- Usage in publication:
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- Sugarloaf metaquartzite
- Modifications:
-
- Named
- Dominant lithology:
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- Metaquartzite
- AAPG geologic province:
-
- Northern Rocky Mountain region
Summary:
No type locality designated. Is exposed on the northeast side of Sugarloaf Peak, on the inlet to Brooklyn Lake in Albany Co, WY, T16N, R79W, in the Northern Rocky Mountain region. Is a dense, fine-grained vitreous metaquartzite of extreme purity and dull-white color. Near the top well-worn quartz pebbles are present. Some of the bedding planes are ripple marked. Distinguishable from the other metaquartzites by its purity. Exposed thickness is 1,900 ft. Lower contact with Lookout schist (new) is gradational. Relation to the younger Nash marble series (new) is unknown. Assigned to the pre-Cambrian. Is probably early Algonkian or Proterozoic.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Sugarloaf Quartzite
- Modifications:
-
- Revised
- Overview
- AAPG geologic province:
-
- Northern Rocky Mountain region
Summary:
Revised as a formation, the upper formation (of 6) assigned to the lower part of the Libby Creek Group of the Snowy Pass Supergroup (first used) in south-central WY in the Northern Rocky Mountain region. Overlies Lookout Schist of the lower part of the Libby Creek. Is in fault contact with the overlying Nash Fork Formation, basal formation of the upper part of the Libby Creek. Consists of monotonous white, medium-grained quartz arenite about 580 m thick. Is medium to thin bedded. Has planar and trough crossbeds, and symmetric, interference, and climbing ripples. Sediment transport was dominantly west-southwest. Oscillation ripple marks suggest shallow marine environment. Geologic map; stratigraphic chart. Of Proterozoic age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Sugarloaf Quartzite*
- Modifications:
-
- Revised
- AAPG geologic province:
-
- Northern Rocky Mountain region
Summary:
Assigned as the upper formation of six of the lower part of the Libby Creek Group of the newly defined Snowy Pass Supergroup in the Medicine Bow Mountains, WY in the Northern Rocky Mountain region. Separated from the older Lookout Schist of the lower part of the Libby Creek and from the younger Nash Fork Formation of the upper part of the Libby Creek by faults. Correlated with upper part of the Copperton Formation (formerly Copperton Quartzite) of the middle part of the Snowy Pass Group of the Sierra Madre. Geologic map; correlation chart. Of Early Proterozoic age.
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 ([ ]).