"Tar sands" refers to a type of oil deposit found in sandy or clay-like materials. The term is used to describe these deposits because they contain a sticky and thick form of petroleum called bitumen, which is similar to tar. Full definition
To produce one barrel of tar sands oil requires about three barrels of water. (treehugger.com)
All things considered, the energy you can get from burning a barrel of tar sands oil only barely exceeds the energy required to produce it. (resilience.org)
First, producing oil from tar sands emits two to three times the global warming pollution of conventional oil. (dirtyoilsands.org)