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Map showing publication footprint
  • Usage in publication:
    • Outlet Tunnel quartz latite*
  • Modifications:
    • Original reference
  • Dominant lithology:
    • Quartz latite
  • AAPG geologic province:
    • San Juan Mountains province
Publication:

Emmons, W.H., and Larsen, E.S., 1923, Geology and ore deposits of the Creede district, Colorado: U.S. Geological Survey Bulletin, 718, 198 p., (incl. geologic map, scale 1:24,000) [http://ngmdb.usgs.gov/Prodesc/proddesc_25596.htm]


Summary:

Outlet Tunnel quartz latite of Alboroto group of Potosi volcanic series. Is a chaotic aggregate of lava flows and breccia beds. Found in only two small bodies in canyon of East Willow Creek a short distance north of Ridge Mine [in SW/4 sec. 18] and has not been recognized in reconnaisance of adjoining region. Is basal formation of Alboroto group of Potosi volcanic series. Unconformably underlies at least a part of Willow Creek rhyolite. Thickness 250 to 350+ feet. Age is Miocene.
Named from development at Outlet Tunnel [now Outlet Mine], Creede district, southwestern CO. [Outlet Mine in center of N/2 sec. 18, T. 42 N., R. 1 E., San Luis Peak 7.5-min quadrangle, Mineral Co., Creede district, southwestern CO (USGS Historical Topographic Map Collection, accessed February 28, 2013).]

Source: US geologic names lexicon (USGS Bull. 896, p. 1578).


Map showing publication footprint
  • Usage in publication:
    • Outlet Tunnel Member*
  • Modifications:
    • Revised
  • AAPG geologic province:
    • San Juan Mountains province
Publication:

Steven, T.A., and Ratte, J.C., 1964, Revised Tertiary volcanic sequence in the central San Juan Mountains, Colorado; Article 132, IN Geological Survey Research 1963; short papers in geology and hydrology; Articles 122-170: U.S. Geological Survey Professional Paper, 475-D, p. D54-D63. [Available online from the USGS PubsWarehouse: http://pubs.er.usgs.gov/pubs/pp/pp475D]


Summary:

Reduced in stratigraphic rank (Outlet Tunnel Quartz Latite of Emmons and Larsen, 1923) to Outlet Tunnel Member, older member of the La Garita Quartz Latite (in this paper). Assigned to the middle and late Tertiary. Formed before the Phoenix Park Member and prior to subsidence of the La Garita cauldron in the San Juan Mountain province.

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


Map showing publication footprint
  • Usage in publication:
    • Outlet Tunnel Member†
  • Modifications:
    • Abandoned
  • AAPG geologic province:
    • San Juan Mountains province
Publication:

Steven, T.A., Lipman, P.W., and Olson, J.C., 1974, Ash-flow stratigraphy and caldera structures in the San Juan volcanic field, southwestern Colorado, IN Cohee, G.V., and Wright, W.B., Changes in stratigraphic nomenclature by the U.S. Geological Survey, 1972: U.S. Geological Survey Bulletin, 1394-A, p. A75-A82.


Summary:

Pg. A34-A35, A78. Outlet Tunnel Member† of La Garita Tuff. Steven and Ratte's (1964) Outlet Tunnel Member is same as large mass of intracaldera rocks of the La Garita Member (revised) of Fish Canyon Tuff (revised) and is herein abandoned.

Source: Publication.


Map showing publication footprint
  • Usage in publication:
    • Outlet Tunnel Member*
  • Modifications:
    • Age modified
  • AAPG geologic province:
    • San Juan Mountains province
Publication:

Map showing publication footprint
  • Usage in publication:
    • Outlet Tunnel unit*
  • Modifications:
    • Reinstated
  • AAPG geologic province:
    • San Juan Mountains province
Publication:

Lipman, P.W., Sawyer, D.A., and Hon, K., 1989, Central San Juan caldera cluster; Road log 3, South Fork to Lake City, IN Chapin, C.E., and Zidek, Jiri, eds., Field excursions to volcanic terranes in the western United States; Volume 1, Southern Rocky Mountain region: New Mexico Bureau of Mines and Mineral Resources Memoir, no. 46, p. 330-349., Produced for the International Association of Vocanology and Chemistry of the Earth's Interior (IAVCEI) General Assembly held in Santa Fe, New Mexico, June 25 - July 1, 1989


Summary:

Reinstated as an informal unit within Carpenter Ridge Tuff. Study is in Creede area, Mineral Co, CO, San Juan Mountain province. Unit now interpreted as landslide and talus breccia, composed of Fish Canyon Tuff, derived during subsidence of Bachelor caldera (in La Garita Mountains). Bachelor caldera was source of Carpenter Ridge. Previous workers have interpreted unit to be part of main mass of intracaldera Fish Canyon in resurgent dome of La Garita caldera and was thought to be part of floor of Bachelor caldera. All previously mapped Fish Canyon for 4 km up East Willow Creek from Outlet Tunnel mine is landslide and talus debris within Bachelor caldera, rather than in-place fill of La Garita caldera. Unit had similar origin as Phoenix Park unit (revised to informal status), though Outlet Tunnel occurs lower in caldera fill. Oligocene age.

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


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

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).