Two regions; two new stories for NWT kimberlite.
More than a half-century ago, R.G. Blackadar and R.L. Christie unwittingly kicked off the hunt for diamonds in Canada’s North.
The two geologists mapped a basic intrusive on Somerset Island, Nunavut in 1963, - a full decade before the release of the landmark paper “Kimberlite from Somerset Island” by Roger Mitchell and P. Fritz in 1973.
That was the paper that fixed the gaze of diamond giant De Beers on Canada’s North in the earliest push for North American diamond exploration.
Explorers from De Beers and the many juniors who followed began at the Peuyuk kimberlite at Somerset, snaked west to the Mackenzie Delta, then down the Mackenzie River to Fort Simpson in the NWT’s Dehcho region, finally swinging east to Lac de Gras where the best-known story began with Stu Blusson and Chuck Fipke’s staking victory, and continues today with advanced exploration by the likes of Kennady Diamonds.
But what if something was missed along the way? Recent research suggests there may be some new stories to follow in NWT diamond exploration.
Reaching into a Haystack, Finding the Needle
The first story lies in the Central Dehcho region.
As the last major area of exploration before attention turned to Lac de Gras, the potential of the Dehcho region was deemed unworthy of much fuss.
But in 2003, Olivut Resources drilled in the region and struck kimberlite. Upon analysis, the junior reported finding two diamondiferous kimberlite pipes.
While these two pipes ultimately proved uneconomical, it marked the beginning of renewed scientific interest in the region.
The Northwest Territories Geological Survey (NTGS), a division of the Government of the Northwest Territories, was tasked with building knowledge of the geology of the region.
“We did fieldwork in 2003, 2005 and 2008 to get a better idea of the area’s mineral potential,” explains Scott Cairns, Manager of Mineral Deposits and Bedrock Mapping. “We took stream sediment and till samples from the area and spent some time analyzing the samples.”
The results were promising, with many indicator minerals pointing to the presence of kimberlite and then, shockingly, an intact diamond.
“First off, the discovery of a diamond in this kind of testing is incredibly rare,” says Barrett Elliott, Diamond Geologist with NTGS. “It’s like finding the eye of a needle in a haystack. The region was mostly unexplored and we were basically testing areas to build some baseline knowledge in support of land use questions.”
On the more conventional end, Cairns and Elliott worked with University of Alberta Ph.D candidate Stephane Poitras, a student of Dr. Graham Pearson, the Canada Excellence Research Chair in Arctic Resources. Poitras handled the microanalysis necessary to characterize the indicator minerals.
The findings were striking, with almost all analyzed minerals plotting within a relatively low temperature range that favors the presence of diamonds in kimberlite bodies.
“Old and cold,” Cairns quips. “That’s what you look for in your indicator minerals if you want to find diamonds. Otherwise they’ll have just changed to graphite.”
Lac de Gras Redux?
The findings were compared with testing done in the Lac de Gras area directly downstream from the diamond mines that put the NWT on the map and the heart of the famed Slave Geological Province.
“The kimberlite indicator minerals found in the Central Dehcho are as supportive of economic kimberlites as those in the Lac de Gras area,” Elliot says. “It’s particularly impressive when you consider that we’re comparing what’s essentially a blind test with an area driving the fifth highest annual diamond production worldwide.”
Stefan Poitras’ research is ongoing, with other results expected to be announced at the International Kimberlite Conference in 2017.
Perhaps as exciting as the geology is the comparative accessibility of the region. “Some of our samples were collected only a few hundred yards from the [all-season] highway,” Cairns says. “As any explorer knows, public road access can cut costs in big ways.”
While there is still work to be done, the newly-advanced scientific knowledge, positive preliminary results and stunning find of an intact diamond all point to good things in the Central Dehcho.
Kimberlite in the Far North?
Farther north, Banks Island is another NWT area that may have been overlooked.
The remote island is part of Canada’s Arctic Archipelago in the Beaufort Sea. Muskoxen outnumber people by a factor of more than 600.
Studies by the Geological Survey of Canada suggest there could be a kimberlite field on the island.
“They were able to recover kimberlite indicator minerals in their samples,” Cairns says, “and the results are, once again, quite promising.”
Old and Cold
While the process is in early stages, this Geo-mapping for Energy and Minerals (GEM) initiative of Natural Resources Canada potentially points to an undiscovered, geographically unique kimberlite field on Banks or western Victoria Island.
Preliminary data collected from a network of teleseismic stations (measuring natural earthquake activity) by Dr. Pascal Audet and Dr. Andrew Schaeffer from Carleton University, in partnership with the NTGS, suggests that the right geological conditions for creating diamonds may exist deep in the earth beneath Banks Island. Although more work remains to be done, this is indeed promising for diamond exploration in the region.
“The work is definitely in early stages,” Cairns says, “but any new kimberlite field could mean new opportunities for savvy explorers.”
It would be a unique stake in a small location with little space for competition and an established airport; all positive for explorers looking for the next big find in Canada’s North.