107Multidimensional Challenges to Human Sustainability
3.7.6 Tar Sands
Tar sands are also referred to as bituminous or oil sands. Major deposits are
found in the United States in eastern Utah [reserves estimated to be between
1.43 × 10
9
and 2.27 × 10
9
m
3
(Tar Sands 2011)], and great quantities are present
in east central Alberta in Canada (about 2.09 × 10
11
m
3
). The Alberta tar sand
deposits contain about 85% of the world’s known reserves of natural bitu-
men (Titman 2010; Veazey 2006). There are also large deposits of tar sands in
Venezuela (about 3.18 × 10
10
m
3
of recoverable reserves in the whole Orinoco
belt, assuming 22% recovery) (Cleveland and Roman 2007). A web report
by the USGS (2009) reported that their estimate of technically ...