Many riches underlie Canadian Prairies – by Lesley Stokes (Northern Miner – November 8, 2016)

VANCOUVER — There’s more than meets the eye when it comes to mineral potential in the Canadian Prairie provinces of Manitoba, Saskatchewan and Alberta. Their unique — and often overlooked — geological heritage has fostered a variety of world-class metal districts, and some of the last frontiers for mineral exploration in the country.

Three cratons of the Canadian Shield underpin the Canadian Prairies: the Archean-aged Superior terrane in the east, slightly younger cratons called the Hearne and Rae in the northwest, and remnants of the Paleoproterozoic-aged Trans-Hudson Orogen sandwiched in-between.

The terranes, each largely composed of greenstone belts, were sutured together 1.9 billion years ago during the assembly of ancestral North America. At the time, the Trans-Hudson Orogen was a vast mountain chain that has since eroded down to its core.

The Paleozoic sedimentary rocks that cover the rest of Manitoba and Saskatchewan pale in comparison to the sediments over much of Alberta. Erosion off the neighbouring Canadian Rockies for the past 170 million years — coupled with deposition from ancient seas — has buried the Canadian Shield with sediments up to 5 km thick.

Even to this day, the deep burial transforms any organic layers into oil, which is then moved along with vast groundwater brines for hundreds of kilometres before being caught in impervious traps.

In northern Alberta, extremely permeable quartz-rich sand — sourced from a Ganges-sized river system that spanned Canada 90 million years ago — eventually became today’s prolific oil sands deposits, which are the third-largest oil reserve on the planet.

For the rest of this article, click here: