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Geologic Unit: Bald Mountain
Map showing publication footprint
  • Usage in publication:
    • Bald Mountain Formation
  • Modifications:
    • Named
  • AAPG geologic province:
    • Cascades province
Publication:

Misch, Peter, 1966, Tectonic evolution of the Northern Cascades of Washington State, IN Symposium on the tectonic history and mineral deposits of the western Cordillera: Canadian Institute of Mining and Metallurgy Special Publication, v. 8, p. 101-148.


Summary:

Bald Mountain formation was assigned to Late Triassic and/or Early Jurassic (citing unpub. maps of Mount Baker and VanZandt quadrangles, ca. 1959) eugeosynclinal deposition in Church Mountain thrust plate south of border on western flank of northern Cascades [Whatcom County, Washington]. "Whether a Cultus [Formation of Canada] equivalent or not, this formation which is part of the Church Mountain thrust plate was deposited many miles east of the autochthonous Cultus strata."
[Type locality and origin of name not stated.]
[Name preempted by Bald Mountain Dacite of Cross (1896) in CO; Bald Mountain Gneiss of Smith and Packard (1919) in OR; Bald Mountain Lake Beds Member of Esmeralda Formation of Ferguson (1924) in NV; Bald Mountain Tonalite of Taubeneck (1957) in OR; Bald Mountain Basalt of Chesterman (1956) in CA; Bald Mountain olivine latite member (informal) of Lousetown Formation of Birkeland (1963) in CA.]

Source: Modified from GNU records (USGS DDS-6; Menlo GNULEX).


Map showing publication footprint
  • Usage in publication:
    • Bald Mountain member
  • Modifications:
    • Revised
  • Dominant lithology:
    • Conglomerate
  • AAPG geologic province:
    • Cascades province
Publication:

Johnson, S.Y., 1984, Stratigraphy, age, and paleogeography of the Eocene Chuckanut Formation, northwest Washington: Canadian Journal of Earth Sciences, v. 21, no. 1, p. 92-106.


Summary:

Rocks of Bald Mountain Formation of Misch (1966) southeast of Boulder Creek are here included in Bald Mountain Member (upper of 7) of Chuckanut Formation. It is proposed that sedimentary rocks northwest of Boulder Creek fault previously assigned to Bald Mountain Formation by Misch (1966) be considered undifferentiated part of Paleozoic-Mesozoic basement in area and that term "Bald Mountain Formation" be abandoned. Bald Mountain Member is named for Bald Mountain. Type section is on northeast side (NE/4 sec.12 T40N R6E, Whatcom Co,, WA). Composed of well indurated massive to crudely stratified clast-supported conglomerate. May be 550 m thick although uncertain because is highly fractured and faulted. On Bald Mountain unconformably overlies pre-Tertiary basement; in Boulder Creek overlies and possibly interfingers with Warnick member of Chuckanut Formation. Is probably late middle or early late Eocene age based on presence of angiosperm pollen (E. Leopold, personal commun., 1980) and palmetto fossils.

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 ([ ]).

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