Tuesday, September 16, 2014

Faults Created The Teton Range


Grand Teton National Park was established February 26, 1926. It is weird to think that the mountains in the park were not always there; in fact the mountains were created starting about 10 million years ago due to massive earthquakes along the Teton fault, which were extension faults.  The massive earthquakes, which were measured up to magnitude 7.5, shifted the mountains upward and the valley downward.  


Great example of the Tetons and the valley.
The left mountain is Mt. St. John and the right is Rockchuck Peak.




Faults happen along the fault line, creating the foot wall and the hanging wall to separate along the fault plane.  The footwall (mountains) rises, and the hanging wall (valley) drops creating space in-between the foot wall and the hanging wall called the fault scarp. 


Diagram to show extension faulting.


The Teton fault us about 40 miles long along the base of the range.  The tallest mountain in the range is 13,770 which is an astonishing 7,000 feet above the valley.  The total distance between the foot wall and hanging wall is up to 30,000 feet.  Jackson Hole dropped around 20,000 feet while the mountains rose.  

In my opinion, Grand Teton National Park is one of the best examples of faulting in the United States!  It is so incredible that faulting creates an entire mountain range. 
Arial view of the Teton Mountain range.


 
 References