The Geology of
Virginia's Piedmont
 
    

Petersburg granite

The Petersburg Granite is composed of K-feldspar, quartz, plagioclase with minor amounts of biotite and muscovite. This igneous rock solidified deep in the crust during the late Paleozoic (~300 Ma).

 
    

Xenolith in the Petersburg granite

Inclusion of biotite-rich schist enclosed in Petersburg Granite. Biotite-rich schist represents a fragment of older rock that was caught up in the granitic magma when the Petersburg granite intruded. Exposure along James River on the south side of Belle Island, Richmond.

 
    
APPALACHIAN PLATEAU | VALLEY & RIDGE | BLUE RIDGE | PIEDMONT | COASTAL PLAIN
 

(3/8/99)
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