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Map showing publication footprint
  • Usage in publication:
    • Littlefield Rhyolite
  • Modifications:
    • Named
  • Dominant lithology:
    • Rhyolite
  • AAPG geologic province:
    • Snake River basin
Publication:

Kittleman, L.R., Green, A.R., Hagood, A.R., Johnson, A.M., McMurray, J.M., Russell, R.G., and Weeden, D.A., 1965, Cenozoic stratigraphy of the Owyhee region, southeastern Oregon: University of Oregon, Museum of Natural History Bulletin, no. 1, 45 p.


Summary:

Named for exposures at Littlefield ranch, sec.35 T23S R40E, Mahleur Co, OR. Consists of flaggy grayish-red or dark-gray multiple-flow porphyritic rhyolite with about 70% silica content. Conspicuously flow foliated. Thickness about 500 ft. In Crowley district overlies unnamed igneous complex. Probably unconformably underlies Butte Creek Volcanic Sandstone (new) which contains Barstovian mammalian fossils. Underlies Drip Spring Formation (new) in Harper Basin district. Overlies Hunter Creek Basalt (new) in Monument Peak, Malheur Gorge, and Harper Basin districts. Has been dissected and faulted, probably in late Miocene time and forms basin of deposition for later rocks. Is considered Miocene age.

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


Map showing publication footprint
  • Usage in publication:
    • Littlefield Rhyolite
  • Modifications:
    • Mapped
  • AAPG geologic province:
    • Snake River basin
Publication:

Kittleman, L.R., Green, A.R., Haddock, G.H., Hagood, A.R., Johnson, A.M., McMurray, J.M., Russell, R.G., and Weeden, D.A., 1967, Geologic map of the Owyhee region, Malheur County, Oregon: University of Oregon, Museum of Natural History Bulletin, no. 8, 1 sheet, (incl. geologic map, scale 1:125,000)


Summary:

Shown on geologic map of Owyhee district, Malheur Co, OR. Described as multiple flows of grayish-red porphyritic, flow-foliated rhyolite with phenocrysts of plagioclase, potassium feldspar, and pyroxene. Overlies Dinner Creek Welded Ash-Flow Tuff and Hunter Creek Basalt. Underlies Drip Spring Formation and unconformably underlies Quaternary alluvium. Age is shown as Miocene.

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


Map showing publication footprint
  • Usage in publication:
    • Littlefield Rhyolite
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • Snake River basin
Publication:

Kittleman, L.R., 1973, Guide to the geology of the Owyhee region of Oregon: University of Oregon, Museum of Natural History Bulletin, no. 21, 61 p.


Summary:

Age for Littlefield Rhyolite is given as late Miocene [no basis given]. On the west in Cottonwood basin, unit underlies Tims Peak Basalt (of early Pliocene age); on the east in Cottonwood basin underlies both Grassy Mountain Formation and Tims Peak Basalt. In center of basin Littlefield Rhyolite sank down forming depression which received Drip Spring Formation and Bully Creek Formation.

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


Map showing publication footprint
  • Usage in publication:
    • Littlefield Rhyolite
  • Modifications:
    • Geochronologic dating
  • AAPG geologic province:
    • Snake River basin
Publication:

Laursen, J.M., and Hammond, P.E., 1974, Summary of radiometric ages of Oregon and Washington rocks through June, 1972: Isochron/West, no. 9, 32 p.


Summary:

Littlefield Rhyolite. Sample from Millers Cow Camp near Littlefield Ranch, in SW/4 sec. 35, T. 23 S., R. 40 E., Malheur County, Oregon. K-Ar age on plagioclase 17.5 +/-0.6 Ma.

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


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For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

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