Bioherms in the Great Salt Lake
Great Salt Lake is a modern hypersaline lake and a remnant of freshwater Pleistocene Lake Bonneville. It serves as a modern analogue to the Uinta Basin’s lacustrine Green River Formation and lacustrine microbial formations worldwide, including several recent very large oil discoveries in the deepwater offshore Brazil (pre-salt Santos Basin and others). Actively forming microbial stromatolites, pustular thrombolites, and tufa deposits are found within the lake and along its shores. Beaches and nearby dunes consist of abundant associated hypersaline ooids, coated grains, peloids, and rip-up clasts.
Recently, a few geologists from the UGS traveled to Antelope Island in the Great Salt Lake to investigate the modern microbial carbonates (i.e., bioherms) first hand. The most convenient place to see the bioherms is in Bridger Bay on the northwest side of the island. The bioherms live in roughly 1 to 3 feet of water, of course this will depend on overall lake level elevation. Now is a good time to see these unique structures as the lake level is quite low.
Geologists from around the world have traveled to Utah to see these modern bioherms and relate their depositional environment back to ancient examples that now serve as excellent oil reservoirs.