Paleogeography and Geologic History

The chart below shows all colors and symbols used on the tectonic maps.

  • Chart showing all colors and symbols used on tectonic maps

    The two map below compare Jurassic and Present terrane distribution
  • Map showing present distribution of terranes
  • Map showing general Jurassic distribution of terranes (modified from Saleeby and Busby-Spera, 1992)

    The following paleogeographic and tectonic maps and accompaning text summarize our understanding of the Mesozoic geologic history of Western North America.

  • Permian (290Ma)
  • Triassic(240Ma)
  • Early Jurassic (180Ma)
  • Middle Jurassic (160Ma)
  • Late Jurassic (145Ma)
  • Early Cretaceous (125Ma)
  • Late Early Cretaceous (105Ma)
  • Late Cretaceous (85Ma)
  • Tertiary - Cretaceous (65Ma)
  • Eocene (50Ma)

    Return to WUS Paleogeography