Stockholm Archipelago -- striae everywhere

On the Precambrian basement rocks of the Stockholm Archipelago striae are ubiquitous.  They are almost everywhere, and on the islands they are of course best observed round the coastlines of the islands where vegetation is sparse.  Most of them in the area I'm familiar with are running directly N-S.   It's assumed that most are of Weicheslian (last glaciation) age, but some might be older, dating from a time when the ice flowing across this area was around 2500m thick.  Even during the Weichselian the ice was probably 2000m thick, and that translates into enormous basal ice pressures capable of using tools to scour, scratch and gouge the rock in spectacular fashion.

As I have said before (probably every summer at around this time!) the archipelago is a sort of glacial erosion laboratory.  A text-book's worth of stuff in every square kilometre.........

Most of the grooves are less than 2 cms deep, but now and then one finds deeper grooves or channels which can be more than 10 cms deep.  On any particular rock face one might find deviations from the "normal" orientation by up to 30 degrees, and because the ice has obviously moulded itself to the bedrock topography and has flowed around obstacles, on some sloping or vertical rock faces striae may run as much as 45 degrees away from the norm.  To work out the overall direction of ice movement it is always best to examine more or less horizontal rock surfaces.

Not all rock types carry striae, even here in the Stockholm Archipelago -- some that are very coarse-grained seem to resist polishing and scratching very successfully!

Sorted stone circles

A fabulous photo taken on Nordaustlandet, Svalbard, by Jenny Ross.  It shows sorted stone circles in an area of permafrost.  The sorting takes place in the active layer under the control of rather mysterious processes, which have been argued about by geomorphologists for many years.

It's much more common to see pictures of sorted polygons.  When the density of circles is too great for them to remain as individual entities, they press together -- and the result is that all of them assume polygonal shapes.

New image of the Ramsey Sound trench

Back in 2012 I posted a piece about those amazing 3D images of the Ramsey Sound trench:

http://brian-mountainman.blogspot.co.uk/2012/04/glacial-landforms-ramsey-island.html

So today it was a pleasant surprise to receive an even better image from Dr Paul Evans of Cardiff University.  Paul can be reached here:  EvansPS3@cardiff.ac.uk

He has kindly offered to make the data files for this new high-res image available to anybody who may be interested.

Here is the new image:

The trench is a real puzzle -- it is most unusual to find a trench or canyon of this type which is closed at both ends.  The excavation of the trench cannot be laid simply at the door of tidal scour.  And glacial erosion in this situation is not all that likely either, given that the prevailing direction of ice movement in both the Anglian and Devensian glaciations is most likely to have been perpendicular to the alignment of the trench, and not parallel with it.  So there must be some structural influences at play.  An interesting geomorphological enigma.

Tim's Jolly Jape

 

 The blue line shows the "axis" of the monument, and the red one shows the "newly discovered alignment."

Stonehenge mystery solved at last........ etc etc.  I've been watching with increasing incredulity the wonderfully gullible coverage in the media of Tim Daw's latest theory about the alignment of the flat face of stone 56 at Stonehenge.  There was even a photo on the BBC web site showing the sunset moment in just the right place, depending on where you stood to take the photo..... but let that pass.  This should of course have been published on April 1st, but somehow they got the dates mixed up at WANHS magazine.  So here we are, with yet another wacky alignment theory, by far the most implausible in a long history of such things.  And people keep on taking them seriously, obsessed with the search for meaning and significance. Almost anything will do, and the media will take it seriously.  So good for you, Tim! 

Er, you can't possibly be serious, can you....??

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Stonehenge's tallest stone 'points at winter sunrise'

http://www.bbc.com/news/uk-england-wiltshire-32356993

The tallest stone at Stonehenge points towards the sunrise on the midwinter solstice, according to a new theory from a steward at the site.
Historians have long known the circle of stones is aligned with the midsummer sunrise but Tim Daw says the tallest one is lined up with the midwinter sun.
It was previously thought the stone had been put back at the wrong angle when it was re-erected in 1901.
But Mr Daw, who works there, says his research shows its angle is deliberate.
Mr Daw said: "The largest stone at Stonehenge is not where it 'should' be, it is twisted.
"This stone, Stone 56, is the tallest one at the end of the inner horseshoe of sarsen stones.
"Because it was put back to the vertical in 1901 it has been assumed that the twist is the result of the modern excavators botching the job.
"My research shows that not only was the standing stone out of symmetry with the central solstice alignment originally, but that its now fallen partner had also been, and so were surrounding stones, including the Altar Stone."
Mr Daw, who last year came up with evidence that the outer stone circle at Stonehenge was once complete, said his newly discovered alignment was at 80 degrees to the line of the axis of the monument, which points to midsummer solstice sunrise and midwinter sunset.
"The stones point to the midwinter solstice sunrise and midsummer sunset," he said.
"This alignment had been missed by previous investigators... as they used an idealised plan rather than an actual plan for their calculations."
"This isn't some nebulous sighting line on a distant star; this is 100 tonnes of stone deliberately pointing to the major event at the other end of the day the rest of the monument celebrates.
"One stone out of line might be a coincidence but that it is five of the major stones, at least, shows it was a designed feature.
"It shows what can be discovered by simple observation even in such a well-researched site as Stonehenge."
Director of the Wiltshire Archaeological and Natural History Society (WANHS), David Dawson, said: "This is an interesting new idea which highlights the "skew" of the Stonehenge trilithons, which has been known for some time.
"It highlights the significance of the summer and winter solstices at Stonehenge, and the 80 degree angle between them.
"We know that the Bush Barrow lozenge, on display at the Wiltshire Museum, hints at this same significant astronomical feature.
"There will now be a debate between archaeologists and a re-examination of the evidence to test this new hypothesis."
Jessica Trethowan from English Heritage said it was "an interesting idea".
Mr Daw's theory has been published in the latest WANHS magazine.
People traditionally gather at Stonehenge for the winter and summer solstices

Very naughty

 

It's amazing how some people just love making mischief.  The top photo is from this year's Summer Solstice gathering at Stonehenge and yesterday the lower photo started doing the rounds on social media, with masses of complaints about yobs, middle class tourists and upper class twits just turning up for a bit of partying, leaving filth everywhere for the nice kind druids to tidy up.........  people were invited to express their outrage, which of course they did, in droves.

But here is the strange thing.  Somebody noticed that the photo was actually one that appeared in the papers in 2009, and that it has nothing whatsoever to do with this year's celebrations, which were apparently very orderly and jovial.

What on earth is the point of this trouble making?  Strange world we live in.....

Strange sighting at Rhosyfelin

Our roving reporter Phil Morgan has sent this photo for our edification.  Click to enlarge.

Phil recounts that he was wandering in the Brynberian area (in 2012?), looking for traces of quarries and such like, as one does, when he noticed something strange, at the far end of the crags.  He grabbed his camera and quickly took one photo.   He could hardly believe his eyes -- for there was the mythical creature referred to by the locals as Roger of Rhosyfelin.  The creature had not been seen for many years, and it is thought that this is the first time for it to be caught on film.  It is quite unrelated to the local Afanc (which is a water creature) and looks more like Bigfoot than a fairy or a goblin.

According to legend, it is quite harmless, and shuns the limelight, but it has a tendency to remove lots of trees in a frenzy of activity, creating smallish quarries for reasons that are as yet unclear.  As we can see from the photograph, it was in the middle of its task when Phil came along with his camera.  It ran off up the valley, wailing balefully, and leaving a considerable mess behind.  No doubt it has subsequently been hard at work elsewhere in the woods, making other quarries.

It is understood that Roger's work puts the National Park Authority in something of a quandry, since the quarry has been excavated without planning permission.

Modern people in fancy dress

This is a rather charming Danish cartoon which I used in my book on Scandinavia more than 30 years ago.  It's a gentle dig at the manner in which the comfortable, placid Danes like to remember their past and imagine themselves as heroic and seriously nasty Vikings.  I also recall that when I started to write historical fiction, the most significant piece of advice I received was this:  "Rule Number One for historical fiction writers:  take great care that in defining your characters you do not create modern people in fancy dress."

I guess the same advice might be applied with advantage to archaeology,  which is full of people who talk about Ancient Wisdom and who imagine their ancestors of more than 5,000 years ago as having extraordinarily sophisticated belief systems and social structures, not to mention high technical ability including the ability to undertake long-distance navigation in complex terrain and the ability to transport very large stones over great distances.

Hunting and gathering

In case any of my fellow bloggers wonder why I haven't been to Rhosyfelin lately, it's because I am doing some experimental archaeology in the Stockholm Archipelago, working out how our hunting and gathering Neolithic ancestors survived...... been moving some big stones too, which were causing problems for my prehistoric lawn-mower.

A Rhosyfelin glacial erratic

This is one of the glacial erratics collected from the till at Rhosyfelin.  It's a mudstone pebble about 10 cms long --  probably derived from the Ordovician mudstones and shales which are common along the North Pembrokeshire coastal strip -- and which are also found among the volcanic rocks of the Fishguard Volcanic Series.  This pebble has got a number of smoothed glacial facets on it, with a fresher breakage on the right-hand corner and some nice striations running in various directions.

I'm still not at all sure that the archaeologists (or the geologists working with them) recognize the presence of till and fluvio-glacial deposits at this site -- although I am quite mystified as to what else these very prominent deposits might be called.  In the talks by Prof MPP and colleagues the pre-Holocene sediments have been notable for not being mentioned at all.......