Usage:
Usibelli Group (AK*)
Subunits:
(alphabetical) --all in AK*: Grubstake Formation, Healy Creek Formation, Lignite Creek Formation, Sanctuary Formation, Suntrana Formation.
Geologic age:
Tertiary
Eocene, late*
Miocene, early*
Miocene, middle*
Miocene, late*
Type section, locality, area and/or origin of name:
A composite of type sections of Healy Creek, Sanctuary, Suntrana, and Lignite Creek Formations, and reference section of Grubstake Formation, on north bank of Healy Creek and above lower part of Suntrana Creek, Healy D-4 quadrangle (scale 1:63,360), AK (Wahrhaftig, 1987).
AAPG geologic province:
Alaska East-Central region*
Alaska Southern region*
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 ([ ]).