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Before doing this Earthcache which is a 5km roundtrip or hike from the roadside parking area across rough and boggy ground and involving a small climb, you should wear decent boots and suitable clothes for wet and or cold conditions, the weather here is pretty changeable. Also no dogs are allowed because of sheep in the area and best advice is to leave gates as you find them.
A Glacier is formed as a result of more snow falling than can melt on an annual basis. They usually form on the shaded or colder side of a mountain. Over time this snow accumulates and is compressed into ice under it's own weight and by melting and freezing again and again. This compact snow becomes more and more dense and is called firn. Then due to gravity it begins to 'flow' down hill. As it does so it carries lots of debris from great big rocks to fine clay sized material.
A Moraine is any glacially formed accumulation of unconsolidated glacial debris (soil and rock) that occurs in currently glaciated and formerly glaciated regions on Earth
All the material being transported is eventually deposited elsewhere creating the features we see today. This material in the ice comes from more than one source, scree breaking off as a result of freeze/thaw from higher up the mountain falling onto the glacier and material that is primarily at the base of the glacier which is there as a result of having been 'Plucked' from the surface of the rock beneath the ice and also because of 'Abrasion'.
Plucking is literally the ice grabbing rock that has become detached due to the massive forces being exerted on it and again freeze/thaw working on cracks and fissures to dislodge and carry away chunks of material. This material is incorporated into the ice at the base of the glacier making it incredibly abrasive, which in turn causes it to remove even more material. All of this action over time gouges out the 'U' shaped valleys that are typically associated with glaciers and in particular the birthplace of a glacier, something called a Cirque or Corrie or in Irish Coum. This Earthcache is situated in one such place.
A corrie is described as semi circular hollow in the side of a mountain. It has a steep back wall and sides and the base could be described as bowl shaped, this is created by rotational slip due to the weight of ice travelling down and forward. Thousands of years of plucking and abrasion gouged this huge hole out of the mountain so that all we can see here today is the Cirque itself and different types of moraine and lots of great big rocks left in place after the ice melted.
Moraine Types
- Lateral moraine: these are ridges of debris that were deposited at the sides of the glacier along the length of the valley and consist of scree that tumbled on to the ice from higher up on the walls of the valley.
- Medial moraine: This type is formed when 2 Glaciers meet and their Lateral Moraines merge to form a single moraine.
- Recessional moraine: These are often seen as a series of lesser ridges running across a valley behind the terminal moraine and are formed during temporary halts in a glacier's retreat
- Terminal moraine: This is a ridge of unconsolidated debris deposited at the snout or end of the glacier and marks the maximum advance of the glacier
Aerial view of part of this Earthcache showing some of the features.
An idea of what this Glacier might have looked like back then
Logging Requirements
Important
- You will need a measuring tape or hiking pole to help with judging how high the moraine is and the size of the boulder.
- Have a look at the Waypoints on this page for more information on how to go about answering these questions before you get here.
QUESTIONS.
Please send the answers using the message center and not by email because I may miss them there.
- How high is the terminal moraine at reference point Q1?
- Tell me how high the biggest boulder at this reference point Q2?
- Here at reference point Q3 you can see the 'interior' of a lateral moraine, describe the material it is made of?
- Is the floor of this Cirque flat or bowl like in the general vicinity of reference point Q4?
