- Usage in publication:
-
- Tlevak Basalt*
- Modifications:
-
- Named
- Dominant lithology:
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- Basalt
- AAPG geologic province:
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- Alaska Southeastern region
Summary:
Named for Tlevak Strait. Best exposed along shoreline off west coast of Prince of Wales Island in vicinity of Tlevak Strait, Craig B-4 quad, southeastern AK. May also be exposed along northeast shore of Trocadero Bay, Prince of Wales Island about 9 mi to the northeast. Consists of strongly jointed olivine basalt with subhorizontal slabs and locally vertical columnar joints. Is remarkably fresh and contains phenocrysts of olivine and plagioclase. Total thickness is uncertain; is probably less than 100 ft thick. Locally unconformably overlies Ladronus Limestone; elsewhere apparently overlies Port Refugio and Peratrovich Formations; appears to rest unconformably on rocks of Late Devonian, Mississippian, and Pennsylvanian ages. Tentatively assigned Tertiary or Quaternary age on basis of its stratigraphic position and its freshness and lack of deformation.
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 ([ ]).