Few mountain ranges in the world rise up from adjacent valleys as dramatically as the Teton Range of northwestern Wyoming, USA.  Seven of the mountains here top out at >12,000' elevation.  The entire range was uplifted approximately 30,000 feet during the late Cenozoic by normal faulting along the Teton Fault.  Much of that offset has been eroded away.  The adjacent valley, Jackson Hole, was downdropped during the same faulting events.  The rocks making up the faces of the Tetons are Precambrian basement rocks - principally Neoarchean metamorphics & intrusive igneous rocks (ranging in age from ~3.1 to 2.6 billion years).


Teton Range - Grand Teton is the tallest peak at center, topping out at 13,770' elevation.  Looking W.


Mt. Moran (above & below; looking WSW), beautifully reflected in the waters of one of lakes occupying the Jackson Hole Valley.  An obvious dark-colored, subvertical diabase dike is visible on the left side of the summit (see labeled photo below).  A little bit of light-brownish quartzose sandstone caps the peak (again see labeled pic below).  This is the Flathead Sandstone (Middle Cambrian).  Mt. Moran is the only peak in the Teton Range that preserves any Phanerozoic rocks (but not by much!).  The base of the Flathead is the "Great Unconformity", a near-continent wide erosion surface that separates Precambrian basement rocks from (usually) Phanerozoic sedimentary cover.  The Great Unconformity is best exposed & best studied in the Grand Canyon.






The above photo is a view of the Jackson Hole Valley (looking E), as seen from Teton Pass, near the southern end of the Teton Range.  The Jackson Hole Valley (graben) is north-south oriented, about 6 to 12 miles wide, and about 45 miles long.


Going down Teton Pass is a white-knuckle drive.  The town of Jackson (or Jackson Hole) has some of the most expensive real estate in America.



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