GRÁSTEINN OG ÁLFASTEINAR EARTHCACHE EarthCache
GRÁSTEINN OG ÁLFASTEINAR EARTHCACHE
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At the listing co-ordinates you should be looking at a huge boulder which appears to have caused the road to divert somewhat.
Large boulders such as this are usually glacial “erratics” – lumps of rock that fall onto the top surface of the ice, or are plucked up by the bottom of the glacier, and then carried, maybe hundreds of miles from their point of origin, by the slowly moving ice.
However, erratics can also arrive in other ways. For instance when the land is below sea level they could float past frozen onto an iceberg and then get deposited when the iceberg melts. Alternatively, they could be moved by an ice shelf – the terminal part of a glacier which is floating on the sea and not grinding away at the rocks below. Warmer water currents can cause the lower parts of such ice shelves to melt and drop the rocks and other materials that are being carried along. This last sort of deposition has recently been shown to have occurred between the islands off the tip of the Antarctic Peninsula and the Continent itself, making climatologists realise that the ice shelves which have so recently broken up due to 'global warming' have not always been permanent features in the past.
Back to this boulder in Iceland, however. This erratic is unusual in that it has a vertical line of marks running down it’s centre and is noteworthy enough to have an information panel nearby, explaining how this boulder got to its present position.
However the wording is all Icelandic so you may need to write down the relevant parts or take a picture for later translation. It seems this rock is known locally as the “Greystone” or “Elfstone” because the line of marks seems to indicate where these ‘creatures’ tried to split it apart! To log this Earthcache you'll have to do better than that, however!!
Use the information on site and e mail me to say:-
a) How you think the rock got here. Was it one of the the methods described above or some other?
b) Tell me how many ‘notches’ there are in a vertical line, starting from the clump of grass on top, including the 2 ‘notches’ which are filled with growing flowering plants.
& c) Provide a more likely scientific explanation for the marks than the “work” of imaginary creatures.
When You get the ‘go-ahead’ you can then log your ‘Find’, hopefully also uploading a picture of yourself at the site alongside the boulder, but this is now optional. Please be sure that any photo does NOT show the line of markings.
Additional Hints
(No hints available.)