Types
Algoma-type , Lake Superior-type and Superior-type
Welded tuff, Rhyolitic tuff, Basaltic tuff, Trachyte tuff, Andesitic tuff and Ignimbrite.
Features
Is one of the oldest rock
Always found as volcanic pipes over deep continental crust
Archaeological Significance
Monuments
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Famous Monuments
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Easter Island in the Polynesian Triangle, Pacific Ocean
Sculpture
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Famous Sculptures
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Pictographs
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Petroglyphs
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Figurines
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Fossils
Present
Absent