Tar sand. Swamp-like deposit of a mixture of fine clay, sand, water, and variable amounts of tar-like heavy oil known as bitumen. Bitumen can be extracted from tar sand by heating. It can then be purified and upgraded to synthetic crude oil.
Bitumen. Gooey, black, high-sulfur, heavy oil extracted from tar sand and then upgraded to synthetic fuel oil.
(Source: UNFCCC2009 website glossary.)
There wasn't much coverage of the 2009 UN Climate Change Conference in the Canadian media - there were some vague hints that Canada isn't exactly on the side of the angels because of the tar sands, and then things fell strangely quiet.