- Usage in publication:
-
- Poe evaporite member
- Modifications:
-
- Named
- Dominant lithology:
-
- Evaporite
- Salt
- Anhydrite
- Gypsum
- AAPG geologic province:
-
- Williston basin
Summary:
Named the basal member of Nesson formation (new). Type section in interval 6,947 to 7,065 ft in Phillips-Skelly-Gulf No. 1 Hoehn (Poe Unit) well, center NE1/4 SE1/4 sec 13, T152N, R102W, McKenzie Co, ND in the Williston basin. Underlies Picard shale member (new); unconformably overlies Triassic? Spearfish formation. In type section, consists of basal 65-ft bed of massive salt overlain by 53 ft of white to pink gypsum and anhydrite and dark-red shale with a few thin interbeds of gray to red, dense dolomite; thin bed of buff to brown very finely crystalline to earthy limestone present at top. Eastward, the Poe member contains much massive anhydrite on the east flank of the basin; westward it is characterized by development of much interbedded red shale and claystone. Thins westward from type well and appears to merge in Bowdoin dome area with younger members of formation. Exhibits rapid thickness changes on east flank of Williston basin where member overlaps Spearfish formation and Madison limestone and rests on pre-Mississippian sediments. Rocks assigned to Gypsum Spring formation in the Black Hills have been considered equivalent to the unit assigned to Poe member. Is of Early? and Middle Jurassic age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Poe Member
- Modifications:
-
- Revised
- AAPG geologic province:
-
- Williston basin
Summary:
Is reassigned from Poe (evaporite) Member of the Nesson Formation to the Poe Member of the Piper Formation in western ND. The Dunham Salt is reassigned as the Dunham Salt Bed(s) of the Poe Member. Jurassic in age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Poe Member
- Modifications:
-
- Revised
- AAPG geologic province:
-
- Williston basin
Summary:
Restricted to exclude Dunham Salt from the base in western ND, in Williston basin. Included in Piper Formation (revised). Overlain by Picard Member; underlain by Dunham Salt Member. Is Jurassic in age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Poe Evaporite Member*
- Modifications:
-
- Overview
- Age modified
- AAPG geologic province:
-
- Williston basin
Summary:
Is a member of Nesson Formation. Age changed from Early? and Middle Jurassic to Middle Jurassic (Bajocian). Is in central and eastern MT and western ND, in Williston basin. Summarizes lithology, basis for dating, distribution, and correlation.
Source: GNU records (USGS DDS-6; Denver GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).