Geology of Great Smoky Mountains National Park

A photograph taken of Nymph Lake in Rocky Moun...

A photograph taken of Nymph Lake in Rocky Mountains National Park. (Photo credit: Wikipedia)

The Great Smoky Mountains National Park is just an awesome place to visit, part of the majestic Appalachian Highlands offering a wild-land sanctuary which preserves possibly one of the finest examples in the world of a temperate deciduous forest. Why “Smoky”? Well, the name comes from the mysterious smoke-like haze which envelopes the mountains stretching far onto the horizon in great, sweeping troughs.

The Great Smoky Mountains National Park is one of the few places on earth where the unspoiled forests are remarkably similar to the ones first found by the early pioneers, there are restored log cabins dotted around the park which are a great reminder of the people who first managed to survive in this wilderness wonderland. The rich and fertile soils, along with plenty of rain (don’t forget your rain jacket) has encouraged a great diversity in flora and fauna, with more than 1,500 different kinds of flower plants. Broad leaf trees dominate the coves, and conifer forests spread high along the crests.

As with many national parks, the Great Smoky Mountains has a different story to tell at different times of the year. During the springtime of April and early in May there are lots of wildflowers and migrating birds in the park, the early summer months bringing rhododendrons which bloom in all their glory, and the fall (considered by many people to be the best time of year for the ultimate Great Smoky Mountains National Park experience) the colors are at their peak around mid October. Winter in the Great Smoky brings unpredictable weather, rolling fog and blankets of frost go towards making a very different type of experience.

High-elevation spruce-fir forest on Clingmans ...

High-elevation spruce-fir forest on Clingmans Dome.

But What About The Geology of Great Smoky Mountains National Park . . .

I know, I got all poetic and side-tracked, right, so where did the Great Smoky Mountains come from, how were they formed?

The majority of the rocks which form the Great Smoky Mountains are sedimentary, formed by an accumulation of clay, sand, silt and gravel, with the oldest of these rocks being formed a startling 800 – 545 million years ago. Large amounts of these stuff was washed down into the lowland basins from the highlands, some of the old highland rocks in the Great Smoky Mountains National Park are around one billion years old . . . yikes! As more and more sediments were deposited in this way, they eventually became cemented together and created rock layers, some of which are over nine miles thick . . . double yikes!

Fast forward to around 310 and 245 million years ago, when the eastern edge of the tectonic plate of North America collied with the tectonic plate of Africa creating a super continent named Pangaea. Now, these continental collisions might only happen at a few inches per year, but we’re talking millions of years here remember . . . evidence of these early geologic events can be found in the rocks at Great Smoky Mountains. During one early collision there was tremendous pressure and heat generated which metamorphosed the sedimentary rocks of the Smokies. Sandstone became meta-sandstone, shale became slate.

Eventually the entire Appalachian mountain chain was created with a massive uplifting episode, these mountains were probably lots higher than they are nowadays, maybe even as high as the Rockies. As the tectonic plate of Africa continually pushed against the tectonic plate of North America those original layers were bent, broken and folded by faults, causing huge masses of the old, deeply buried rocks to be pushed northwestwards and up, over the younger, higher rocks . . . this is known today as the Great Smoky Fault.

Erosion is a fact of life, and as the mountains were eroded and worn away the layers of rock which were the most resistant remained to form the very highest peaks of the Smokies, like the meta-sandstone which is evident at the top of Clingmans Dome. The majority of the wonderful waterfalls were created by down-cutting streams encountering layers of super resistant meta-sandstone eroding much more slowly than the meta-siltstone or slate. Geologists reckon that the Smokies are being eroded at a rate of around two inches every thousand or so years . . . not sure how they worked that one out but who am I to argue!

Anyway, that’s the story of how the Great Smoky Mountains came to be . . . . kind of!

I wish I was there now . . . right NOW!

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