Sally Pehrsson - Geology

Sally Pehrsson

Name: Sally Pehrsson
Field of Expertise: Structural Geology/Precambrian Tectonics
Education: Ph.D. in Geology, Queen’s University
Works at: Natural Resources Canada’s Geological Survey of Canada in Ottawa, Ontario

What she studies

Dr. Pehrsson studies the formation of the world’s first global supercontinent over 2 billion years ago and its effect on mineral deposits found in the Canadian Precambrian shield. She works on shield rocks in Nunavut, Northwest Territories and the Prairie provinces, studying the ancient mountain ranges and mineral deposits that formed during the supercontinent’s assembly.  Using field observations, radiogenic isotopes and micro-scale composition of minerals, she investigates the age and deformation history of the mountain ranges and how they continued onto other parts of the original supercontinent.

What is the importance of her research?

The Canadian shield is one piece in an ancient Precambrian puzzle that was broken apart over 1 billion years ago.  By studying the history of the Canadian piece we can test and evaluate where it fits in the puzzle and what happened outside our preserved piece.  This knowledge will help us understand what mineral deposits could be found in central and northern Canada, because important clues to the ancient mineralizing processes now lie in originally attached parts of Australia, Siberia and North China.  Understanding the puzzle and its mineral potential helps industry explore more effectively and bring economic benefit to resource-dependant areas.

Interesting fact

The ancient submarine island arc rocks that formed during closure of the supercontinent are now found in West Africa, Fennoscandia, Australia, central northern Canada and the southwest United States. These rocks contain more tonnes of Copper-Lead-Zinc (Cu-Pb-Zn) per square kilometre than any other metavolcanic rocks on Earth and economically support more than 35 northern communities in Canada alone.

Current research projects

Paleogeographic reconstructions from 2.5-1.4  Billion years ago.  Secular change in volcanic-hosted massive sulphide deposits, influence of accretion style and tectonic setting on ore deposit preservation in NRCan’s Targeted Geoscience Initiative-IV and Geoscience for Energy and Minerals programs.

Key publications

Helmstaedt, H. H. and Pehrsson, S.J.  in press.  The Slave Province.  Geological Society of America Bulletin, 281p.

David L. Huston, Sally Pehrsson, Bruce M. Eglington, and Khin Zaw.  The Geology and Metallogeny of Volcanic-Hosted Massive Sulfide Deposits: Variations through Geologic Time and with Tectonic Setting.  Economic Geology, May 2010; 105: 571 - 591.

D.  Corrigan, S. Pehrsson, N. Wodicka, and E. de Kemp.  The Palaeoproterozoic Trans-Hudson Orogen; a prototype of modern accretionary processes (in Ancient orogens and modern analogues) Geological Society Special Publications (2009), 327 457-479.

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