The National Geologic Map Database is migrating to a new infrastructure. We apologize for any service disruptions during this process.
|
|---|
- Usage in publication:
-
- Cheeneetnuk Limestone
- Modifications:
-
- Named
- Biostratigraphic dating
- AAPG geologic province:
-
- Alaska west-central region
Summary:
Unit is named the Cheeneetnuk Limestone. Is equivalent to unit mDlc of Gilbert (1981) and forms the uppermost horizon within an Ordovician to Middle Devonian carbonate-platform sequence exposed on the north side of the Farewell fault in the McGrath A-4 and A-5 quads, AK. Consists of dark-gray well-bedded, argillaceous, micritic limestone. Conformably overlies unnamed dolomite of unit lDd; conformably underlies unnamed argillite and chert of unit uPzac, both of Gilbert (1981). Thickness is 457 m at the type section. Age is Middle Devonian (Eifelian) in the upper part of the section based on fossils. Lack of fossils in lower part of unit makes age assignment questionable; relative thickness of section suggests that the base of the formation is in the Early Devonian. (B1565)
Source: GNU records (USGS DDS-6; Menlo 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 ([ ]).