Welcome to an Unusual Spot for a Geology Lesson Earthcache!
As this is an Earthcache, there is no physical container. Answer the quesitons below to log this cache!
The stone covering the staircase wall here is travertine, a special type of limestone that forms differently from typical sedimentary rocks. While standard limestone often comes from the slow compaction of marine fossils and sediments over millions of years, travertine forms much more quickly at the surface — especially around hot springs, caves, and mineral-rich waters.
Travertine is created when calcium carbonate precipitates out of water, leaving behind layers of stone. As gases (especially carbon dioxide) escape during the formation process, they leave behind tiny holes, pits, and voids, giving travertine its distinct porous texture.
These small cavities, combined with travertine’s lighter color tones (cream, white, tan, even rusty reds), make it a favorite in architecture. However, this texture also makes travertine more vulnerable to weathering, cracking, and colonization by living organisms — like lichen, which you will see at this site.
In addition to the porous texture, you will notice natural cracks and surface weathering. Some cracks form due to drying and shrinking during the stone’s creation, while others develop later from mechanical stress, slight building movement, or expansion and contraction from temperature changes.
This EarthCache highlights:
- The unique surface features of travertine
- Signs of natural and environmental changes after installation
- Biological interactions (such as lichen growth)
Educational Section
How is Travertine Different from Typical Limestone?
- Travertine forms by rapid precipitation of minerals from water, not by slow accumulation of marine fossils.
- It is often more porous, with many natural cavities.
- It usually forms near springs or cave mouths.
- Traditional limestone can contain more fossilized remains and tends to be denser and less holey unless exposed to heavy weathering.
Why Are There Cracks and Lichen Here?
- Cracks in stone structures can be from environmental stress (like building shifting, freeze-thaw cycles, or mechanical stress).
- Lichen are simple organisms that thrive on surfaces like stone. They are part algae and part fungus, living together symbiotically, and they secrete acids that slowly break down rock over time.
Did You Know?
Some famous ancient Roman structures, like the Colosseum, were built with travertine!
To receive credit for this EarthCache, please visit the site and answer the following questions. Use the provided marked photograph to help locate the features! The picture above will help you identify key points of interest that best illustrate this lesson.
LOGGING REQUIREMENTS
Please complete the tasks and questions below, and send me your answers. If logging for a group, please include the names of everyone in your group.
1) Red Circle: Observe the area marked by the red circle in the posted photo. What is unusual about this area? Describe its color, texture, and how it differs from the stone around it.
2) Blue Circle: Observe the area marked by the blue circle in the posted photo. What do you see unusual about this area? Describe its color, texture, and how it differs from the stone around it.
3) Surface Features: Look closely at the stone wall (not just in the circled areas). Describe the overall texture of the stone. Is the stone surface mostly smooth, rough, or full of holes? What do the holes and surface texture tell you about how this stone formed?
4) Take a photo of yourself (or personal item) at the wall. You can attach it to your found it log (optional).