- Usage in publication:
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- Sheep Pasture Formation
- Modifications:
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- Areal extent
- Geochronologic dating
- AAPG geologic province:
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- Permian basin
Summary:
Sheep Pasture Formation mapped in the Davis Mountains area, Jeff Davis Co, west TX in Permian basin. Consists of slightly porphyritic rhyolite, indurated to friable, grayish purple to brown; fine-grained vitric tuff locally near top. Thickness at type section 510 ft. K-Ar age of 36.2 +/-0.4 m.y. obtained (2 samples). [Unclear on Correlation of Map Units if Sheep Pasture is part of Vieja Group.] Shown as above Frazier Canyon Formation (first used) and below Merrill Formation. [Author states that correlation of volcanic rocks from area to area on Marfa sheet is uncertain--little attempt is made to correlate between areas. The rocks are described by area.] Of Oligocene age. Geologic map.
Source: GNU records (USGS DDS-6; Denver GNULEX).
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
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