Working to discover how events millions of years ago may be affecting us today is no easy feat.
But Eckart Buhlmann, an exploration geologist and instructor at Flin Flon’s Northern Manitoba Mining Academy, and colleagues are peeling back the layers of history to answer a key question about the Flin Flon-Snow Lake region’s mineral riches.
Buhlmann has pondered how the region’s copper, zinc and gold deposits came into existence and, more specifically, where the metals and the energy needed to create them, came from.
“A good answer to this question will open the way to new ore discoveries,” he says.
Buhlmann’s research is focusing on the potential role of meteorite impacts. Rare and unpredictable meteorite impacts can readily provide the energy and heat needed to extract metals from may tens of cubic kilometres of basalt and convert the product into ore bodies.
“To make one tonne of copper we need one 40-tonne truck load of high-grade copper ore,” says Buhlmann. “But to make one truckload of high-grade ore, nature had to process at least 400 truckloads of ordinary country rock. How can this be accomplished?
“We are getting a little closer to an answer and this is so important because it holds a key to making large high-grade ore discoveries in the future.”
Buhlmann says ore bodies in the region occur in patterns. The Flin Flon, Sherridon, Reed and Snow Lake ore bodies form clusters that happen to fit into a 160-km-diametre circle that centres on Elbow Lake halfway between Flin Flon and Snow Lake.
The ages of the rocks close to these ore bodies are similar, Buhlmann says, and all deposits that return positive assay results are associated with one of three types of rhyolite, a type of volcanic rock, and ferrogabbro, a dark rock with high iron and titanium content.
Looking at the main part of Elbow Lake, one can make out a vague circular pattern arranged by islands and tips of peninsulas. On the ground, one encounters a lot of sheared, stressed rocks.
Buhlmann says drill cores from past drilling returned iridium anomalies, but they were not strong enough to prove there was a meteorite impact.
Still, the working hypothesis remains in place: an impact event may have happened in the past.
What makes this hypothesis attractive, Buhlmann says, is that the impact would instantaneously supply the energy needed to drive the ore-forming process.
Based on further research, he takes seriously the hypothesis that the Kisseynew basin – a geological term for the 200-by-400-km region extending between Sherridon and Lynn Lake – is the central remnant of a meteorite impact structure, much larger than the possible Elbow Lake structure.
This structure would include the Fox Lake and Ruttan mines in the Lynn Lake and Leaf Rapids volcanic belts, the Hanson Lake block and the Flin Flon-Snow Lake volcanic belts.
