DLA2015 Coastal Erosion.
What is Coastal Erosion?
(as defined by Wikipedia)
Coastal erosion is the wearing away of land and the removal of soil, small rocks and sediments by wave action, tidal currents
wave currents, drainage or high winds. Waves, generated by storms, wind, or fast moving motor craft, cause coastal erosion
which may take the form of long-term losses of sediment and rocks, or merely the temporary redistribution of coastal sediments;
erosion in one location may result in accretion nearby. The study of erosion and sediment redistribution is
called 'coastal morphodynamics'. It may be caused by hydraulic action, abrasion, impact and corrosion.
On non-rocky coasts, coastal erosion results in dramatic (or non-dramatic) rock formations in areas where
the coastline contains rock layers or fracture zones with varying resistance to erosion. Softer areas become eroded much faster than harder ones,
which typically result in landforms such as tunnels, bridges, columns, and pillars.
Also abrasion commonly happens in areas where there are strong winds, loose sand, and soft rocks.
The blowing of millions of sharp sand grains creates a sandblasting effect.
This effect helps to erode, smooth and polish rocks.
The definition of abrasion is grinding and wearing away of rock surfaces through the mechanical action of other rock or sand particles.
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When you reach the posted coordinates you will see that most of the erosion in this area has been caused by Waves, Snow and Ice Build up and
Heavy down pours of rain.
Another effect caused by the waves is the erosion and the creation and formation of Pebbles and/or Cobbles
A pebble is a class of rock with a particle size of 2 to 64 millimeters based on the Krumbein phi scale of sedimentology.
Pebbles are generally considered larger than granules (2 to 4 millimeters diameter)
and smaller than cobbles (64 to 256 millimeters diameter).
A rock made predominantly of pebbles is termed a conglomerate.
Pebble tools are among the earliest known man-made artifacts, dating from the Palaeolithic period of human history.
A beach composed chiefly of surface pebbles is commonly termed a shingle beach.
This type of beach has armoring characteristics with respect to wave erosion, as well as ecological niches that provide habitat for animals and plants.
There are many obvious signs of Coastal Erosion at GZ, from Exposed tree roots, pebble creation and smoothing, pot holes Etc.
To get credit for this Earth Cache, please send the answers to the following questions
to me via my Geocaching profile.
1) At the posted coordinates, find and describe one on the many shallow pot holes.
2) Name 1 other sign of Erosion here and describe it.
At location #3
3) How far from the posted coordinates does the Shingle beach start
4) How long is the Shingle beach?
5) Using the sizing listed above, are most of these Pebbles or Cobbles?
and finally at Location #2
Here you will find a Glacial Erratic (Big boulder)
6) Is there signs of the waves having an effect on this boulder?
Remember with all my Earth Caches, the idea is to learn a bit of Geological history and have fun
It IS NOT to cause you grief trying to give perfect scientific answers
Just do your best.
This Geocache is being hid for the DLA2015 MEGA Event GC5FPJB,
Do not seek until 9am on Saturday August 22nd, 2015