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NGMDB
Geologic Unit: Pogonip
Map showing publication footprint
  • Usage in publication:
    • Pogonip Group*
  • Modifications:
    • Areal extent
  • Dominant lithology:
    • Limestone
    • Shale
    • Quartzite
    • Dolomite
  • AAPG geologic province:
    • Great Basin province
Publication: Summary:

Is Lower and Middle Ordovician formation shown only in cross sections in southern part of Mountain Home Range in western Millard and Beaver Cos, southwest UT (Great Basin province). Is oldest bedrock unit indicated in map area. Is shown below Eureka Quartzite (Middle Ordovician), which is the oldest bedrock unit mapped in study area. Pogonip is described as bioclastic limestone interbedded with olive-gray shale and, in the upper 100 m, with a few beds of reddish-brown quartzite and brownish-gray coralline dolomite. Subsurface only on this map. The Pogonip is more than 1000 m thick in adjacent quadrangles [Tunnel Spring quad., USGS MF-1334, (Hintze, 1981); Halfway Summit quad., USGS MF-1153, (Best and Hintze, 1980)].

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

NGMDB
Map showing publication footprint
  • Usage in publication:
    • Pogonip Group*
  • Modifications:
    • Areal extent
    • Overview
  • AAPG geologic province:
    • Great Basin province
Publication: Summary:

Lower and upper parts mapped separately in southwest part of quad, Lincoln Co, NV, Great Basin province. Formations of Pogonip that occur over most of west-central UT and central NV cannot be identified in southeastern NV because of facies changes. Quad contains easternmost exposures of Ordovician rocks in southern UT and NV; rocks were tectonically transported eastward as part of Tule Springs allochthon. Lower part consists of light bluish- or yellowish-gray silty dolomite with some small chert nodules; includes few thin beds of orange-weathering algal boundstone; thickness is 135 m; conodonts represent lower part of North American conodont fauna D of middle Ibexian (middle Early Ordovician) age based on presence of PROTOPANDERODUS LEEI and "old" aspect of "SCOLOPODUS" GRACILIS elements. Upper part consists of thin- to medium-bedded dolomitic limestone, silty limestone, and few intraformational conglomerate beds; generally nonresistant and forms yellowish slopes; 150 m thick where least deformed. Upper part divided into four subunits (not mapped separately); within lowermost subunit 1 conodonts represent middle part of conodont fauna D (middle Ibexian); within uppermost subunit 4 conodonts represent HISTIODELLA HOLODENTATA Zone of [early] Middle Ordovician (middle Whiterockian) age. Conformably overlies Nopah Dolomite (redescribed); conformably underlies Eureka Quartzite. Middle Early Ordovician to early Middle Ordovician age.

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

NGMDB

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 ([ ]).

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