NOTE: Limestone Pavement is a protected under the EU Habitats Directive. Please do not remove, rearrange, or damage this important natural feature.
Large rocks, such as the limestone boulder near Poulnabrone portal tomb, were transported by ice sheets during the last Ice Age and deposited when the ice melted. Granite and sandstone erratics from Connemara and south Co. Galway are also found in the Burren.
Clints and Grikes
The crevasses in the limestone pavement are called grikes which from between blocks of limestone called clints. Grikes are just one of the many types of karst feature that forms when rainwater dissolves limestone.
Small hollows (kamenitza) form on limestone surfaces by rainwater dissolution. Rainwater is slightly acidic ( ~ pH 6), and it dissolves limestone. Solution channels called rillenkaren form where water flows off the sides of the limestone pavement.
Dolines are many large hollows and depressions in the limestone landscape near Poulnabrone Portal Tomb. These large hollows are called dolines. Dolines form when a cave roof collapses into the underlying cave, or when limestone bedrock is dissolved away to create a large hollow.
TO LOG THIS EARTHCACHE
please send me an e-mail through my profile with the answers of the following questions:
1. Look for the large rock near the Dolmen and estimate its dimensions!
2. Which words are missing in the picture of "Clints and Grikes" above?
3. Take a look at the Kamenitzas and describe their form!
4. Are there any Dolines in the area of the dolmen? Where?
If you look at the information boards around the dolmen you will be able to answer the questions, especially question 2 and 4
You're allowed to log directly after sending me the mail, if there are problems with the answers, I'll contact you!
OPTIONAL: Look for a deep Grike and try to stand in it and take a picture
Here is an example how your picture could look like: