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Geologic Unit: Dalles
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Map showing publication footprint
  • Usage in publication:
    • Dalles formation
  • Modifications:
    • Named
  • AAPG geologic province:
    • Columbia basin
Publication:

Cope, E.D., 1881, On certain Tertiary strata of the Great Basin: American Philosophical Society Proceedings, v. 19, p. 60-62.


Summary:

Unit is named the Dalles formation. Is a lacustrine unit found on the Columbia River, OR. Materials are sometimes coarse and gravelly. Underlain by lava flow that served as source of materials; overlain by beds of the second great volcanic outflow. Contains plant remains. (B896)

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


Map showing publication footprint
  • Usage in publication:
    • Dalles formation*
  • Modifications:
    • Adopted
    • Biostratigraphic dating
  • Dominant lithology:
    • Sandstone
    • Shale
    • Conglomerate
    • Tuff
    • Andesite
  • AAPG geologic province:
    • Blue Mountains province
    • Great Basin province
Publication:

Peck, D.L. (compiler), and Wells, F.G. (project director), 1961, Geologic map of Oregon west of the 121st Meridian: U.S. Geological Survey Miscellaneous Investigations Series Map, I-325, 1 sheet, scale 1:500,000, Prepared in cooperation with Oregon Dept. Geol. Min. Ind


Summary:

Dalles formation of Cope (1880) is adopted. Consists of thin- to medium-bedded semiconsolidated sandstone, sandy shale, conglomerate, tuff, and coarse mudflow breccia, all of andesitic and dacitic composition; to the west, includes intercalated andesite flows and in the Bend quadrangle includes a widespread dacite welded tuff. Age is Pliocene based on fossils [vertebrates, leaves, diatoms].

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


Map showing publication footprint
  • Usage in publication:
    • Dalles Formation*
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • Columbia basin

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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 ([ ]).