John Rock and Looking Glass Rock

Overlooking Looking Glass Rock from the rock face of nearby John Rock

I went on a hike with some friends to the summit of John Rock in the Pisgah National Forest yesterday afternoon.  There was a winter storm in North Carolina the previous day, but the temperature got up to 47 °F which was warm enough to make almost everything melt by the time we started hiking near 1:00 PM.  The nearby Davidson River was swollen with the new snowmelt.

Geologically speaking, Looking Glass Rock is a pluton.  A pluton is a big ball of granite which would have become a volcano if it had not cooled before reaching the surface.  Volcanoes occur when at convergent boundaries when crust subducts and melts underneath the surface.  This melting crust forms magma (the same thing as lava, but lava occurs above the surface whereas magma occurs underneath the surface) which is less dense than its surroundings and rises toward the surface.  What are now the North American and African Plates used to be much closer together and were actually at a convergent boundary.  This convergent boundary formed the Appalachian Mountains when the oceanic portion of the plate subducted.  This continental collision formed the Appalachian Mountains which still exist from Alabama northeast up to Maine in the eastern United States.  We were so excited to view Looking Glass Rock from John Rock because the name “Looking Glass” is comes from how ice appears similar to a mirror when the sun reflects on it.  The warmer temperatures and exposure to sunlight actually made Looking Glass Rock not reflective, but John Rock’s pluton was mostly shaded and still covered in a layer of ice.

I am the biggest fan of hiking and geology in my group of friends by far, so I chose the hiking location and plan for the day.  Basically, they told me they would be up for going wherever I wanted to go.  The Pisgah National Forest is one of my favorite places for hiking because it is such a large area which is well maintained and protected.  My interest in John Rock and Looking Glass Rock came because of a lesson in class we had about the history of the Appalachian Mountains.  I wanted to know if I could see any of these ancient volcanoes which occurred because of the convergent boundary which originally formed these mountains.  Looking Glass Rock and John Rock would have been volcanoes, but the magma in both of these areas cooled too quickly before forming into volcanoes.  The Appalachian Mountains were once connected to the African continent, but later broke apart and moved away based on the hypothesis of continental drift.  The dominant force in this area is erosion, but many think that the Appalachian Mountains were once as high as the Rockies.  Veins of quartz were seen in the granite as well as seen along the trail itself.

Many mountain peaks I have hiked to in North Carolina feature granite outcrops, so I find these areas to be particularly interesting and beautiful.  Beacon Heights and Rough Ridge are two favorites.

A view of the mountains taken from the rock face of John Rock

Mountain laurel and rhododendron were everywhere along the trail and even right beside the rock face

Want to go?  Want more information?
http://www.blueridgeheritage.com/attractions-destinations/looking-glass-rock