NOTE:
This is an EARTHCACHE!
There is NO PHYSICAL CONTAINER, and to log a find you need to email the answers to the questions below to me, by clicking on 'heartradio' just below the cache title and then clicking 'Send Email'.
If after 24 hours of you logging your find I still haven't received your answers, your log risks being deleted.
TARR STEPS
TARR STEPS INFORMATION
The Tarr Steps are a clapper bridge across the River Barle in the Exmoor National Park, Somerset, England. They are located in a national nature reserve about 2.5 miles (4 km) south east of Withypool and 4 miles (6 km) North West of Dulverton. A typical clapper bridge construction, the bridge possibly dates to around 1000 BC. The stone slabs weigh up to 1-2 tons apiece. According to local legend, they were placed by the devil to win a bet. Half of the bridge was washed away by the river whilst heavily swollen by rain in December 2012. The bridge has now been re-assembled.
********************************************************
LOGGING TASKS
TO LOG THIS CACHE, EMAIL THE ANSWERS TO THE FOLLOWING QUESTIONS:
1) Looking at the descriptions of the rock types below, have a look at the FLAT STONE SLABS on the bridge and see if you can identify the rock type. Explain why you think it is that type.
2) Using your GPS, measure your height above sea level at GZ.
3) Measure the length of the bridge. Your GPS's waypoint function may prove useful.
OPTIONAL TASK: Take a photo of yourself/your GPS (please do not show height above sea level on it) with the bridge in the background. PLEASE DO NOT POST CLOSE UP PICTURES OF THE BRIDGE AS IT COULD GIVE AWAY THE ANSWERS
IMPORTANT: Please email answers when you log the cache. Unless you particularly want your log deleted do not put them in your online log. You don't have to wait for permission to log.
********************************************************
ROCK TYPES TO CHOOSE FROM
TYPE 1: LIMESTONE
Limestone is a fine to medium-grained sedimentary rock. It is usually grey, white, yellowish or tan. It can often be streaked red with iron or black with magnesium impurities. Limestone is made up of the mineral calcite. It does not contain any visible crystals but it can sometimes look sugary. Limestone typically containsfossil shells and corals which are themselves made up of calcite.Limestone can be formed by the burial of coral reefs, but mostly it forms from lime rich mud in warm tropical waters.
TYPE 2: GRITSTONE
Gritstone or grit is a hard, coarse-grained, siliceous sandstone. This term is especially applied to such sandstones that are quarried for building material. British gritstone was used for millstones to mill flour, to grind wood into pulp for paper and for grindstones to sharpen blades. "Grit" is often applied to sandstones composed of angular sand grains. It may commonly contain small pebbles. It is grey in colour and often used for building due to its hardness.
TYPE 3: SANDSTONE
Sandstone (sometimes known as arenite) is a clastic sedimentary rock composed mainly of sand-sized minerals or rock grains. Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any color, but the most common colors are tan, brown, yellow, red, pink, white and black. Since sandstone beds often form highly visible cliffs and other topographic features, certain colors of sandstone have been strongly identified with certain regions.
Rock types information from http://www.wikipedia.org/ and http://www.open.edu/
********************************************************
If you are really struggling with the first question, please let me know.
| I have earned GSA's highest level: |
 |
