Blue Ridge province - The Geology of Virginia
 
    

F A U L T   Z O N E   L I T H O L O G Y

Mylonite

Photomicrograph of mylonite from the Blue Ridge province. Mylonites are rocks that form in ductile fault zones deep within the crust. Quartz ribbon (q) was originally an equant grain in a granite, but has been stretched (in a taffy-like manner) into an elongate grain. The fine-grained matrix (m) is composed of minerals that recrystallized during deformation. Field of View 4 x 2.7 mm, Cross Polarized Light.

 
    

Breccia of the Antietam 
Formation

Photomicrograph of fault breccia in the Antietam Formation, Blue Ridge province. Breccias form when rocks are extensively fractured in fault zones and are cemented together when minerals precipitate in the cracks and fractures. Note the angular fragments (fr) of quartz sandstone in a matrix of fine-grained iron oxide cement (ic). Field of View 4 x 2.7 mm, Cross Polarized Light.

 
    

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

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