- Usage in publication:
-
- Pecos Complex
- Modifications:
-
- Named
- Geochronologic dating
- Dominant lithology:
-
- Volcanics
- Iron-formation
- Sandstone
- Shale
- Graywacke
- AAPG geologic province:
-
- Southern Rocky Mountain region
Summary:
Name applied to rocks formerly known informally as the "Pecos greenstone belt." Occupies an area of about 650 sq km in headwaters of Pecos River, northeast of Santa Fe, Santa Fe Range, Mora and San Miguel Counties, New Mexico [Southern Rocky Mountain region]. Four rock types recognized: (1) metavolcanic rocks with minor interbedded volcaniclastic rocks and iron-formation; (2) metasedimentary rocks including feldspathic sandstone, shale, volcaniclastic graywacke, carbonate, and iron-formation; (3) intrusive felsic and mafic rocks of a subvolcanic complex; (4) younger granitic rocks. Age is Early Proterozoic (1,720 Ma, based on U-Pb zircon dating of the metavolcanic and subvolcanic intrusive rocks). Is younger than the Gold Hill Complex (new) and the Moppin Complex (revised), and older than the Vadito Group (revised). Report includes geologic map, nomenclature chart.
Type locality not designated.
Source: Modified from 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 ([ ]).