Welcome to Killarney National Park! This earthcache will take you on one of the many scenic trails in the area and teach you a bit about the local geology. There is no physical container to find here; to log this earthcache, you will need to message or email us the answers to the questions below. In addition, provide a photo taken at the trailhead waypoint, with the stone "Arthur Young's Walk plaque and yourselves or a personal item visible.
There is 24 hour pedestrian access to Killarney National Park throughout the year. More information about the park is available at the park's official website.
It's All Arthur's Fault
The trail you are walking was blazed by English travel writer Arthur Young in 1776. As you walk in Arthur's footsteps, you are actually walking on a fault line. According to geologists, the Millstreet – Muckross Fault Line is a thrust fault, the result of the collision of two continents around 270 million years ago. The collision lifted the Old Red Sandstone beds, deposited during the Devonian period (around 345 to 395 million years ago), high above the younger limestone, deposited during the Carboniferous period (around 280 to 345 million years ago).
If you approach the cache from the trailhead near Muckross House, you will wind around several outcroppings of limestone. Here, there are clear signs that the rocks are undergoing biological weathering.
What is biological weathering?
Weathering can affect rocks in three main ways: through physical forces, chemical changes, or influences from living organisms. The latter is referred to as biological or organic weathering. Living organisms can impact rocks in various ways, which can make the rocks even more vulnerable to further physical or chemical weathering.
Plant roots
Cracks in rocks tend to trap soil as leaf litter and other organic matter break down into soil. Plant and tree roots often seek moisture and nutrients, penetrating these cracks. As the roots grow, they can exert pressure that widens the cracks. Additionally, some roots release acids that gradually dissolve the rock surface, providing essential nutrients to the plants.
Microbial activity
Microorganisms such as bacteria, mosses, lichens, and algae have adapted to extract nutrients from rocks by decomposing them with the help of organic acids. Lichens, in particular, play a significant role in rock weathering; they are not just one organism but a symbiotic group of fungi and algae. The fungi produce chemicals that break down the rock, while the algae feed on the minerals released during this process. The longer a rock is exposed to the environment, the more likely it is to host these organisms, which contribute to weathering. Their presence also fosters a moist chemical environment that speeds up the weathering process.
Animal activity
Animals contribute to the weathering of rocks as well. Some animals drill into rocks to create openings for shelter, while others burrow around them or expose surfaces to further physical or chemical weathering. Animals can also wear down stone surfaces by repeatedly traversing over them or breaking rocks, effectively weathering them down over time.
Logging this earthcache
To log this earthcache, email us or send us a message, and copy and paste these questions, along with your answers. Please do not post the answers in your log, even if encrypted. There's no need to wait for confirmation from us before you log, but we will email you back if you send a message or include your email address in the email. Group answers are fine; just let us know who was with you.
1. The name of this earthcache: Biological weathering at Muckross (Earthcache)
2. Describe the rock surface at the coordinates. What feature of the rock are the trees exploiting? In your opinion, are the trees merely filling the gaps or actively contributing to weathering the rock? Explain how you came to that conclusion.
3. Other than perhaps tree roots, name as many other potential causes of biological weathering you see at the coordinates. (We spotted at least four.) This would be living things that you can see with the naked eye, please. :)
4. Provide a photo taken at the trailhead waypoint, with the stone "Arthur Young's Walk" plaque and yourselves or a personal item visible. This can either be attached to your log or privately messaged or emailed to us.
The "personal item" for logging can be a GPSr, or a signature item like a personal geocoin, or even a piece of paper with your caching name. Be creative!
Please do not post any photos that reveal the details discussed in the logging questions.
Sources
Earth Eclipse - What is biological weathering?
University of Nebraska - Lincoln, Plant and Sil Sources eLibrary
Killarney National Park - Geology
Killarney National Park - Muckross and Dinis Trails
Millstreet Town - On Shaky Ground