- Usage in publication:
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- Rendezvous Metagabbro*
- Modifications:
-
- Named
- Geochronologic dating
- Dominant lithology:
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- Gabbro
- AAPG geologic province:
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- Northern Rocky Mountain region
Summary:
Named for outcrops between elev. 8,400 and 9,000 ft in small valley on east slopes of Rendezvous Mountain, Teton Co, WY in Northern Rocky Mountain region. Type locality is about 1.6 mi N 65 degrees W of lower terminus of aerial tramway, Teton village, Teton Village 7 1/2 min quad. Is a coarse-grained mafic rock that is nonlayered and very weakly foliated. Has a blotchy appearance due to irregular clots of dark-green hornblende 1 to several inches across set in matrix of light-gray plagioclase. Typically consists of 60-70 percent finely twinned plagioclase and 25-35 percent hornblende. A few small grains of quartz occur as poikilitic inclusions in hornblende and between larger plagioclase grains. North contact is a fault. To west passes beneath Paleozoic sedimentary rocks. To south has a sharp and concordant contact with migmatitic biotite gneiss. Rb/Sr data indicate a whole-rock isochron age of 2,875 +/-150 m.y.
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 ([ ]).