Franz Josef glacier flow film

This is amazing -- a time-lapse photography sequence showing how the ice of the Franz Josef Glacier in New Zealand flows over a period of 18 months.

bit.ly/1I7Fk20

Sea level 20,000 years ago

 I came across this very striking image which shows in red the area which is currently inundated but which was dry land at the peak of the Devensian glacial episode c 20,000 years ago.  In Britain, the North Sea, Scandinavia and the Baltic, large parts of this "dry" area were ice-covered, and because of the isostatic depression of the land surface under the weight of ice, the sea was actually able to penetrate across the boundary between the area shown in red and the area shown in light blue.  As ever, things in reality were a good deal more complex than they appear in nice simple illustrations like this one.......

Science in the open -- or behind closed doors?

I've been looking at my past posts, and discovered that there are 218 posts mentioning Rhosyfelin between 2011 and now.  That's a lot of posts -- and, thanks to my faithful community of readers and contributors, a lot of open and friendly discussion, with a vast range of topics relating to this site, put under the microscope.  You can do the search for yourselves, and check out what we have discussed........

It's interesting to explore which posts have been most popular, in terms of page views and comments.  One of the most popular was the recent post about BigFoot!  That says something in itself about the state of science in the world........

The Rhosyfelin Fracture Pattern  has 511 page views;
The Incorrigible Quarry Hunters turn up at Carn Goedog has 596 views; 
 Big meltwater conduits beneath an ice stream has over 3,000 page views;
The Carn Meini "Bluestone Quarry" -- Oh no it isn't! Oh yes it is! has 811 views;
The Stonehenge rock types -- time for an update? has 749 views;
The Rhyolitic "debitage" around Stonehenge has 1242 views; 

Rhosyfelin -- is it a quarry site? has 549 views;

Devensian Welsh Ice in North Pembrokeshire has 1400 views;

The Neolithic Quarry Obsession has 632 viws;
Bronze Age use of mauls and hammerstones has 1163 views;
Stonehenge -- a breeding ground for pseudoarchaeology? has 1264 views;

A Whin Sill erratic cluster in the Stevenage area? has 529 views;

STRAY STONES in South-West England has 1451 views;

The Craig Rhosyfelin dig has 1118 views;

An evening of fairy tales has 597 views;

More on the Rhosyfelin outcrops has 659 views;

How to manufacture a Neolithic quarry has 577 views;

and there are others which have had more than 400 page views.

All in all, there are 711,000 page views on the blog, from all over the world.  It's obvious that most of the views are from people interested in Stonehenge, but I suspect that there are a lot of views from geologists and geomorphologists as well, since my illustrations come up quite prominently when people search on Google for images.  I presume that Google researchers are often directed to the site -- although I am totally mystified about how tags and keywords work.  Sometimes I get messages from experts who say I should take "search engine optimisation" (SEO) more seriously, and that I should earn some dosh through allowing adverts on the site.  "No thank you" to both of those......

What I have tried to do on the blog is encourage "folk science" which invites an open exchange of information and an open testing of hypotheses, involving both specialists and those who just want to learn. 

Back to Rhosyfelin.  The other way of doing things is to obtain a large research grant, dig away on a site happily for several years, tolerate no dissent, publish nothing at all about the progress of the research, and invite no dicussion with people who might actually have something to contribute or some hard questions to ask.  The ruling hypothesis rules, and after a few celebrity PR lectures here and there to amiable and gullible audiences, to prepare the ground, everything is announced in a blaze of glory in conjunction with a big paper involving many members of the research team.  It may be good, and it may be rubbish.  We shall see.  If it's published in an archaeological journal, it's doubtful that any of the peer reviewers will have been earth scientists.

When said paper appears, accompanied no doubt by a TV spectacular (rumoured to be on Nat Geog Channel), let's hope that those responsible have read this blog and picked up some useful information from it about glacial and periglacial processes and about the events of the Ice Age.......

I'm not accusing Prof MPP and his colleagues of anything unusual here.  This "science behind closed doors" happens all the time, in many different fields.  There is huge competition for research grants, and reputations are at stake both for individuals and academic institutions.  Universities have their own publicity machines these days, and they employ professional publicists who write press releases about important  -- or unimportant -- research which are sent out to the global media.  Saturation coverage.  I have seen countless examples of crap research glorified in carefully crafted press releases which are then regurgitated almost unaltered in the press and on the telly.  Journalists these days don't investigate -- they regurgitate.  For the researchers, exposure is everything.

Now that commercial interests have become important, another factor comes in to play.  Research teams don't publicise their results too far ahead, even in their own peer groups, since they want to get things as right as possible before publishing and have a maximum impact.  But there is always SOME discussion with peers, for example through conference presentations or poster displays of key results.  So there are checks and balances, with the most radical ideas questioned and tested before they are submitted in the context of papers submitted to peer-reviewed journals.  But "commercial confidentiality" trumps all of that, and I have seen the insidious and dangerous effects of it in other fields.  Secrecy clauses come into play, and in medical science (for example) pharmaceutical commercial sponsors or biotech corporations reserve the right to vet research, insist on it being rewritten in a form which they approve of, or even veto publication altogether if the results are "inconvenient."  Very sinister indeed.  This is not the way science should be conducted, and I feel very strongly about it.  

So rumour has it that National Geographic has paid over rather a lot of money to the MPP research team with certain exclusive rights attached to the deal.  If that is true, shame on all concerned, since in that direction lies orthodox or establishment science, as once practiced in Stalinist Russia.........  Those who are obedient (and discover the things they are meant to find) are rewarded and flourish, while those who ask questions and come up with uncomfortable observations and results are packed off to the salt mines and are never heard of again.

There now.  That was a good gripe!  Feel better now.  Time for a cup of coffee and a chocolate biscuit.

Chatter marks and rock mechanics

Here are some more photos of the classic glacial erosional "micro features" on Rodloga Storskar in the Stockholm Archipelago.  Apart from the striae or striations which I have already described, these features are of interest in terms of rock mechanics, and they are all related to fractures on stressed rock surfaces.  We don't know how thick the ice was when these features were formed, but it might have been up to 2,000 m thick -- that means that the stresses on rock surfaces were enormous.


Nowadays these features are grouped together and are called "chatter marks", but as we can see from the photos below, there is a lot of variety in the forms.  The top photo shows a series of roughly parallel and regularly spaced linear fractures, approx perpendicular to the direction of ice movement:

 The next one shows many fractures in a small area, some of them crescentic gouges and others irregular and linear.  These were formed on a moulded surface across which the ice was rising so as to surmount a hill about 30m  high.  The theme of ice having its greatest effects on a rising land surface is a common one -- here there would have been compressive flow, as distinct from the extending flow accompanied by tension or dragging forces on the lee side of obstacles.

 Below we see a very large crescentic gouge -- almost 1 m wide, with many more smaller chatter marks in the vicinity.

 This rock face, again on a rising surface, has a high density of fractures of many different types.

And since large tools were required to create these gouges and fractures, here are a couple of photos of rocks seen littering the rock surface in the vicinity.  These are quite large enough to have been effectively pressed into the rock surface by the pressure of overlying ice.  The fractures are really brittle fractures -- and one contributing factor is the differential resistance of tool and bedrock.  It helps, of course, if the tool is harder than the bedrock, but tools under compression are more resistant to breakage than rock surfaces under tension -- so even if the tool rock type is the same as that of the bedrock, erosion and fracturing becomes possible.  But tools are of course also comminuted on the glacier bed.  The problem with all of this is that the actual processes involved are almost impossible to observe under present-day ice sheets.

  

The perfect crescentic gouge

I've seen a lot of crescentic gouges in my time, but this is probably the most perfect one I have ever encountered in the wild.  It's about 30 cm across, with the convex side facing up-glacier and the horns pointing down-glacier. It's got an almost perfect semi-circular or crescent shape, and looks like a new moon!  If you click to enlarge, you should be able see the slight colour difference between the smooth pink granite rock face affected by over-riding ice and the rougher texture left when part of the surface was crunched away by a large boulder forced downwards. 

This is just one of a series of photos taken on my recent visit to Rodloga Storskar in the Stockholm Archipelago.  More to come, with a discussion on rock mechanics......

A Long History of Rhosyfelin (3rd revision)

I have done some work on this document posted on SCRIBD.  Available for viewing online and download here:

https://www.scribd.com/doc/270896438/A-Long-History-of-Rhosyfelin-3

The revised version incorporates some of the recent observations at the site, but essentially I repeat that I have seen NOTHING to make me think this is a Neolithic quarry site.  The features described seem to me and my geomorphologist colleagues to be rather interesting from a Quaternary point of view, giving us additional information as to Anglian and Devensian events and helping us to understand what has happened here within the past 20,000 years or so.

One common comment from the experienced geomorphologists concerns the extent of the till and fluvio-glacial exposures, and the obvious traces of ice moulding and turbulent water flow across some of the rock surfaces on the col near the SW end of the dig site and also at the tip of the spur.  Surely the geologists and archaeologists whose learned paper we so eagerly await cannot have failed to notice these things??   Surely not.......? 

Please, somebody, put us put of our misery and convince us that even archaeologists and pet rock boys can recognise glacial deposits when they look at them and dig into them.

Genesis of a giant erratic

Scrambling about on the west side of Rødløga Storskar (in the Stockholm Archipelago) the other day I realised that the prominent rocky knoll I was climbing on, about 25m above the sea, was falling to bits. I have always recognized it as a well-developed roche moutonnee with a smoothed and moulded up-glacier side and a plucked and fractured lee side, facing south. The rocks here are Pre-Cambrian basement rocks, comprising pink and red granite and a wide range of metamorphosed igneous and sedimentary rocks which probably have some very complicated geological names.

The western flank of the roche moutonnee is breaking up, although many of the broken blocks on the cliffs are well smoothed by over-riding ice. So these blocks (some of them as big as caravans) have been entrained, moved and smoothed.  Most of them have not moved very far.

But then at the position shown in the satellite image above I realised that a deep crack about 30m long and at least 20m deep was the first sign of a massive shearing-off of rock on the south-western corner of the hillock.  In other words, the crack indicated the genesis of a giant erratic, since the block of granite to the south of it must have been bodily dragged away (by overriding ice) from a prominent fracture plane.  The gap is now in places up to 50 cms wide.  I calculate the size of the moved block to be about 40m x 30m x 30m -- which gives us a volume of c 36,000 cubic metres and a weight of around 100,000 tonnes.

That would have been rather a hefty erratic, had the Devensian Glaciation continued for longer.  It would have been moved southwards and no doubt broken up further, into lots of smaller erratics.  The large block is very heavily fractured and is petrologically varied too, so it could not have survived transport as a single super-erratic.  The photos below show the crack as it appears on the upper surface of this little promontory, and the broken or plucked southern face.  The bouldery beach is packed with erratics from near and far.

Men at work

One of my favourite Stonehenge photos!  From the EH Atkinson collection.  Wandering about like that on top of the lintels would never be allowed these days!  Does anybody know who the people are?

The ones they left behind.......

The Rhosyfelin "abandoned orthostat" is not alone......

On my recent day wandering about on Rodloga Storskar in the Stockholm Archipelago, I came across  quite a range of pseudo-proto-orthostats  -- here, there and everywhere, resting on rock platforms and almost all of them off the ground -- supported by pillars, props, wedges, fulcrums and even "railway tracks".  (These two large rocks, one weighing about 6 tonnes and the other about 5 tonnes, were obviously destined to be dolmen capstones, because there are many others in the lexicon that look very similar in shape.)   It's clear that all of the propped-up boulders in this area were destined for Neolithic monuments, and that they give us further evidence of the extent of Neolithic quarrying in this area.  They were clearly being dragged down towards the sea for loading onto rafts when they were abandoned.  Somehow or other they just got left behind.  Perhaps the builders of the nearest dolmens had already fulfilled their quota of capstones and supporting stones and free-standing monoliths?  Perhaps building priorities suddenly changed?  Perhaps sudden conflict disrupted a previously stable political alliance between tribes in different parts of Sweden?

Only joking.  These and thousands of other large boulders in this landscape of low islands and washed surfaces are glacial erratics -- still in the places where they were dumped, and still resting on the stones jammed beneath them when they were "let down" from glacial transport.  Most of the fine material (till and fluvioglacial sands and gravels) has been washed away as this area has gradually emerged from the sea as a result of isostatic uplift.  Wave action has played a great part in cleaning up the bedrock surfaces.  The total amount of isostatic uplift here is about 125m, and the land is still rising at a rate of 4mm per year.  During the Neolithic this area was still deeply submerged beneath the sea.