Plate Tectonics Topics

Plate Tectonics History of Virginia (Part 3)

560 Million Years Ago


• The rifting continental fragments separated completely, and basalt poured out to form new seafloor crust.

560 Map
Reconstruction of the world 560 million years ago. Note the development of an ocean that was not previously present forming along what is now the east coast of North America. This ocean is called Iapetus. (Image courtesy of the United States Geological Survey)

• A new ocean basin called Iapetus formed. 

• The basalt that made up parts of the seafloor of Iapetus can now be found in the Catoctin rocks in the Blue Ridge of central and northern Virginia.

Catoctin FormationAncient basaltic lavas in the Catoctin Formation showing oval-shaped "pillow" structure indicating eruption underwater. (Photograph by Nick Evans)

MapThe above photograph shows pillow lavas in the Catoctin Formation in Albemarle County.  The pillows were formed when molten lava erupted into seawater as continents rifted apart to form the ancient ocean Iapetus.