Welcome to an EarthCache!
Unlike traditional geocaches, there is no container to find and no logbook to sign. Instead, EarthCaches bring you to a location where you can learn about the unique geology of our planet. At this site, you’ll explore a monument built from fossil reef limestone and discover how its porous structure connects directly to Florida’s underground aquifer system. To claim credit, you’ll make observations and answer questions about what you see.
Logging Requirements
To claim credit for this EarthCache, please visit the coordinates and observe both boulders.
Answer the following questions and send your responses through the Message Center (do not post them in your public log).
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Texture and Layers
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Which rock (A or B) shows visible banding or layering?
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Briefly describe how its surface looks or feels (smooth, rough, grainy, etc.).
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Formation Forces
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Based on your observations, which rock likely formed under directed pressure (causing foliation) and which under uniform pressure or heat (non-foliated)?
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Explain your reasoning in a sentence or two.
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Identification
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Classify each rock as foliated or non-foliated metamorphic, and name a possible rock type for each (e.g., gneiss, schist, quartzite, granite).
Required Photo:
Take a picture of yourself, your GPS, or a personal item near the rocks to show your visit (please avoid close-up shots that reveal your answers).
Earth Science Lesson
North Carolina’s landscape was shaped by enormous geologic forces that date back more than 300 million years, when ancient continents collided to form the supercontinent Pangaea. The pressure and heat from those collisions transformed much of the state’s crust into what we now call metamorphic rock.
A metamorphic rock is any rock that has been changed from its original form—whether igneous or sedimentary—by intense heat, pressure, or chemical activity deep within the Earth. These forces can rearrange the rock’s minerals, flatten or stretch its structure, and even create new minerals altogether.
Two main factors influence how a metamorphic rock appears:
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Pressure Direction – When pressure acts more strongly from one direction than another, the minerals in the rock align in bands or layers, forming what geologists call foliation. These layers are visual evidence of stress deep within the Earth’s crust.
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Temperature and Chemical Change – When rocks are heated evenly or exposed to chemically active fluids, the minerals may recrystallize without layering, resulting in a more uniform and crystalline appearance.
Across North Carolina’s Piedmont and Blue Ridge regions, ancient mountain-building events created a variety of metamorphic rocks—each one recording a different balance of heat, pressure, and time.
At this site, two large boulders have been placed as part of the landscape. Though they may not be in their original geologic setting, they still serve as excellent examples of metamorphic textures that can be compared and observed firsthand. By studying them, visitors can see how the same geologic forces that shaped the state’s mountains also left their mark here in miniature form.
📚 References
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North Carolina Geological Survey (NCGS): Geology of the Piedmont Region
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U.S. Geological Survey (USGS): Metamorphic Rock Identification Guide
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National Park Service: Teaching with Metamorphic Rocks (nps.gov)
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North Carolina Department of Environmental Quality: Carolina Terrane and Metamorphic Provinces
AI Disclaimer: Parts of the text on this EarthCache page were edited with the assistance of AI tools (ChatGPT). AI was used to check scientific sources, ensure against plagiarism, and help craft a lesson that is unique and not duplicative of nearby EarthCaches. The cache owner created, verified, and is fully responsible for all content presented here.