[1] The Precambrian basement rocks in the center of the basin beneath the city of Williston, North Dakota lie about 16,000 feet (4,900 m) below the surface.
Near the end of the Cretaceous, tectonic activity during the Laramide Orogeny rejuvenated several basement structures in the Williston Basin to produce anticlines that serve as oil traps today.
After four years of testing and mapping they started drilling at a promising lease 30 miles north-east of Williston, North Dakota, and on April 4, 1951, discovered oil on the Nesson Anticline, with the Amerada Hess Corporation Clarence Iverson #1 well.
The Williston Basin holds large coal deposits, primarily in the Fort Union Formation of mostly Paleogene age, and were first noted during the Lewis and Clark Expedition.
The helium originated through natural radioactive decay of uranium and thorium in Precambrian granitic basement rocks, or Lower Paleozoic shales.
The Deadwood is characterized by shallow marine and coastal plain sediments, with abundant glauconite giving the formation a distinctive green color.
The basin started subsiding due to strike-slip movement along northeast–southwest trending faults, resulting in the deposition of the Winnipeg Group, which lies unconformably on the Deadwood.
The Red River Formation lies unconformably on the Winnipeg, and consists of shallow marine carbonate, anhydrite, and salt sedimentation.
The overlying Minnelusa Formation is characterized by deposition in alluvial plains, prograding river delta, and barrier island environments.