U.S. Geological Survey Home AASG Logo USGS HOME CONTACT USGS SEARCH USGS
National Geologic Map Database
Map showing publication footprint
  • Usage in publication:
    • Tangle Lakes Formation
  • Modifications:
    • Named
  • Dominant lithology:
    • Tuff
    • Andesite
    • Basalt
  • AAPG geologic province:
    • Alaska Southern region
Publication:

Stout, J.H., 1976, Geology of the Eureka Creek area, east-central Alaska Range: Alaska Division of Geological and Geophysical Surveys Geologic Report, no. 46, 32 p.


Summary:

Named for Tangle Lakes. Type locality designated as exposures on south limb of Amphitheater syncline near Tangle Lakes and upper Delta River, Eureka Creek area, Mount Hayes A-4 and A-5 quads, east-central Alaska Range, AK. Is middle unit of three of Amphitheater Group. Composed of green to gray siliceous tuff, agglomerate interlayered with tuffaceous sedimentary rocks and black shale, and pillowed andesite and basalt. Is 3,500 m thick. Overlies Paxson Mountain Basalt (new) and underlies Boulder Creek Volcanics (new) (both of Amphitheater Group). Is Late Triassic 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 ([ ]).

Accessibility FOIA Privacy Policies and Notices

USA Gov U.S. Department of the Interior | U.S. Geological Survey
Supported by the National Cooperative Geologic Mapping Program
Page Contact Information: Personnel
Page Last Modified: Thu 28 Aug 2025 02:47:06 PM MDT