Simulating the source waters for the Wilkins Peak Member evaporite sequence with modern soda spring analogues

Chemical sediments of the lacustrine Wilkins Peak Member of the Eocene Green River Formation potentially preserve detailed paleoclimate information relating to the conditions of their formation and preservation within the lake basin during the Early Eocene Climatic Optimum. The Green River Formation comprises the world's largest sodium-carbonate evaporite deposit in the form of trona (Na2CO3⋅NaHCO3⋅2H2O) in the Bridger Basin and nahcolite (NaHCO3) in the neighboring Piceance Creek Basin. Modern analogues suggest that these minerals necessitate the existence of an alkaline source water. Detrital provenance geochronometers suggest that the most likely source for volcanic waters to the Greater Green River Basin is the Colorado Mineral Belt, connected to the basin via the Aspen paleoriver.