Golden Valley Formation
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| Golden Valley Formation | |
|---|---|
| Stratigraphic range: Late Paleocene-Early Eocene (Clarkforkian-Wasatchian) ~ | |
| Type | Geological formation |
| Sub-units | Bear Den & Camels Butte Members |
| Underlies | White River Group |
| Overlies | Sentinel Butte Formation |
| Thickness | up to 122 metres (400 ft)[1] |
| Lithology | |
| Primary | Claystone, mudstone, siltstone, sandstone |
| Other | Lignite, conglomerate |
| Location | |
| Coordinates | 48°30′N 102°42′W / 48.5°N 102.7°W |
| Approximate paleocoordinates | 52°54′N 82°12′W / 52.9°N 82.2°W |
| Region | North Dakota |
| Country | United States |
| Extent | Williston Basin |
| Type section | |
| Named for | Golden Valley, North Dakota |
| Named by | Benson & Laird[2] |
| Year defined | 1947 |
  Golden Valley Formation (the United States)  Golden Valley Formation (North Dakota) | |
The Golden Valley Formation is a stratigraphic unit of Late Paleocene to Early Eocene age in the Williston Basin of North Dakota.[3] It is present in western North Dakota and was named for the city of Golden Valley by W.E. Benson and W.M. Laird in 1947.[2] It preserves significant assemblages of fossil plants[3] and vertebrates,[4] as well as mollusk and insect fossils.[3][4]
The Golden Valley Formation was named in 1947.[2]
Between 1958–61, a large field expedition conducted by the Yale Peabody Museum recovered a plethora of crocodilian remains from the White Butte and Turtle Valley sites (collectively referred to as the South Heart Locality) within the Golden Valley Formation.[5][6]
Stratigraphy
The Golden Valley Formation is present as a series of outliers in western North Dakota.[7] It is underlain by the Sentinel Butte Formation and unconformably overlain by the White River Group.[1] It reaches thicknesses of up to 122 metres (400 ft) and is subdivided into two members: the Bear Den Member (lower) and the Camels Butte Member (upper).[1]
Lithologies
The base of the Bear Den Member consists of kaolinitic claystone, mudstone and sandstone that weather to white, light grey, orange, and purple.[1] These are overlain by grey or brownish carbonaceous sediments and, in some areas, a bed of lignite (the Alamo Bluff lignite).[3] In places the sequence is capped by a siliceous bed (the Taylor bed[3]) that represents a weathering surface or paleosol.[1] The Bear Den Member reaches a maximum thickness of about 15 metres (50 ft).[1]
The Camels Butte Member consists of montmorillonitic[3] and micaceous claystone, siltstone, lignite, poorly cemented sandstone and conglomerate.[1][3] The upper part includes a massive fluvial sandstone that caps many of the major buttes in southwestern North Dakota.[1] The Camels Butte Member reaches a maximum thickness of about 107 metres (350 ft).[1]
