20 June 2008
After our trip to Great Sand Dunes National Park, where we compared dunes on Earth to those on Mars, we flew up north to Winnipeg, Canada. There we met up with a bunch of geologists and spent three days exploring a bunch of interesting sites in Manitoba.
The first site was an old mine tailings dump from a gold mine in the area. When mining for gold, the rocks are typically pulverized into a fine powder and mixed with cyanide. The cyanide dissolves the gold, which can then be separated out, but the gold is only a tiny fraction of the rocks, so there are thousands of tons of cyanide-rich sludge called “tailings” that get dumped near the mine. Here’s what it looks like coming fresh out of a mine, rich with sulfur compounds and cyanide and pouring into a former lake:
The site we went to was an old tailings dump where, due to the rocks being ground to a fine powder, chemical reactions had happened much faster than normal. The whole area was bright orange from iron oxides which form as the tailings are oxidized.
It was also cris-crossed by milky blue streams carrying copper sulfate and sulfuric acid.
This site was interesting because many of the minerals forming there, such as sulfates and iron oxides, might also form on Mars. Many experts also suspect that water on Mars might have been very acidic, especially if it had a lot of sulfur in its early atmosphere.
To me the site was also a fascinating and scary look at the lengths people go to just to extract some shiny metal from the ground.
Stay tuned for more cool pictures from our Great Canadian Adventure!