It wasn't. Two types of tar exist naturally: Petroleum tar and Pine tar.

No, tar sand is petroleum saturated sand deposits. It is a fossil fuel source like any other source of petroleum.

obtained from coal tar or petroleum

Asphalt (petroleum tar) mixed with gravel.

Tar is obtained from liquid petroleum. Tar is used as a hot liquid covering under gravel to build roads.

Note: Asphalt is made from bituminous coal pitch, mixed with sand or gravel. The black color comes from coal pitch, not from petroleum, as does tar.