Coordinates 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 beautifiul location. Please follow all logging requirements.
REGIONAL BARROVIAN METAMORPHISM:
Metamorphism occuring over broad areas of the crust is referred to as regional metamorphism. Mostly this occurs in areas that have already undergone deformation during an orogenic event that resulted in mountain belts and subsequently eroded to expose metamorphic rocks. Barrovian metamorphism is the most commonly observed, occuring in areas where intense tectonic conditions associated with major mountain building. It is found in all parts of Earth and produces one of the most common metamorphic rock formations. It is also complex in nature and a very useful metamorphism geologically speaking. As a result, Barrovian metamorphism is of particular importance.
INDEX MINERALS:
Index minerals are so called because they index when, during the metamorphic process, a particular set of temperature and pressure conditions have been achieved. They appear in a set order: chlorite, biotite, garnet, staurolite, kyanite and sillimanite. At low temperatures and pressures, chlorite is the only index metamorphic mineral that appears in the rock. As temperature and pressure increases, other minerals appear. The chlorite indicates that metamorphism has begun at this point. An index mineral is used in geology to determine the degree of metamorphism that a rock has endured. Dependent on the original make up of pressure and temperature that the parent rock (protolith) was subjected to, chemical reactions between existing minerals in the solid state will produce new minerals. As an index mineral is located in a metamorphosed rock formation, it indicates that the lowest/weakest pressure and temperature exposure to the protolith has been achieved in order for formation of that mineral.
METAGRAYWACKE ROCK:
Metagraywackes are quartzose chlorite or biotite schists that contain coarse to very fine granules of blue quartz. It is a variety of sandstone that is generally characterized by its dark color, hardness and angular grains of quartz, feldspar and small rock fragments or lithic fragments that is set in a compact, clay-fine matrix.
OUTCROP:
The outcrop of metagraywacke across the Parkway to the west has an unique color caused by the minerals chlorite and sericite within the rock formation. These minerals were formed when the rocks in this area underwent metamorphism.
RESOURCES:
A Geologic Adventure Along The Blue Ridge Parkway in North Carolina by Carter/Merschat/Wilson...2001
QUESTIONS TO ANSWER:
1. What is the predominant color present on this outcrop?
2. Are any other colors present? If so, what color/s do you observe?
3. How much of this outcrop do you believe has begun metamorphism, based on the amount of chlorite present, based on your observations?
4. What two factors contributed to chlorite being the only index mineral apprearing at this outcrop?
5. 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.
Congratulations to NeverSeenGene for being FTF 7-1-22
GINGIN'S MESSAGE:
G - Grand in appearance as we gaze in the distance
R - Regal mountains of different stature
E - Enriching us for having the opportunity to stand on your grounds
E - Entrusting each to our responsibilities to care and respect where we stand
N - Nourishing our spirits, our minds and our hearts with your whispering winds and swaying tree branches
M - Moments only we are here at this grand location to explore while we can
O - Our responsibilities are not just to the land but for our future generations to behold as we do now
U - Unexpected finds and sights....a wildflower, a falling leaf, a bird taking wing
N - Never losing sight of the fragility of our Earth and how we need to protect it
T - Taking time to breathe in the fresh air, fragrances and feeling the warmth of the sun
A - Always practicing Leave No Trace ethics and picking up anything not left by us that doesn't belong to discard
I - Inside yourself, peace filled with excitement of being here, away from your daily routines
N - Night will come soon and blanket the mountains with darkness and the twinkling of stars above.