- Usage in publication:
-
- Green Ranch Quartzite Member
- Modifications:
-
- Named
- Dominant lithology:
-
- Quartzite
- AAPG geologic province:
-
- Southern Rocky Mountain region
Summary:
Named as a member of Junction Formation for exposures on prominent ridge south of Green Ranch in northeast corner sec 29, T3S, R70W, Ralston Buttes quad, Jefferson Co, CO in the Southern Rocky Mountain region. These exposures designated the type area. Occurs in west part of area. Not shown on geologic maps or on cross section. Composed of fine- to medium-grained, thin-bedded quartzite, 8 to 10 ft thick that occurs in middle or top of unit depending on position above or below unconformity. Precambrian age.
Source: GNU records (USGS DDS-6; Denver GNULEX).
- Usage in publication:
-
- Green Ranch Quartzite
- Modifications:
-
- Overview
- AAPG geologic province:
-
- Southern Rocky Mountain region
Summary:
As a member of Junction Formation is one of several units defined in a narrow belt along east-central Front Range, near Golden, Jefferson Co, CO in Southern Rocky Mountain region. Of doubtful use elsewhere. Assumed direction of stratigraphic sequence is debatable. Belongs with pre-1,700 m.y. metamorphic complex, or of Precambrian X 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 ([ ]).