The term "tar sands" refers to a type of petroleum deposit that is found primarily in Canada. These deposits are composed of sand or clay that contains a thick, sticky form of crude oil called bitumen. The extraction process for tar sands involves strip mining the land and then using heat and steam to separate the bitumen from the soil. Due to the high energy consumption required in this process, it has been criticized as being environmentally damaging and a significant contributor to greenhouse gas emissions.