- Usage in publication:
-
- Swakane gneiss
- Modifications:
-
- Named
- Dominant lithology:
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- Gneiss
- Amphibolite
- Schist
- Marble
- AAPG geologic province:
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- Cascades province
Summary:
Named for Swakane Creek, Entiat Mountains, Chelan quad, Cascade Range, central WA, area of finest occurrence. Consists of complex of remarkably foliated, highly metamorphic rocks, in part sedimentary and in part igneous. Biotite gneiss predominates; also includes granodiorite gneiss, amphibolite, amphibolite schist, marble, mica schist, and serpentine. Unconformably underlies Swauk formation of early Eocene age; intruded by Chelan batholith (probably Late Jurassic age). On basis of comparative metamorphism [with Peshastin formation] age of unit is pre-Ordovician.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Swakane Biotite Gneiss*
- Modifications:
-
- Age modified
- AAPG geologic province:
-
- Cascades province
Summary:
Metamorphic age of Swakane Biotite Gneiss given as Late Cretaceous. Protolithic age shown as Precambrian.
Source: GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Swakane Biotite Gneiss*
- Modifications:
-
- Areal extent
- AAPG geologic province:
-
- Cascades province
Summary:
Unit is geographically restricted from Lucerne 15' quad [see Cater and Wright (1967 -GQ-647)]. Its rocks in Lucerne 15' quad are reassigned to Skagit Gneiss Complex.
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 ([ ]).