Coordinates listed are for parking. Outcrops are within 100 feet.
PERMISSION:
This earthcache was placed with permission from the Chief of Resource Management and Interpretation, Blue Ridge Parkway.
EARTHCACHE REQUIREMENTS:
Each cacher must send in their own answers when logging this find. After you arrive at the overlook, enjoy the view and what you will bring home with you through this experience. Review the materials below and answer by message/email the questions to the best of your ability. Enjoy your time at this beautiful location. Please follow all logging requirements.
WEATHERING:
Weathering in geology is the breaking down of rocks, minerals and soils through contact with water, biological organisms and atmospheric gases. Weathering occurs essentially unnoticed, not to be confused with erosion. All rocks weather over time with grains of sediment falling out. Cracks can develop on the surface or within the rock formation. Weathering can cause rocks to buckle, fracture and crumble. There are several different types of weathering--mechanical, chemical and organic.
MECHANICAL WEATHERING:
Mechanical weathering occurs when rocks break apart with no change in their chemical composition. Individual particles and fragments that have been weathered away by a mechanical process still holds on to the rock's original characteristics. Mechanical weathering involves five significant processes that will physically cause the rocks to break down into sediment or particles. This include abrasion, crystallization of ice, thermal fracture, hydration shattering and exfoliation. Abrasion occurs as a result of the grinding against other rock particles. Crystallization of ice can exert enough force to break/fracture a rock. Thermal fractures occur due to significant changes of temperature. The Effect of water, hydration, for the most part affects the minerals of clay. Exfoliation happens when rock is unearthed after it is formed.
CHEMICAL WEATHERING:
Decomposition or decay of rock is involved with chemical weathering. The chemical composition of the rock is altered through hydrolysis, oxidation, hydration or carbonation. Chemical weathering changes the rock's composition towards surface minerals, usually affecting the minerals that were unstable to begin with.
ORGANIC WEATHERING:
Organic weathering is usually referred to as bioweathering or biological weathering. It involves contact usually contact with plants. If an animal digs in the area, plants/seeds may come in direct contact with the rock and begin growing roots contacting the rock. Those same roots or seeds may have been carried to these rocks by wind, rain or other source. Acids from plants may also contribue to the dissolution of rock. Lichens work like little chemical factories and do their part to weather rocks and build soil. Mosses can also contribute to this through retaining moisture, allowing that moisture to freeze and thaw. Moss also helps build soil and footholds for other vegetation that develop root systems into cracks, continuing the process. Organic weathering's process does not stand alone, but is a combination of mechanical and chemical weathering factors, with plant vegetation being a major influencer in this process.
DIFFERENTIAL EROSION:
Differential erosion is caused by the differences in the resistance and hardness of surface matetials. Softer and weaker rocks are more rapidly worn away. Harder and more resistant rock remain to form ridges, hills or mountains. Unusual formations and remnants are often the result of this process. Erosion results in the transportation of loosened or altered material residue which moves across the surface of Earth being carried by water, ice, wind, gravity leading to an eroded state. Weathering is necessary for erosion but a rock may continue to weather without experiencing erosion.
FAULTS:
Faults may be vertical, horizontal or inclined at any different angle. Even though the inclination angle of specific fault plans are relatively uniform, it may be considerably different in its length from one place to another. Faulting occurs as rocks slip past each other. The overlying rock in the fault plane is referred to as a hanging wall or headwall. The block beneath it is referred to as a footwall. The fault strike is the direction of the line of intersection between the Earth's surface and the fault plane. The dip of a fault plane is the angle of inclination measured from the horizontal.
NORMAL FAULT:
Normal dip-slip faults result from vertical compression as the Earth's crust lengthens. Movement is downward caused by tension where two blocks of rock are pulled apart. The hanging wall slides down relative to the footwall. Normal faults are common. They bind many of the mountain ranges of the world and many of the rift valleys found along the spreading margins of tectonic plates.
REVERSE FAULT:
Reverse faults results in movement that is upward caused by compression. Reverse dip-slip faults occur as a result from horizontal compression forces causing a shortening/contraction of the crust of Earth. The hanging wall moves up and over the footwall.
LATERAL FAULT:
Lateral faults result in the forward movement caused by horizontal compression. Lateral faults are also referred to as a strike-slip fault, transcurrent fault or wrench fault. It is a fracture inside the rocks of Earth's crust resulting in rock masses slipping past one another, parallel to the strike. These faults result from horizontal compression, but release their energy by displacing rock in a horizontal direction almost parallel to the compressional force.
OBLIQUE FAULT:
Oblique faults result from movement at an angle caused by a combination of compession and shearing. They have simultaneous displacement either up or down the dip and along the strike. Displacement of the blcoks on the opposite side of the fault plane is usually measured in relation to sedimentary strata or other types of stratigraphic markers like veins and dikes. Movement could be rotational along the fault with blocks that were offset rotating relative to each other.
THRUST FAULT:
Thrust fault is the movement where lower strate are pushed up and over higher strata caused by compression. They often place older rock above younger rock. It is a type of reverse fault with a dip of 45 degrees or less. The fault plane's angle is lower, less than 15 degrees from the horizontal. Displacement of the overlying block is tremendous, frequently in the kilometer range.
OVERLOOK:
Table Rock Mountain is an erosional remnant created during Alleghanian mountain building. A fault resulted in quartzite (hardness 7) rocks of the Chilhowee Group underlain by biotite granitic gneiss (hardness less than 7).
RESOURCES:
A Geologic Adventure Along The Blue Ridge Parkway in North Carolina by Carter/Merschat/Wilson....2001
Congratulations to David&Diana for being FTF on July 3, 2022.
QUESTIONS TO ANSWER:
1. Referring to the above materials and based on the visually striking appearance of this formation, what forces of nature gives Table Rock it's unique appearance?
2. By observing Table Rock Mountain, how do you think that erosion and weathering has contributed to it's unique appearance and where do you observe vegetation or lack of?
3. From the diagram of fault types, describe why you think Table is a prime example of one type in particular.
4. Post a picture at or near the coordinates (you do not have to be in the picture unless you want to). This is your log signature.
GINGIN'S MESSAGE:
T - Tread lightly with the footsteps you make
A - Always doing the right thing for this land we visit
B - Being responsible for your actions, little or small
L - Leaving no trace, doing one last check
E - Enjoy the view, the air and fragrances aloft
R - Rustic majesty, forever may you stay...your land, wildlife, sky and waters
O - Our mind, heart and being lifted and renewed
C - Caring to be sure we have this land for all future generations
K - Keepers of this land we all must be, our time short but our impact forever.
M - Mother Earth, always present, keep her healthy
O - Overlooking the valleys, mountains and distant places
U - Understanding that we want our future generations to see what we see now
N - Noticing the small and grand things, creatures and land
T - Trust in each to leaving plants untouched for others to enjoy the same
A - Attaining peace within that the Blue Ridge affords each
I - Individual expectations within moments of views not seen other than this exact location
N - Needing to safeguard this fragile land for those yet not breathing this wonderful air.