- Usage in publication:
-
- Bergman series*
- Modifications:
-
- Adopted
- Dominant lithology:
-
- Sandstone
- Shale
- Conglomerate
- AAPG geologic province:
-
- Alaska West-Central region
Summary:
[Named by Schrader (1902) for group of rocks overlying Koyukuk series]. [Type area designated] along Koyukuk River between Arctic City and Bergman, Koyukuk basin, west-central AK. Consists of folded sandstones, fine conglomerates, and dark sandy shales, the sandstones and shales, usually alternating in thin bands, but also contains broad belts of shale many 100's of ft thick. To the north sandstones are replaced by conglomerate which forms base of series. Contains no determinable fossils. Age is probably Mesozoic based on stratigraphic relations. [Note that Schrader (1902) assigned series to Cretaceous.]
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Bergman Groupâ€
- Modifications:
-
- Abandoned
- AAPG geologic province:
-
- Alaska West-Central region
Summary:
Names for Early and Late Cretaceous beds (in Yukon-Koyukuk province) referred to as Bergman Group and Shaktolik Group by earlier workers, are considered to have little practical value due to vague definition of lithology and areal limits. Rocks are subdivided into four unnamed lithologic units in this report.
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 ([ ]).