spacemouses's picture

Mystery holes

Observed: 26th May 2011 By: spacemouses
BLACKhole
Description:

Total mystery! These come in small groups around the Western Isles,along shore line. They also seen in Shetlands. 25-30mm in diameter. Depth varies. Side walls fairly smooth. Bottom roughish with a slightly deeper groove at 'outer' edge (Pic on right has sand in it and gives idea of what I mean). They could be man made, but none of the older generation that I have spoken too, know anything about them. Any chance they are made by a marine 'animal' of some sort?

Identifications

No identification made yet.

Species interactions

No interactions present.

Comments

John Bratton's picture

They look like the holes

They look like the holes geologists leave when taking a specimen. They may be legal, but there is a problem with illegal damage to geological SSSIs from this sort of thing. Were they in a particularly interesting outcrop?

spacemouses's picture

mystery holes

They have been there more than 20 years that I know of, so not in SSSI when/if drilled! No one can remember any drilling.I wouldn't think the rock along there is anything special.

anonymous spotter's picture

The symmetry -

is so accurate that man-made seems very likely. I'd say drilled, because any impact would probably produce a less-regular hole.

spacemouses's picture

Too accurate to be anything

Too accurate to be anything but manmade. Core samples would fit descriptions very well. Talking to man this morning who noticed them when he was a child, and he has lived in village 50 years. He has never heard who , when or why!

hfraser02026's picture

The scottish islands are

The scottish islands are renowned for their ancient geology, particularly lewisian gneiss etc. so I would say that this is the most likely explanation. When I studied geology at university we took field trips to the Western Isles. You might find this interesting :
http://www.scottishgeology.com/geology/geology_of_scotland_map/scotland....

DavidNotton's picture

Piddock

There are marine bivalve molluscs which can drill holes in rocks. E.g. http://www.glaucus.org.uk/Piddock.htm. It should be possible to distingusih piddocks and drill holes:

Piddock holes may be not quite round, and not the same diameter all the way along, and have a rounded bottom. They will be on parts of the beach where they can be covered by the sea each day. Different piddock holes will have different diameters as they grow.

Drill holes would be perfectly cylindrical with a groove round the edge at the bottom of the hole. Related drill holes will have the same diameter. They may be found by the sea and elsewhere too.

Drill holes may be an indication not of geological sampling, but of blasting to remove large rocks in incovnenient places or quarries. In these cases you will only see the bottom part of the hole, the rest and the surrounding rock having been blasted away. This technique has been used for 100's of years.

The first of the holes featured above might have been made by a piddock as it does not look perfectly round. The second is definitely a drill hole.

spacemouses's picture

There are about 6 holes in

There are about 6 holes in this group. The others are covered by sand. Shadow may be making the one hole not look round. They are all the same size. The cliffs here are quite crumbly. If you wanted to break them up, you would not need to blast.

Dioctria's picture

Drill Holes

I agree that these are drill holes.

Was there any arrangement to them? Either with relation to each other, or to the rocks themselves (e.g. from different strata)?

David

Refugee's picture

Mining samples

They may have been looking for uranium during WW2 secretly so no record.

Refugee

spacemouses's picture

Will answer those last two

Will answer those last two comments together. No pattern on Ness beach area. Two groups of a few holes. Can't remember about the ones I have seen elsewhere on Island. Mostly they are covered by sand this time of year. Come winter when sand washes away, they will be more visible. This is not the part of the world where anything can be done in secret! To drill half a dozen holes- entire population of island would have known before 1st one was finished! No one remembers. They will have been done a long time ago. Must be records somewhere. I (and a few others) just curious.

Refugee's picture

WW2 history

I think this would have to be followed up. I think some work was done on this. The material was difficult to transport due to enemy submarines being present.

Refugee

Refugee's picture

The bedrock

You can do a bit of DIY on this one. You need to take a cheep radiation monitor for a hike. The places to look are most likely to be north of the tectonic line that runs between Inverness and the Isle of Mull (still causing tiny tsunamis that lead to many myths about giant serpents).
The holes would have been made during some kind of military activity at a time of year when the sand was high and they would have waited for high tide in order to allow the sand to be smoothed again before allowing the public to get access again.

Refugee