For centuries the Green River has supported agriculture in the southwestern corner of Wyoming, but today the river is valuable for another reason: its natural resources.
The headwaters of the Green River at the foot of the Wyoming Rockies have provided agricultural success to ranchers farming hay and livestock along its banks since they settled here in the 19th century.
In recent years, however, the river basin has proven to hold an array of natural resources that are potentially as valuable as the abundant water has been to the farmers in this region.
Southwestern Wyoming is reported to hold the world’s largest deposits of trona ore; mining began in the early 20th century and is now one of the largest industries in the Green River Basin.
Trona is a mineral that can be refined into soda ash, which in turn is an important component in the manufacture of glass as well as many other chemical products.
The Green River trona was laid down between 50 and 60 million years ago when southwestern Wyoming was covered by a large shallow lake known as Lake Gosiute.
As the lake gradually dried up, trona and other minerals present in the water were left behind on the dry lake bed; over time, the trona was buried under layers of soil and sediment deposited by the Green River which began to flow across the region.
As well as depositing trona, the lake left behind layers of algae that had been present in the water and sunk to the lake bed when they died, continuing to build up in layers until the lake shrunk and disappeared.
As sediment piled up on top of the layers, huge pressures and high temperatures ‘cooked’ the trapped algae, turning it into oil which seeped into the porous rock, creating oil shale.
As a result, the Green River Basin is thought to contain the world’s largest deposit of fossil fuel: between 500 billion and 1.1 trillion barrels of oil are thought to be trapped in the rocks surrounding the Green River; three times the reserves of Saudi Arabia.