Brief outline of Pennsylvania’s Geologic History

Kurt Friehauf

245-210 million years ago – Pangea

Pangea, the supercontinent that made up essentially all of the landmasses during its time, lasted tens of millions of years.  The collision-zone mountains (i.e., the Appalachians and associated ranges) began to wear down.  Although the mountains that preceded the Appalachians were historically at the edge of the continent, the Appalachian Mountains themselves were geographically near the center of the great Pangea landmass.  Rain and wind and snow slowly nibbled away at them, though, breaking the mountains down into sand and soil that washed down onto the lowlands.



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