Six to nine million years ago, the stretching and thinning of Earth's crust caused movement along the Teton Fault.  

The western block along the fault line forms the Teton Range, which forms the youngest mountain range of the Rocky Mountains

  The eastern block of the fault falls to form a valley called Jackson Hole.

The geological processes that led to the current formation of the oldest rocks in the Teton Range began about 2.5 billion years ago. 

During that time, sand and volcanic debris settled in an ancient ocean. 

 Additional sediment accumulated over millions of years and eventually heat and pressure transformed the sediment into gneiss.

Other intrusive igneous rocks are notable as black dikes of diabase, visible on the southwest side of Moran Mountain