Open-File Report 96-0729
Marly lacustrine rocks of the Eocene Green River Formation, which occupy parts of several basins in Wyoming, Colorado, and Utah, contain world-class resources of oil shale and sodium carbonate minerals. The formation contains the world's largest known resource of natural sodium carbonate as bedded trona (Na2CO3.NaHCO3.2H2O) in southwest Wyoming as well as the second largest known resource of sodium carbonate as bedded and nodular nahcolite (NaHCO3) in northwest Colorado. Five companies currently mine three beds of trona in Wyoming and one company mines a bed of nahcolite in Colorado.
Other sodium carbonate minerals in the Green River Formation that may have future economic potential include dawsonite (NaAl(OH)2CO3), eitelite (Na2CO3.MgCO3), and shortite (Na2CO3.2CaCO3). Several sodium carbonate brines in Utah and Wyoming may have economic value for soda ash and for water-soluble organic acids.
Posted August 1998