A list of 3 Historical Structures You’ll See Along Roaring Fork Motor Nature Trail (smokymountainnationalpark.com). The Roaring Fork Auto Tour is so lovely we did it twice.
Roaring Forks History
Blue Ridge Mountains
Roaring Forks Water
We drove the Roaring Forks Motor Tour twice during our stay near Gatlinburg, Tennessee by the Great Smoky Mountains National Park (U.S. National Park Service) (nps.gov) part of the Blue Ridge Mountain system.
Here are a few images made of the water in the air and on the ground during the first tour.
Waterfalls – Great Smoky Mountains National Park (U.S. National Park Service) (nps.gov)
Skyline Fog
An early morning drive in the Blue Ridge Mountains. By the time we got to I-81 on the drive south to the Great Smokey Mountains the fog lifted.
We saw many deer and hundreds of squirrels. Marc had to keep braking for them. Squirrels often get scared then run in the wrong direction – towards the car.
More Shenandoah
I never tired of the views form Skyline Drive.
Stony Man 2 of 2
Quotes about the Geology:
Stony Man Mountain itself is composed of ancient basalt (greenstone) that was metamorphosed through heat and pressure. The greenstone lava flows, which are approximately 570 million years old, now form the sheer, jagged cliffs of Stony Man and other peaks within the park. These flows, stacked one atop the other, create a unique topography of sheer cliffs and flat benches, contributing to the distinctive landscapes of Shenandoah National Park
The Geological Formation Of Shenandoah
The geologic story of Shenandoah National Park began 1 billion years ago. Molten magma, miles beneath the earth’s surface, slowly solidified to become the “basement rock,” or core, of what we know today as the Blue Ridge Mountains. For the next 500 million years, erosion and the uplifting of the earth’s crust exposed the granitic basement rock. You can see the granite component of this rock in Old Rag Mountain and its surroundings.
Over millions of years, the uplift of the earth’s crust formed deep cracks in the granite, which led to volcanic activity. For centuries, molten basaltic lava burst forth and poured over the land, forming a smooth, flat plain called the “Catoctin Formation.” (The bedrock underlying Big Meadows was formed by at least 12 of these lava flows which, collectively, are approximately 1,800 feet thick.) The cooling and contraction of the lava produced a network of polygonal cracks, or columnar jointing.
When continental drift (the separation of the Americas from the continents of Europe and Africa) began, about 600 million years ago, it formed a broad, shallow depression from Alabama to Newfoundland. Then, for 300 million years, an ancient sea flooded the area that is now the Appalachian Mountains. Layers of water-borne sediments accumulated on the ocean floor, followed by limestone sediments composed of fossilized marine animals and shells. The weight and resultant heat caused by the sediments eventually compressed the two layers into metamorphic rock.
As a result of the eons-old shifting of the earth’s tectonic (or crustal) plates, North America and Africa collided. This re-elevated and fractured the sea floor, causing the older, underlying layer of metamorphic rock to tilt upward and slide over the younger layer creating a towering mountain range that we call the Appalachians. The process occurred so slowly that even if geologists had been present, they would not have known that it was occurring. The new Appalachians probably looked more like the present Himalayas than the rounded mountains we see today.
The powerful forces of wind, water and frost have worn away the Appalachians for nearly 250 million years. These forces continue to create and refine the spectacular scenery of Shenandoah National Park. Water runoff, as demonstrated by the “500-year” rainstorm of June 1995, has carved the mountains’ distinctive alternating pattern of ridges and valleys. As you explore the park, look for signs of its geologic history and for how wind, water, frost and ice continue to sculpt the land.
Reference: History of Shenandoah APA Citation: Formation of the Shenandoah Region. Retrieved from OhRanger.com
In-Depth Geological Studies: USGS: New Geologic Map of the Shenandoah National Park Region
Geologic mapping in the Shenandoah National Park region of Virginia was conducted from 1995 to 2008 as part of a cooperative investigation between the USGS, National Park Service, College of William and Mary, and George Washington University, through the National Cooperative Geologic Mapping Program’s Educational Mapping component.
Available Downloads: Map PDF (37.8 MB) and Pamphlet PDF (103 pages; 1.7 MB). 2009, scale 1:100,000. USGS: A Hiker’s Guide to the Geology of Old Rag Mountain
Stony Man 1 of 2
Stony Man (U.S. National Park Service) was the only short almost level 1.6 mile round trip hike that we did. The drizzly mourning cleared up by the time we go to the summit. The views were worth it.
Shenandoah Monday 4
End of day one in the Shenandoah’s. There are so many overlooks with gorgeous views. We stayed for 3 days in one of the old rustic cabins at the Skyland Hotel in the Park. There was only a trickled of water in the shower and it was off the grid. The Wi-Fi was out the whole week. The food at their “fancy” restaurant was awful. The best thing was the scenery.
The Blue Ridge Mountains get their distinctive blue appearance from a blue haze…
Vegetation and Volatile Organic Compounds (VOCs):
The trees in the Blue Ridge Mountains release fine mists of volatile organic compounds (VOCs) into the air. Trees release a hydrocarbon called isoprene as a way to protect themselves from excess heat. When isoprene is released into the atmosphere, it interacts with other molecules, creating the characteristic haze that gives the Blue Ridge Mountains their bluish hue.
Scattering of Blue Light:
The VOCs released by trees, including isoprene, react with natural ozone molecules already present in the air. These reactions lead to the formation of new particles, which scatter blue light waves from the sun. As a result, when you look at the distant Blue Ridge Mountains on a clear day, they appear covered in a “soft dreamy blue haze” due to this scattering effect.
Shenandoah Monday 3
I stitched the panoramas.
The Blue Ridge Mountains, located in the southeastern United States, are a stunning range known for their rugged beauty and rich geological history. Let’s delve into the fascinating rocks that form this majestic mountain system:
Metamorphic Rocks:
- The Blue Ridge Mountains are primarily composed of highly deformed metamorphic rocks. These rocks have undergone significant changes due to heat, pressure, and tectonic forces over geological time.
- Common metamorphic rock types found in the Blue Ridge include:
- Schists: These are foliated rocks with mineral grains aligned in parallel layers.
- Gneisses: Gneisses exhibit alternating light and dark bands due to mineral segregation during metamorphism.
- Slates: Slates are fine-grained metamorphic rocks that often split into thin sheets.
- Quartzites: Quartzites are extremely hard rocks formed from the metamorphism of sandstone.
- The metamorphic processes responsible for shaping these rocks occurred during various orogenic events throughout the Precambrian and Paleozoic eras.
Geological History:
- The Blue Ridge region experienced multiple tectonic events, including continental collisions, which compressed and metamorphosed the rocks.
- During the Paleozoic, the Blue Ridge and Piedmont regions were pushed westward, resulting in folding, faulting, and uplift.
- The Brevard Fault Zone, spanning from Alabama to Virginia, marks the boundary between the Piedmont and Blue Ridge areas. Along this fault zone, rocks were crushed and ground by immense pressure, creating cataclastic gneisses, schists, and phyllonite.
Rock Types:
- Granitic Charnockites: Ancient granitic charnockites are prevalent in the Blue Ridge Mountains.
- Metamorphosed Volcanic Formations: These include rocks that were once volcanic in origin but have since undergone metamorphism.
- Sedimentary Limestone: Some limestone formations are also present in the region.
Source: Conversation with Bing, 5/2/2024
(1) Rocks of the Blue Ridge and Piedmont — Earth@Home. https://earthathome.org/hoe/se/rocks-brp/.
(2) Blue Ridge Mountains – Wikipedia. https://en.wikipedia.org/wiki/Blue_Ridge_Mountains.
(3) Blue Ridge Province – U.S. National Park Service. https://www.nps.gov/articles/blueridgeprovince.htm.
(4) What rocks are found in Blue Ridge? – NCESC. https://www.ncesc.com/geographic-faq/what-rocks-are-found-in-blue-ridge/.
