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 Main Menu > GeoGallery > Rocks > Gneiss > Gneiss 
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Gneiss This 1.7 billion-year-old gneiss is part of a 500-km (300-mi) wide area that accreted to North America’s southern margin. Once sedimentary, the rock was metamorphosed and folded. It contains layers and veins of granite.
Group: Metamorphic |
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