Researchers have found that those picturesque mountain streams we admire don't just burble randomly down the hillside- they actually march to the measured cadence of their own drummer. Scientists have discovered that like their flatland cousins, mountain streams meander too. It's just that they meander vertically, dropping from pool to pool at a rhythmic, periodic rate. Scientists don't fully understand the energetics and form-process interactions of high-gradient mountain streams.
Mountain streams are believed to be organized in a regular, periodic pattern. Spectral analysis focusing on the pools and rocky drop-downs streams create in their beds as they move downhill has shown that stream step-pool sequences proceed in a rhythmic, staircase-like pattern. Mountain streams work to accomplish different tasks, moving rocks from pebbles to heavy boulders. Mountain streams work to accomplish different tasks, moving rocks from pebbles to heavy boulders.
Confined by narrow valleys, mountain streams can't move laterally. They can only move vertically, for the most part, and this takes away a degree of freedom in their ability to adjust to energy conditions in the stream system. Researchers say the steepness of the stream's course gives them a high level of energy, which they must regulate stating lowland streams manage their energy more uniformly and efficiency through meandering over the face of the landscape, but mountain streams can only adjust vertically, so they create step-pool sequences to dissipate energy.
The City of Gatlinburg lies within the Appalachian Blue Ridge geologic and physiographic province. The highest mountains in eastern North America occur in the Blue Ridge province, and some of the highest peaks in this province are in the adjacent Great Smoky Mountains National Park. The oldest rocks in the Blue Ridge province are at least 1 billion years old and consist of metamorphosed sedimentary and igneous rocks. These Proterozoic rocks form the core of the ancient Appalachian Mountains. Sediments deposited over these older rocks form the majority of rocks in the Great Smoky Mountains National Park. The oldest sedimentary rocks consist of vast amounts of clastic material that washed down into lowland basins from adjacent highlands.
Geologists say the surrounding mountains may have been much higher than they are today, with elevations perhaps similar to the present-day Rocky Mountains. As the continents collided, the original horizontal layers of rock were bent or folded and broken by fractures and faults. Tremendous forces caused huge masses of older rocks to be pushed westward, up and over younger rocks, along nearly flat-lying faults. Older rocks have washed into present day stream beds. The oldest rocks exposed in the Mount Le Conte area are meta sandstone and meta siltstone. Today they form ledges and falls in mountain stream beds below Mount Le Conte. Car-sized boulders seen in some mountain stream locations today probably were deposited on the slopes and have been exposed and reworked as streams erode down into the older slope deposits and debris flows down from the higher elevations as rhythmic pool sequences continue to form throughout time.
Mountain Streams are a living landscape and have been throughout millions of years. Here, boulders and cobbles of mostly meta sandstone have been deposited down slope by gravity and some have modern streams that periodically flow through them and modify the landform and deposit. Some of the rock deposits you see here are within site of the bedrock source while others are found miles away from the originating outcrop.
To see a mountain stream in action and witness it’s rhythmic descent from the lofty mountain tops, visit The City of Gatlinburg’s Myanott Park. This city owned facility affords visitors the chance to get up close with a picturesque mountain stream and study it’s dynamic and ever changing spectacle. Bring a picnic lunch and relax to it’s peaceful sound as you ponder the geologic wonder that this and every other mountain stream truly is!
For credit for this earth cache- make the simple measurements and calculations below and provide the answers in an email to us. Then post a picture of the geologic setting surrounding the coordinates with your log.
1. What is the elevation reading at the coordinates provided for the listing?
2. Travel to (35 42.11) (83 30.85). What is the elevation reading here?
3. What is the difference in elevation from the original coordinates and the second way point? That is how much the elevation in stream bed has changed in such a short distance! Such continual change in elevation makes the water velocity quite an erosive agent that exposes older rock more and more over time.
4. Estimate the width of the creek at the second waypoint.
Through eons of time the eroding action of running water, cutting numerous valleys and ravines, has had much to do with establishing the present-day topography. The sight, sound, and feel of clear, cool mountain streams that tumble down slope as cascades and waterfalls offer a chance to become one with geology in action and get up close with the forces of nature!