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?
There are three types of weathering that can affect rocks. They can be physically affected by forces, they can undergo chemical changes, or they can be affected by living organisms. This last category is called biological or organic weathering. Living organisms can affect rocks in several different ways; this can in turn leave the rock more susceptible to additional physical or chemical weathering.
Plant roots
It's common for cracks in the rock to accumulate soil as leaf litter and other detritus accumulates and degrades into soil. Plant and tree roots penetrate the cracks seeking moisture and nutrients. As the roots grow, they can physically force the rock apart, widening the crack. Some plant roots also produce acids that can eat away at the rock surface, again providing nutrients to the plants.
Microbial activity
Bacteria, mosses, lichens, and algae have evolved to draw nutrients from rocks by breaking them down using organic acids. Lichen in particular can contribute to rock weathering; this is not a single organism, but actually a symbiotic colony of fungi, which secrete the chemicals that break down the rock, and algae, which subsist on the minerals producted by the weathering. The longer a rock has been exposed to the elements, the more likely it is that these organisms have attached themselves to the rock and worked to weather it. Their presence also creates a moist chemical climate that can accelerate weathering.
Animal activity
Animals can weather away rock as well. Some animals actually drill into rocks, boring holes in them to seek protection. Others may just burrow around rocks, digging up rocks or otherwise exposing rock surfaces to further physical or chemical weathering. Animals can also wear paths in stone by continually traveling over them, breaking rocks, and so on.
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