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Map showing publication footprint
  • Usage in publication:
    • Mallard Lake Member*
  • Modifications:
    • Named
  • Dominant lithology:
    • Rhyolite
  • AAPG geologic province:
    • Yellowstone province
Publication:

Christiansen, R.L., and Blank, H.R., Jr., 1972, Volcanic stratigraphy of the Quaternary rhyolite plateau in Yellowstone National Park, IN Geology of Yellowstone National Park: U.S. Geological Survey Professional Paper, 729-B, p. B1-B18. [Available online from the USGS PubsWarehouse: http://pubs.er.usgs.gov/pubs/pp/pp729B]


Summary:

Named as a member of Plateau Rhyolite (new) for exposures around Mallard Lake (its type area), about 5 km northeast of Old Faithful, southwest Yellowstone National Park, WY in Yellowstone province. Base of member not exposed. Is broken by northwest-trending normal faults that form a complex graben along axis of dome. Is overlain by Upper Basin and Central Plateau Members (new) of Plateau Rhyolite. No complete sections exposed. Most exposures are crystallized rhyolite with 20-30 percent phenocrysts of quartz and sanidine. Flow layering is well displayed. Is commonly thinly flow laminated. Is younger than the 600,000 year Lava Creek Tuff--perhaps only slightly. Is overlain by a 530,000 year-old flow. Is part of the third volcanic cycle of the Yellowstone Plateau.

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


Map showing publication footprint
  • Usage in publication:
    • Mallard Lake Member*
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • Yellowstone province
Publication:

Christiansen, R.L., 1974, Geologic map of the West Thumb quadrangle, Yellowstone National Park, Wyoming: U.S. Geological Survey Geologic Quadrangle Map, GQ-1191, scale 1:62,500


Summary:

Mallard Lake Member of Plateau Rhyolite. Age and stratigraphic position changed from oldest and lowermost member of Plateau. As changed, overlies Upper Basin Member of Plateau; underlies Central Plateau Member of Plateau. Age is Pleistocene. Study area in Yellowstone National Park, Wyoming.
See also R.L. Christiansen and H.R. Blank, Jr., 1974, Geol. map Old Faithful quad., Yellowstone Natl. Park, WY, USGS Geol. Quad. Map GQ-1189; R.L. Christiansen and H.R. Blank, Jr., 1974, Geol. map Madison Junction quad., Yellowstone Natl. Park, WY, USGS Geol. Quad. Map GQ-1190.

Source: Changes in stratigraphic nomenclature, 1975 (USGS Bull. 1422-A, p. A24-A25).


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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