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National Geologic Map Database

Geologic Unit: Unalaska

Usage:

Unalaska Formation (AK*)


Subunits:

Dutch Harbor Member (AK*).


Geologic age:

Tertiary
Miocene, early*
and older


Type section, locality, area and/or origin of name:

Named from exposures on Unalaska Island, Aleutian Islands, AK. Exposed over two-thirds of the island (Drewes and others, 1961).


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 ([ ]).