Geology of Ruby Falls: J. Hockett
From GeoClasses
by: Jasmine Hockett
Contents |
Geology of Ruby Falls in Lookout Mountain
PICTURE OF LOOKOUT MOUNTAIN FROM: faculty.fortlewis.edu
A well-known mountain most commonly heard of in Martin Luther King's "I have a Dream" speech, resides in East Tennessee. Most of the mountain is made of limestone rock. Over 200 million years ago, a shallow body of water covered a large percentage of Eastern Tennessee. This sea or small body of water was where the limestone of this great mountain was formed. According to Webster’s dictionary, the limestone was created from an accumulation of organic remains, shale, sand, and pebbly sand. It then could be called sedimentary rock. Over the course of years, the sediment toughened and hardened to form the limestone rock which is known as the one and only Lookout Mountain. Over the millions of years of earth's birth, there has been constant movement of it and each piece of mass on it. Everything seems to be growing and moving. The earth, itself, is one large environment of change. Many basic ranges such as oceans,lakes, rivers, volcanoes, islands, and mountains make up the scenary of this geology. Eastern Tennessee, though quite far from the coast now once was near water and in the middle of two plates that were destined to converge and diverge. Many years ago, the convergence of two contenental plates, the North American and African plates, formed a mass of mountains. The tetonic forces produced in the collision caused multiple earthquakes. These earthquakes forced the hardened rock to form Lookout Mountain and many other mountains.
PICTURE OF CONTINENTAL CONVERGENCE WHICH HELPED FORM LOOKOUT MOUNTAIN FROM: commons.wikimedia.org
LOOKOUT MOUNTAIN IS JUST EAST OF CHATTANOOGA,TN. PICTURE FROM: www.united-states-map.org/map/tennessee-map.gif
Picture of Ruby Falls: www.doremi.co.uk
Lookout Mountain would become one of a kind due to the fact that it had a cave and the world's tallest underground waterfall known as Ruby Falls. Ruby Falls is located within the mountain. As the subterranean streams seeped through the crevices, the water dissolved the limestone rock or sediment build-up in a process called chemical weathering. This is the breaking of rocks by wind, water, or plants, aided in the formation of the cave by gradually dissolving the limestone. The waterfall is 145 feet, and the water collects at the bottom of the dome shaped cave in a small pool. The volume of water that comes from the waterfall depends on the amount of rainfall that comes through the cave. The flow from the underground waterfall goes back through the cave and then down another waterfall into the Tennessee River. When the rainfall level is high, the cave has flooded before.
Lookout Mountain also has two caves. The lower cave is about 50 feet above the level of the Tennessee River. It has no formations. This particular cave is not open to the public. The upper cave is open to the public for tours and scientific study. The caves have no connection to each other.
Rock Layers in the Upper Cave
Different rock levels line the walls of Ruby Falls Cave. The cave is made of primarily limestone rock. Over time the limestone and sandstone rock began to crumble which created cracks and crevices. The rock layers the slide past each other causing even more layers. This is part of the early production of the cave.
Most of the layers of rock are in horizontal form. They layers were built over time as sediments, small creatures, sand, pebbly shale, and small creatures compacted on top of each other. This specific time period was known as the Carboniferous Period which occurred at the end of the Paleozoic Era. This specific era was the oldest era in geologic time. It occurred before dinosaurs, mammals, and birds had ever even roamed the face of the earth.
Earthquakes helped to bend and fold and shape the rocks into such creative shaped layers. Since the rocks emerged from an ancient sea bed, cracks and crevices were formed. Scientists call these cracks and crevices faults or joints.
Three Most Common Rock Formations in Ruby Falls Cave
The most common formations found in the Ruby Falls Cave are stalactites, stalagmites, and columns. The formations are formed from mineral water such as calcium carbonate dripping down from the ceiling. The different rows of stalactites found on the ceiling are found along joints and crevices in the limestone.
The formations of cave deposits also known as speleothems on the walls, floor and ceiling of the cave is a very slow process. The rate of growth of the formations varies. Most rates vary in growth from one cubic inch every one hundred to one hundred fifty years. With little moisture present in the caves, the formation growth is relatively dry. The temperature in the Ruby falls cave is about 60 degrees.
Stilactites
The pictures above are of stalactites. They grow from the ceiling from dripping mineral water. They tend to grow in clusters or in rows. As minerals build up slowly, a stilactite is being formed. The start out as capillary tubes which are also known as soda straws. They tend to be hollow in their beginning stages. As time goes on, the tip of the capillary tube closes and it becomes a stalactite. It then collect more and more minerals making it wider.
Stilagmites
The pictures above are of stalagmites. They tend to look like cactus or candles. They grow upward from the floor of the cave. Over time they can grow fairly high. They almost always form under stilagtites in a cave. Stilagmites are formed when minerals are deposited on the floor and collected over time.
Columns
The pictures above are of columns. They were formed where stalagmites and stalactites grow together. All of these formations are made up of calcium carbonate that has crystallized as calcite.
Other Formations in Ruby Falls Cave
Some other types of formations that can be found in Ruby falls cave are flowstone, curtains, and helictites.
The following are examples of flowstone. The white icing look is created by calcium deposits.
Flowstone is thin sheets of calcite on the walls or rock levels or ledges of the cave. Most flowstone is formed from precipitation along a flat surface. The water runs along a flat surface before falling. The flowstone eventually builds up and becomes more rounded as it gets thicker.
Curtains
Curtains are drape-like formations formed by water coming through small cracks and crevices in the ceiling. The water then evaporates before it has the chance to fall. This allows thin strip of calcite to build up. They are very similar to flowstone.
Helectites
Helectites are common in Ruby Falls. They are a form of stalactites. They grow in regard to gravity. The crystals of calcite are not arranged in a specific arrangement. This causes the formations to assume a curved shape. They generally grow in the direction of the ceiling.
Interesting Extras in the Cave
Moisture in the Ruby Falls cave comes mostly from the waterfall. There are small streams and puddles throughout the cave that often add to flooding during great rains. They do help to keep the whole cave from flooding. When groundwater flow starts to fill the caves these streams serve as drainage systems to help control the water.
Suprisingly, moss was growing in the cave. In order for moss to grow, it needs acurate sunlight. Moss are small soft plants. They generally grow closely together in clumps or mats in damp locations. They do not produce any sort of flowers or seeds. The display lights along the cave paths and the minerals in the atmosphere helped to produce the moss in such an unordinary area.
This is a rather large stilactite. It is known as the elephants foot. It seems to get wider as the years pass by. One day, it will grow into a column.
Extra Websites
More in formation about Ruby Falls: http://en.wikipedia.org/wiki/Ruby_Falls
Planning an educated trip: http://www.rubyfalls.com/history4.htm
