Base Metals in the Snow
by Phil Brown
The day after graduation, Monday May 18, 2009, a hardy group of 11 undergraduates, one graduate student and I left for Manitoba as the reward for sitting through a semester of my Economic Geology class (G515). Most of us travelled in a small 14 passenger “bus” reserved from Car Fleet but as this has no storage space, we also took along “Garnet”—one of the aging department 15-passenger vans that has had all the bench seats removed turning it into a trailer with a motor.
Our destinations for the trip were the famous mining areas of Thompson and Flin Flon, Manitoba.
Day one ended with us camping in downtown Grand Forks, North Dakota. The campground occupies the flood plain of the Red River and it is a bit surreal to be camping on the grassed areas where, until the great flood of 1997, houses stood. The curbs and sidewalks are still largely present, as are the streets. The ambiance of a campground was lacking but partially made up for by having a choice of licensed establishments on the edge of the flood plain. The following morning began a long day’s drive north, north, north to Paint Lake Provincial Park a half-hour south of Thompson, Manitoba.
I had promised the students that we would likely be watching the ice melt in the lakes during our trip but we got off to a poor start on this—Paint Lake was frozen solid and there was snow on the ground and we were likely the first campers of the year.
The next morning we were due in Thompson early to have a mine tour hosted by Vale-Inco at their underground mine. We awoke to several additional inches of heavy wet snow and there were a few anxious moments as we wondered whether our 14-passenger “short bus” was going to climb the hill out of the campsite. Thompson is one of the most famous nickel mining areas of the world with the nickel sulfides occurring in mafic and ultramafic rocks comprising part of a very complicated package of rocks marking the boundary of the Archean Superior province with the Proterozoic Churchill province. Deformation here was broadly contemporaneous with the Penokean Orogeny that formed much of the Precambrian basement of Wisconsin. Vale-Inco gave us a nice underground tour, followed by a welcome (indoor) lunch and talk. The weather was too poor for us to have an organized surface trip that afternoon so we returned to our very white camp and ended the day with a fire on the rocky beach of frozen Paint Lake.
Thursday morning we headed west across the Province to Flin Flon, the city lies astride the Saskatchewan border. We camped for three nights just SE of the city at the beautiful Baker’s Narrows Provincial Park where there was actually liquid water on the surface of the lake! Hudson Bay Mining and Smelting was our host for two exciting days examining the massive sulfide ores and their host rocks both underground in the Triple 7 mine and in surface outcrops. Rather more relaxed environmental regulations (i.e., none) in the past led to clear cutting of timber for the mines, extreme acid rain killing the rest of the vegetation, and then denudation of the thin soil typical of the Canadian shield. This triple threat attack has yielded dozens of acres of naked rock that provide the finest study area in the world for examining Proterozoic pillow lavas, lava tubes and crosscutting feeder dikes. Sunday morning we loaded up our “land yacht” and trusty “trailer van” and headed back south in search of spring which was only a rumor in Thompson and Flin Flon. We made it all the way to Rushing River PP in Ontario’s Quetico just a bit north of International Falls. The river was running high but the high point of this campground was I believe the showers.
The following day we tried a little road geology on both sides of the border but our field guides were 10-15 years old and most of the road cuts were obscured by lichen, underbrush and hundreds of saplings; we gave up and returned to Madison. Before big international field trips in the past the Ontario Geological Survey would send seasonal workers out with pressure washers, bleach and scrub brushes to make the outcrops presentable. Thus many of the published outcrop photographs provide misleading views of what you will find today. The high point of the geology on this day was looking at the Archean-aged Banded Iron Formation outcrops of the Vermillion Range. All of us had a tremendous time and learned a lot of geology.
This trip was made possible by those generous donations that have established the Student Field Experience Fund—both the students and I are grateful for the opportunity.
Originally published in The Outcrop for 2009, UW-Madison Department of Geoscience, p. 19.