The Geological Formation of Stone Mountain in Georgia - Essay Example

? A Detailed Research in the Geological Formation of Stone Mountain in Georgia and its surrounding region May The geological history ofGeorgia is exceptionally fascinating. It is divided into five regions; the Piedmont, Ridge and Valley, Blue Ridge, Appalachian Plateau and the Coastal Plains. The position of these regions is best explained through the process of plate tectonic collisions of the continents that built the Appalachian over 300 million years ago. All these plate collisions have also caused other mountain formations like Stone Mountain. It has the world’s largest exposed mass granite and the third largest monolith in the world. The Stone Mountain in Northern Georgia boosts a mysterious history with a lot of unanswered questions. Despite that, Stone Mountain is known today for its beauty and exquisite bas relief. Three figures from the Confederate States of America have been carved here; Stonewall Jackson, Robert E. Lee and Jefferson Davis. Stone Mountain is host to the Stone Mountain Park which is the major tourist attraction there at the site. In addition to that-it plays a major role in Georgia’s eco-system as well as its economy. Thesis Statement: A detailed research into the geological formation, History and economic value of Stone Mountain. 1. Formation of Stone Mountain 2. Most prevalent rock types 2.1 Granite Rock 2.2 Gneiss Rock 3. How old is Stone Mountain? 4. Birth of Stone Mountain 5. Plate tectonics relative to the creation of Stone Mountain 6. Weathering in Stone Mountain 6.1 Physical Weathering 6.2 Chemical Weathering 6.3 Biological Weathering 6.4 Analysis of Weathering in Stone Mountain 7. Types of Rocks in Stone Mountain 8. The Georgia Piedmont 9. Resources in Stone Mountain 1.0 Formation of Stone Mountain Georgia’s geologic formation is extremely fascinating and is suspected to have covered a billion year period. Influenced by different formations and erosions from mountain ranges and geologic events such as severe climatic changes, and volcanic eruptions and flooding -Georgia’s geology still sparks mysterious questions. The compilation of these geologic events has led to the formation of a historical landmark known today as Stone Mountains. With reference to Larry Worthy’s article ‘Stone Mountain Natural History’ (exclusively for About North Georgia, 1994-2011) Stone Mountain at its highest point stands a mighty 1683 feet above sea level and sits on the western edge of a large belt of Lithonia Gneiss granite although the younger intrusive granite that comprises the mountain is entirely different from Lithonia granite. Commonly referred to as a granite dome manadnock, Stone Mountain’s development disseminated through several counties and provides a significant amount of bas relief. The formation of the Stone Mountain is still pondered by many geologists with a lot of unanswered questions. However, based on reviewed literature it is safe to say; water, desert like conditions and glacial features played a vital role in its formation. First up, the Stone Mountain in Georgia was formed during the last stages of the Alleghenian Orogeny which also created the Appalachian Mountains. Technically speaking, the ‘stress’ and ‘pressure’ from the Alleghenian Orogeny caused huge uplifts of land in the Northern Georgia region to form mountains. As far as water impacting Stone Mountain’s formation goes; many geologists believe that the Piedmont was higher than the mountain at one point and as millions of years passed the water slowly eroded leaving so much of the Stone Mountain granite exposed. On the other hand, in the Researcher’s opinion, its formative exposure could be due to heat and pressure inside the earth alongside the divergent occurrences of plate tectonic processes. In addition to that, the desert like conditions in the area help to define the mineral composition of the different rock types found in the region. 2.0 Most Prevalent Rock Types on Stone Mountain Rocks from the Stone Mountains belong to the three major classifications according to the rock cycle. However, the two most popular categories of rock are metamorphic and igneous rocks. One common rock from the metamorphic group is the Gneiss rock whilst the Granite is a common rock example from the igneous group found at the site. 2.1 Granite Rock Granite is a type of intrusive and igneous rock which is usually semi-coarse or coarse in texture. Stone Mountain is sometimes referred to as the pink granite. The Granite is pink in color because of its mineralogy and chemistry. Reviewed Literature dictates that there are at least two known ways for the composition of Stone Mountain’s Granite. Creationresearch.org cites Whitney et al (1976, pg 1071) “in terms of mineralogy and major and minor-element chemistry, Stone Mountain Granite has a highly differentiated composition brought about by fractional crystallization and fractional melting.” According to creationresearch.org it is highly composed of feldspar, Quartz, microcline and muscovite with smaller proportions of biotite and tourmaline. Further study also shows that Xenoliths (foreign pieces of rock entrained in the magma) are found in the granite. In addition the Xenolith from the Stone Mountain Granite is composed of two types of metamorphic rocks-Gneiss and amphibolite xenoliths of the country rock torn from the conduit as the granite ascended through the earth's crust. 2.2 Gneiss Rock On the contrary the Gneiss Rock is a metamorphic rock with an intriguing banding. To a person with limited knowledge on Geology or a related subject, they will classify the rock with parallel and somewhat irregular banding which has little tendency to split along the planes-which is technically correct. According to the Britannica online encyclopedia Gneiss is composed of an abundance of Quartz and Feldspar. The same source also dictated that “the mineralogy of a particular gneiss rock is a result of the complex interaction of original rock composition, pressure and temperature of metamorphism, and the addition or loss of components.” 3.0 How old is Stone Mountain? Stone Mountain is estimated to be 350 million years old. Its age has always been referred to the last stages of the Alleghenian Orogeny which was the last time North America and North Africa collided in the late Paleozoic time. The Alleghenian Orogeny is referred to as a mountain building event. According to the online Britannica encyclopedia, the Alleghenian Orogeny occurred almost at the same time of the Permian Period which created the Appalachian Mountains. It was also declared by the said source that the Alleghenian Orogeny produced the compressional folding and faulting of the Ridge and Valley Province and Blue Ridge regions in Georgia. 4.0 Birth of Stone Mountain Larry Worthy’s article reveals that Stone Mountain was formed during some intensive folding and faulting that created Blue Ridge Mountains (even though it’s not a part of its range). The article further went on to state that Stone Mountain was formed by magma deep inside the earth, which then forced its way out of the earth's molten center. Prior to the molten rock hitting the air it stopped, forming the west side of the "pluton." Several attempts at eruption (breaking through to the surface of the earth) also failed, but indeed added to the size of the dome from west to east. After the pluton formed, it began to cool. Technically since it was formed from magma-the most suitable geological event that could have fostered its creation was a volcano. 5.0 Plate Tectonics relative to the creation of Stone Mountain With reference to an online dictionary, the term ‘plate tectonics’ refer to a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on plastic asthenosphere more or less independently to collide with, slide under or move past adjacent plates. Many geologists believe that the continents were once a part of a large land mass called PANGEA and they split and drifted away from each other. This splitting and drifting process produces the presently known continental shapes. Sir Francis Bacon was the first to observe that the continents looked like a jigsaw puzzle. The most known role of plate movement is the development of mountains as such plate tectonics played a major role in the formation of Stone Mountain through various plate collisions that occurred during the Alleghenian Orogeny and even before which also created other mountains. 6.0 Weathering in Stone Mountain Weathering may be defined as the process that breaks rocks into smaller pieces. It is only natural for rocks to undergo this process at some point which is classified under three categories. 6.1 Physical Weathering Quite often the process of mechanical weathering that occurs through a freeze-thaw procedure. This procedure occurs when water gets into the tiny cracks in the rocks, when the water freezes the crack expands and once the procedure is repeated it will result in the rock breaking away. 6.2 Chemical Weathering Very straight forward, this type of weathering occurs when rock is chemically attacked; such as when acid rain attacks limestone causing it to be broken down. 6.3 Biological Weathering Undoubtedly the most natural of the three- biological weathering causes rocks to be weak as they’re being broken down by animals and plants. In other words let’s say there is a giant tree on a rocky hill or mountain and the roots are so big it causes the rocks to split-this is an example of biological weathering. 6.4 Analysis of Weathering in Stone Mountain The above mentioned types of weathering can significantly affect the appearance of a geological structure. With reference to Stone Mountain in Georgia, rocks there have undergone and are still undergoing some amount of weathering-particularly physical weathering. Erosion being classified as a type of physical weathering is responsible for changes in the appearance in the rocks on Stone Mountain. Soil erosion there causes the surface rock to strip away in a way that causes them to be exposed over a period of time. The now exposed rocks which were once buried deep in the earth are no longer subject to the pressure which would have affected them being at a greater depth. . The freedom from pressure causes underlying rocks to expand upwards and develop fractures parallel to the present ground surface. These newly formed structures are now known as exfoliated sheets. 7.0 Types of Rocks in Stone Mountain The three major rock groups; metamorphic rocks, igneous rocks and sedimentary rocks can all be identified on and around the Stone Mountain region. As mentioned before, the Piedmont (the area surrounding the Stone Mountain) is comprised of mostly metamorphic rocks. The USGS’ website declared that the Piedmont is also comprised of igneous rocks. Both the metamorphic and igneous rocks were derived from the re-crystallization of ancient (300-600 million years old) sediments that were once deeply buried and subjected to high temperatures and pressures. They were then re-exposed during a collision between Africa and North American continents about 300 million years ago. 8.0 The Georgia Piedmont The Georgia Piedmont is situated between the coastal plain and the mountains in the Stone Mountain region in Georgia. It is a homely habitat for such animals like; opossums, squirrels, Canada geese, ducks, woodpeckers, blue jays and owls. It is a forestry that host trees like; pine trees, oak trees and hickory trees. The area surrounding the Georgia Piedmont consists of mostly moderate to high grade metamorphic rocks which includes; schists amphibolites, gneisses, and migmatites and igneous rocks like granite. The Piedmont’s topography comprises of rolling hills even though faulting which caused the isolated granitic pluton to rise above the Piedmont’s landscape and produce prominent features like Stone Mountain. In other words the Piedmont region played a part in the creation of Stone Mountain through the faulting caused by consuming boundaries (pushing together) of plates in that area. 9.0 Resources in Stone Mountain There is a variety of resources in the Stone Mountain region-some in abundance and others in scarcity. Oil and natural gas is one such example of resources in scarcity. On the other hand for abundant resources-there is an abundance of ground water located in the coastal plains. With reference to the University of Georgia’s Department of Geology-the less porous rocks of the other regions of Georgia provide less groundwater, but the aquifers of the coastal plains dispense a surplus of ground water for domestic consumption, industry and agricultural irrigation. The coastal plains are also host to one of the most significant and economic mineral known as Kaolin, a clay rich rock mined near the Fall Line. This rock holds a strong economic value in the region. Kaolinite which the dominant mineral of kaolin, it is used in a variety of industries from paper to pharmaceuticals. Secondly, the Piedmont mineral resources include hard crushed stone, which is quarried by such companies like Vulcan Materials. In addition to that Stone Mountain itself was mined for Granite which is probably the most abundant which is used in a variety of buildings. All the above mentioned resources play a vital role in the economy of Stone Mountain and the surrounding region of Georgia. Not only that, these resources aid in improving the quality of life of the inhabitants. Works Cited Page “Alleghenian Orogeny”, (2011), Encyclopedia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/16026/Alleghenian-orogeny “Description of Stone Mountain”, (2011), Stone Mountain Entertainment, Retrieved from: http://stonemountain.com/description “Georgia Geology”, (2011), www.gly.uga.edu, retrieved from: http://www.gly.uga.edu/default.php?PK=0&iPage=5#Links Gore P. “Geologic History of Georgia: overview”, (Jul 1, 2006), georgiaencyclopedia.org, retrieved from: http://www.georgiaencyclopedia.org/nge/Article.jsp?id=h-3510 “Gneiss Rock”, (2011), Encyclopedia Britannica, Retrieved from: http://www.britannica.com/EBchecked/topic/236276/gneiss Worthy, L “Stone Mountain Natural History”, (2011), ngeorgia.com, Retrieved from: http://ngeorgia.com/ang/Stone_Mountain_Natural_History Read More