- Usage in publication:
-
- Kaltag formation*
- Modifications:
-
- Named
- Biostratigraphic dating
- Dominant lithology:
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- Sandstone
- Shale
- Coal
- AAPG geologic province:
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- Alaska West-Central region
Martin, G.C., 1926, Mesozoic stratigraphy of Alaska: U.S. Geological Survey Bulletin, 776, 493 p.
Summary:
Named for exposures on northwest bank of Yukon River between Kaltag and Williams mine, lower Yukon and Norton Bay districts, west-central AK. Consists of fresh-water sandstone, shale, and coal beds with possibly some thin marine members. Contains fossil plants, fresh-water invertebrates, and perhaps a few marine invertebrates. Is over 800 ft thick. Conformably overlies Nulato formation. Locally unconformably underlies unconsolidated Quaternary deposits. Age is Late Cretaceous based on fossils. [Extensive list of fossils from unit identified by several paleontologists included in report.]
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Kaltag formation*
- Modifications:
-
- Revised
- Age modified
- Biostratigraphic dating
- AAPG geologic province:
-
- Alaska West-Central region
Summary:
Correlation chart shows Kaltag formation in Shaktolik group in Nulato-Norton Bay and lower Yukon area. Age shown as Early Cretaceous (Albian) based on [reexamination] of fossils from unit.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Kaltag Formation*
- Modifications:
-
- Revised
- Age modified
- Biostratigraphic dating
- AAPG geologic province:
-
- Alaska West-Central region
Summary:
[Kaltag Formation is removed from Shaktolik Group due to abandonment of name Shaktolik.] Unit not mapped beyond "type" area due to wide variations in lithology and poor exposures. Age is Early and Late Cretaceous due to recent discovery of Cenomanian mollusk TURRILITES ACUTUS Passy from underlying marine beds on Anvik River, thus providing firm evidence that at least some of plant-bearing beds included in Kaltag are Late Cretaceous in age.
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 ([ ]).