The Three Forks Group is a stratigraphical unit of Famennian age in the Williston Basin. It takes the name from the city of Three Forks, Montana, and was first described in outcrop near the city by A.C. Peale in 1893 (for the Three Forks Shale).

2018年11月21日 · Named after the city of Three Forks, Montana, the Three Forks Group is a stratigraphic unit in the Williston Basin. Below the surface the Three Forks is referred to as the Three Forks Formation, and lies below the Bakken Formation and above the Birdbear Formation.

The Three Forks Group is a stratigraphical unit of Famennian age in the Williston Basin.

In Saskatchewan, the Three Forks Group comprises the Torquay, Big Valley, and Bakken formations. Torquay and Bakken strata are present over much of southeastern Saskatchewan, while the Big Valley is present in only part of the region.

Lewis and the main party made camp on July 26 about seven miles down river from the Three Forks. The next morning, July 27, while continuing upstream, Lewis noted: . . . the river was again closely hemned in by high Clifts of a solid limestone rock which appears to have tumbled or sunk in the same manner as those discribed yesterday.

Peale (1893, p. 29) introduced the term "Three Forks Shale" for argillaceous and calcareous strata sandwiched between Mississippian and Devonian carbonates in southern Montana. Haynes (1916) described similar strata as the Three Forks Formation.

The Bakken Formation unconformably overlies the eroded Upper Devonian Big Valley and Torquay formations of the Three Forks Group. It is conformably overlain by the Mississippian carbonates of the Souris Valley (Lodgepole) Formation (Smith and Bustin, 2000).

2023年12月9日 · The Three Forks Group is a stratigraphical unit of Famennian age in the Williston Basin. It takes the name from the city of Three Forks, Montana, and was first described in outcrop near the city by A.C. Peale in 1893 (for the Three Forks Shale). The Three Forks Group is composed of dolomite, mudston

The Three Forks Group is a stratigraphical unit of Famennian age in the Williston Basin. It takes the name from the city of Three Forks, Montana, and was first described in outcrop near the city by A.C. Peale in 1893 (for the Three Forks Shale).

The Three Forks Group is a stratigraphical unit of the Famennian age in Montana, USA. The Famennian age was the last age/stage of the late Devonian, during the time that the first tetrapods appeared in the seas. Major minerals found …