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Map showing publication footprint
  • Usage in publication:
    • Esperanza trachyte*
  • Modifications:
    • Named
  • Dominant lithology:
    • Trachyte
  • AAPG geologic province:
    • Plateau sedimentary province
Publication:

Ransome, F.L., 1923, Geology of the Oatman gold district, Arizona; a preliminary report: U.S. Geological Survey Bulletin, 743, 58 p.


Summary:

Named for Esperanza Canyon, secs 33 and 34, T19N, R20W, Mohave Co, AZ, Plateau sedimentary province. No type locality designated. Overlies a 100-150 ft shale unit, a weathering product at top to Alcyone trachyte (new). Is restricted to the southern part of the district. Geologic map. Is reddish-brown (weathered), purple-gray (fresh), compact, cliff-making, splintery fracture, hard-ringing or phonolitic latitic trachyte. Weathers into talus slab 1/2 to 3/4 inches thick and 18 inches across, and into slender splinters 3/4 inch thick, 2 inches wide, 2 ft long. Composed mainly of very fine textured felt of tiny feldspar crystals under the microscope. Chemically like the Alcyone. Is mostly one flow, possibly two flows. Some associated breccia. Estimated to be about 1,000 ft thick. Extends beyond map area. Thins rapidly northward. Absent north of Sunnyside Wash. Was covered by Oatman andesite. Tertiary age.

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


Map showing publication footprint
  • Usage in publication:
    • Esperanza Quartz Latite*
  • Modifications:
    • Redescribed
    • Age modified
  • Dominant lithology:
    • Quartz latite
  • AAPG geologic province:
    • Plateau sedimentary province
Publication:

DeWitt, Ed, Thorson, J.P., and Smith, R.C., 1991, Geology and gold deposits of the Oatman district, northwestern Arizona, IN DeWitt, Ed, and others, Epithermal gold deposits, Part II: U.S. Geological Survey Bulletin, 1857-I, p. 1-28.


Summary:

Esperanza Trachyte redescribed as Esperanza Quartz Latite because it is a lava flow (or flows) of alkalic quartz latite. Has an average of 10 percent phenocrysts, predominantly plagioclase and biotite. Is found only to south of Oatman, Mohave Co, AZ in the Plateau sedimentary province. Geologic maps. Ranges between 60 to 300 m thick. Overlies Alcyone Formation (redescribed) and underlies Oatman Andesite. Erupted between 19 and about 23 Ma. Age modified from Tertiary to Miocene. Chemical analyses.

Source: GNU records (USGS DDS-6; Denver 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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