- Usage in publication:
-
- Cottonwood Bay Greenstone*
- Modifications:
-
- Named
- Dominant lithology:
-
- Hornfels
- Greenstone
- AAPG geologic province:
-
- Alaska Peninsula province
- Alaska Southwestern region
Summary:
Named for exposures at its type locality on south shore near head of Cottonwood Bay, Cook Inlet, Iliamna quad, Alaska Peninsula, AK. Composed of dark-green, gray mafic volcanic rocks altered to hornfels and chloritic greenschist. Original porphyritic texture mostly altered to hornfelsic and granoblastic. Is over 600 m thick. Locally so intensely altered as to be part of Kakhonak Complex (new); locality cannot be distinguished from Talkeetna Formation; underlies Bruin Limestone Member (new) (Kamishak Formation). Is presumably of Late Triassic (probably no older than Norian) 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 ([ ]).