Usage:
No current usage.
(†Idak Basalt (AK) replaced with Ashishik Basalt (locally) and unnamed units. See Ashishik.)
Geologic age:
Tertiary
Quaternary
Type section, locality, area and/or origin of name:
Not designated. Occurs on Mount Idak and ridges to northeast. Origin of name not stated by author, but probably named from Mount Idak in southwest part of Unalaska quadrangle (scale 1:250,000) (Byers and others, 1947).
AAPG geologic province:
Aleutian Islands province
Alaska Southwestern 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 ([ ]).