White Bluff Formation
Geologic formation in Arkansas
From Wikipedia, the free encyclopedia
The White Bluff Formation is a marl, sand, and clay geologic formation in Arkansas that is part of the Jackson Group. It preserves fossils dating back to the Paleogene period, specifically the Eocene.
| White Bluff Formation | |
|---|---|
| Stratigraphic range: Paleogene | |
| Type | Formation |
| Unit of | Jackson Group |
| Sub-units | Pastoria Sand Member, Caney Point Marl Member, Rison Clay Member |
| Lithology | |
| Primary | marl, sand, clay |
| Location | |
| Region | Arkansas |
| Country | United States |
| Type section | |
| Named for | White Bluff, along the Arkansas River |
Description
The White Bluff Formation is composed of three members: the Pastoria Sand Member, the Caney Point Marl Member, and the Rison Clay Member.[1] The Pastoria Sand is a clayey sand containing glauconite and mollusca fossils. The Caney Point Marl is a chalky clay with glauconite and various invertebrate fossils. The Rison Clay is a clay with interbedded silts containing foraminifera fossils and scattered mollusca molds.[1] The entire formation was deposited as a marine sequence.[1][2]
