Looking at the oldest rocks of any region requires that we free
ourselves of the present-day geography. In the case of the
Colorado Plateau, the landscape that existed 1.7 billion years
ago was very far removed from the relatively stable arrangement
of horizontal sedimentary rocks and gently faulted and folded
monoclines and upwarps that exist today. It was not at the same
latitude and longitude, possibly not even in the same
hemisphere. The land we now know as the Plateau was connected to
a large landmass that today is Australia, Antarctica or Siberia.
How could everything be so completely different? Amazingly
enough, movements of 2-3 inches a year, added up over millions
and billions of years, are more than enough to account for the
huge changes we see in the rocks. Entire continents move
laterally, collide, split up, and reconfigure the world's
geography on a constant basis. The oldest rocks of the Colorado
Plateau are much changed from their time of origin. The original
sandstone, shale and volcanic rocks