Another possibility for the rise of the Looney vs Greenback:
Canada had a federal budget released today. Any one interested in it's contents may view at:  www.budget.gc.ca

Yes, I especially recommend a look for you Yanks, compare to your budgets, not the numbers but what is or is not done and how. This budget is released by a conservative govermnent ( to which I often refer to as a clone of the one in Washington right now ) but not too bad, imo. Whould you not want that kind of budget for yourself?
Think about it the next time you vote in a primary or in the real thing later.

Getting back to the loony.
I suspect US dollars getting a hint of what the budget might be, decided to trade in for the looney and invest in some canadian resources. Hence the changes in prices.