallist whose work played such a vital role in elucidating the geologic significance of plate tectonics. As you note, I owe much to my Scottish heritage, both personal and geological. My parents took me to remote parts of the Highlands that awakened curiosity and wanderlust, the University of Edinburgh inspired global thinking as the legacy of Arthur Holmes. Moving to the US, the University of Wisconsin-Madison was an exciting place in the aftermath of Antarctic exploration during the International Geophysical Year. Robert H. Dott Jr. sparked my interest in the Scotia arc and that led Maurice Ewing to lure me to Columbia and the then Lamont-Doherty Geological Observatory just as plate tectonics was emerging.

Critical to furthering understanding of the southernmost Andes, the Scotia arc and West Antarctica were logistic support and international collaborators - not to forget a stream of enthusiastic and talented students and post-doctoral fellows. The logistic support came mainly from the Office of Polar Programs of the National Science Foundation, and in West Antarctica through cooperation with the British Antarctic Survey. This enabled my US group and its Argentine, British, Chilean and New Zealand colleagues to look 'over the horizon' to make geologic connections.

In the mid-1980s Art Maxwell, Director of the Institute for Geophysics of The University of Texas at Austin, now part of the Jackson School of Geosciences, offered me a position as essentially a full-time researcher. This enabled me in particular to work with my colleagues Larry Lawver and Lisa Gahagan of the PLATES project not only on enigmatic Pacific margin aspects of Gondwana reconstruction, but also on the pre-Pangea reconstructions that have generated so much productive research on the supercontinent cycle.

No work of this sort happens in a personal vacuum. The debt I owe to my former wife Linda Clark and our children Kacie and Kyle is incalculable. I can only trust the wonderful adventures we shared on several continents are some recompense for the times I was absent looking 'over the horizon'.