Caledonia falls EarthCache
-
Difficulty:
-
-
Terrain:
-
Size: 
(other)
Please note Use of geocaching.com services is subject to the terms and conditions
in our disclaimer.
Troodos geology.
The Troodos mountain range is an ophiolite, a term used to describe a group of igneous rocks which make up the oceanic crust. Troodos is part of a very ancient section of oceanic crust which was uplifted to its present position due to the collision of the African and Eurasian Tectonic Plates and the subduction of the former beneath the latter. It is considered the most complete and best-studied ophiolite in the world.
Above the Sheeted Dyke Complex are the volcanic rocks of Troodos, consisting of pillow lavas and lava flows. The characteristic spherical to ellipsoidal pillow shapes are a result of water pressure during the submarine volcanic activity and their spreading, while the pillow lavas can be 30-70cm in diameter. The crust is glassy, due to the speed of cooling and the inside is honeycombed, because of the spaces formed by the sudden expression of gases contained in the incandescent lava (>1000° C).
Above the ophiolite rocks and the pillow lavas in particular, we find the first dark/brownish sediments, several metres thick and spreading horizontally for tens of metres, known as umbers. These sediments are rich in iron oxide and manganese and are similar to the iron-rich sediments found on the sides of the mid-ocean ridges in today’s oceans. Their creation is due to warm undersea fluids, rich in iron and manganese, that were laid down on the sea-bed.
Waterfalls
Waterfalls commonly form where water rushes down steep hillsides in upland areas. They are typical of the upper valley but can be found in the rivers lower courses where the process of rejuvenation creates enough potential energy for vertical erosion to recommence closer to the mouth of the river. The height and number of waterfalls along a stream or river depend upon the type of rocks that are being eroded by the water. This typically occurs in areas where alternating bands of bedrock, made up of varying levels of resistance, form the bedrock. Some types of rocks (shale, for example) wear away more easily than others (such as sandstone or limestone).
As the river or stream wears away the weak rocks, they travel across the surface of stronger rocks. These more resistant rocks become the capstones to waterfalls. The number and thickness of these stronger rock units in a vertical sequence of rocks control how many waterfalls there are and how much vertical drop there is on each waterfall.
A cross section of a typical waterfall
The diagram in the iamges for this cache shows the formation of a waterfall. Soft rock is undercut (1). This leaves a layer of hard rock which overhangs the layer of soft rock (2).
The water flows over the overhang and creates a plunge pool in the soft rock below. As the water hits the plunge pool it will erode it by both hydraulic action (the force of the water against the bedrock) and by abrasion (where the material carried by the river acts like sandpaper against the riverbed) (3). Eventually, the overhang will collapse due to the erosion of the soft rock beneath it. The waterfall then retreats upstream (4)
Your task:
1. After learning of Troodos geology look at the waterfall for any sign of umber. describe its location on the falls and what effect the water has had on it
2. At the top of the falls on the right side you can see a prominent shape cut in to the rock, what shape is it?
3. photos of your trip to the falls.
Please take care in the winter months with the additional rain and snow melt, the river could become dangerous. If so, do this cache a different day. I recommend late spring early summer.
Additional Hints
(No hints available.)
Treasures
You'll collect a digital Treasure from one of these collections when you find and log this geocache:
Loading Treasures