America's Volcanic Past
|"Though few people in the United States may actually experience an erupting volcano, the evidence for earlier volcanism is preserved in many rocks of North America. Features seen in volcanic rocks only hours old are also present in ancient volcanic rocks, both at the surface and buried beneath younger deposits." -- Excerpt from: Brantley, 1994|
Volcanic Highlights and Features:
|[NOTE: This list is just a sample of various Tennessee features or events and is by no means inclusive. All information presented here was gathered from other online websites and each excerpt is attributed back to the original source. Please use those sources in referencing any information on this webpage, and please visit those websites for more information on the Geology of Tennessee.]|
The Interior Plains:5
The Interior Plains is a vast region that spreads across the stable core (craton) of North America. This area had formed when several small continents collided and welded together well over a billion years ago, during the Precambrian. Precambrian metamorphic and igneous rocks now form the basement of the Interior Plains and make up the stable nucleus of North America. With the exception of the Black Hills of South Dakota, the entire region has low relief, reflecting more than 500 million years of relative tectonic stability.
The Atlantic Plain:5
The Atlantic Plain is the flattest of the provinces. It stretches over 2,200 miles in length from Cape Cod to the Mexican border and southward another 1000 miles to the Yucatan Peninsula. The Atlantic plain slopes gently seaward from the inland highlands in a series of terraces. This gentle slope continues far into the Atlantic and Gulf of Mexico, forming the continental shelf. This region was born during the breakup of the supercontinent Pangea in the early Mesozoic Era.
Precambrian Igneous and Metamorphic Rocks:6
Precambrian Sedimentary and Metamorphic Rocks:6
|Tennessee's Igneous and Metamorphic Rocks|
Tennessee's Igneous and Metamorphic Rocks:6
Extreme eastern Tennessee (Johnson, Carter, and Unicoi Counties): Metamorphosed lavas and tuffs, metagabbro, rhyolites, diorite, granite, granitic gneisses, monsonite, quartz latites, anorthosite and diabase.
Geologists tell us that sections of huge plates forming the crust of the earth have collided violently on numerous occasions in the past. The results are folded-up slabs of crust piled up like a deck of cards or a wrinkled throw rug. This mass of mostly igneous (cooled, molten material) and metamorphic (formed under heat and pressure) rock is the geological foundation of the Appalachians that we see today.
Blue Ridge Mountains -
Blue Ridge National Parkway
Blue Ridge Mountains:3
Most of the rocks that form the Blue Ridge are ancient granitic and metamorphosed volcanic formations, some exceeding one billion years in age. By comparison, humans have been associated with this land only about 9,000 years.
Blue Ridge National Parkway:1
The Blue Ridge National Parkway extends 469 miles along the crests of the Southern Appalachians and links two eastern national parks: Shenandoah and Great Smoky Mountains.
(During the Late Proterozoic Era - 750 to 570 million years ago) ... Large copper deposits formed in the area we now know as Copper Basin, near Ducktown, Tennessee. Geologists think that these ore deposits probably formed from hot fluids escaping from deep within the Earth through vents in this ancient sea floor. Metal-rich "black smokers" discovered recently in the Pacific Ocean off the coast of Washington and Oregon may represent a modern analogy.
Great Smoky Mountains -
Great Smoky Mountains National Park
Great Smoky Mountains:2
The Great Smoky Mountains, the majestic climax of the Appalachian Highlands.
Lebanon Pike across from Mount Olivet Cemetery,
In the yard of the building supply company you can see the residue of ash falls from two of the huge volcanic eruptions that occurred about 455 million years ago. Look for two horizontal bars. Fossil hunting is better a few doors further west on Lebanon Pike. Look for lots of coral along the road going into the quarry.
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