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Monday, 6 December 2010

The Irish Sea Glacier 450,000 years ago

Click on the map for easier reading

This is my model of the Irish sea Glacier as it might have looked at the peak of the Anglian Glaciation, about 450,000 years ago. I think that the evidence points to a very extensive ice cover, with a calving glacier snout in the South-west approaches, and with thin ice caps over Dartmoor and Exmoor effectively incorporated into the ice of the Irish Sea Glacier as it pressed inland across the north coasts of Cornwall, Devon and Somerset.  I propose that the glacier front reached at least as far east as the chalk escarpment in Wiltshire -- and maybe transgressed onto Salisbury Plain.

Since there was substantial isostatic depression in both the Bristol Channel and the English Channel, I propose that these were both flooded by the sea, and that the position of the coast was very close to that of the present day.  This made it possible for ice floes and icebergs to transport far-travelled erratic material eastwards, where it was dumped for the most part in deep water but occasionally on the wave-cut platforms where "giant erratics" can still be seen today.

See this post too:
http://brian-mountainman.blogspot.com/2010/06/sea-ice-and-giant-erratics.html
on Sea Ice and Giant Erratics -- June 2010

7 comments:

Anonymous said...

Neat and potentially important. I like the ice-bergs/dropstones in the English Channel.
Many of your 'problems' are answered.
How much is you and how much independantly agreed?
GCU In two minds.

BRIAN JOHN said...

Yes, I bet the English Channel is littered with erratics and morainic debris. This also fits well with Geoff Kellaway's idea (which I have explored in earlier posts) that north of the Mendips there was an ice stream incorporating eastern Welsh and maybe Midlands erratics; that the material from West Wales was brought in on an ice stream into the depression now occupied by the Somerset Level; and that the ice which flowed all the way down to the Scillies probably never had any contact with West Wales. So that ice (calving icebergs out into the Celtic Sea) may well have contained Scottish, N Ireland, Isle of Man, Cumbrian, N Wales materials -- quite a different assemblage. That is the material that might have ended up on the beaches of the Channel coasts. And the giant erratics DO look different -- I haven't yet come across any records of spotted dolerites etc in that collection.

This theory is so new that even I didn't know about it two days ago!! But the evidence does seem to fit -- I've been doing a lot of reading on the sea-level literature, and it makes sense. What I now need to do is invite comments from the guys currently working in this field.....

Kosta Dean said...

Brian,

The 'iceberg flotilla' may explain the errants along the sea coast. But how do you explain the 'empty pits' along the same coast? Why do you not mention these?

You again blocked more of my responses! Though I acknowledge your rights to this blog, you nonetheless do not have rights to Truth so that you can selectively pick and chose what you allow to be considered by your readers.

Your blocking my comments in your blog is no different than the 'blocking' of your 'glacier transport' theory by 'eminent' archeologists. Their 'rational' doing so is no different than yours.

I guess now this post will be blocked too!

Constantinos Ragazas

BRIAN JOHN said...

I have mentioned the empty pits in a previous post -- their origin is a bit problematical, but if they really are associated with an ice foot, then that is entirely consistent with what I am proposing.

Yes, Kostas -- I have blocked a couple more of your messages, as I have with other people's messages. My blog, and my privilege! I do not have any more right than the next person to determine what the truth may be -- but it's my blog, and as I say in my blurb I reserve the right to block off submissions that seem to me to be devoted to the promotion of wildly eccentric theories that I would classify as "pseudo science" or as attempts by practical jokers who are simply trying to wind me up. (Yes, there are some of those, too!)

Your theory, like that of James, seems to me to be gloriously unencumbered by actual evidence drawn either from Salisbury Plain or from areas where your proposed processes are operating and can be observed today. So I will allow intelligent debate, but I will not allow you a platform for your ideas until you come up with something that looks like evidence. The eminent archaeologists, whatever their shortcomings may be, do at least have some respect for the normal processes of evidence-based debate! If you want a platform, you can very easily set up your own blog site -- it's a very simple thing to do........

Kosta Dean said...

Brian,

If I did not respond to your post above, I will be leaving the impression that I have no response. But if I do respond and provide all the evidence, then you will accuse me of using your blog as a platform “ … to the promotion of wildly eccentric theories”. I have no book I seek to promote, Brian. Just the truth about Stonehenge! It's a catch 22.

I would love nothing better than to have an open debate with you about the merits of my theory. I refer the interested reader to my paper, “The un-Henging of Stonehenge”. A simple google search will link to it. They could judge for themselves if what I argue is some “wildly eccentric theory” or not.

I do take affront to your suggestion that I am putting forth some crazy theory undeserving of consideration! Not to leave the impression with some that this has not been thought out deeply and seriously by me, I include below a brief abstract. You could of course choose to block it, denying your readers the opportunity to form their own opinion of this.

My theory hypothesis a 'local ice' cover of Salisbury Plain at the time of the making of Stonehenge. No specific claim as to when that may have occurred. Such 'local ice' could have been formed by bodies of water (whether lake, sea or river) during long and sustained periods of freezing temperatures as is known to have been the case around 10,000 BC. The periglacial stripes excavated at The Avenue is evidence of that.

The 'local ice' would not leave behind the same trails and signs as an advancing and retreating glacier ice. Such lack of evidence for glacier ice at Salisbury Plain has been used to discredit your 'glacier transport theory' but has no relevance in my theory.

The lack of errants and trails of smaller stones at Salisbury Plain has also been used to discredit your theory. But such lack of evidence can easily be explained by my theory since the land would have been under the cover of ice and such stone litter would have just washed over the surface of the ice and not left behind to be found in the land.

I could go on listing in great detail how every single feature of the ground morphology around Stonehenge and other places can be explained through my theory. But I'd be luck if you would allow even this much into your blog!

As for James's theory, I don't believe I know it. Did you mean Robert?

Constantinos Ragazas

BRIAN JOHN said...

Hi Kostas.

My goodness, I am a very tolerant fellow! Let me repeat -- I think that your theory (and various others) are indeed wildly eccentric. We have had a thoroughly good and extended debate about your theory on this blog, and I have explained over and again that you cannot expect anybody to take your theory seriously until you can show analogies or parallels for the processes you invoke.

Ice does not simply build up on surfaces in the manner you suggest. Permafrost is frozen ground. Snowpatches may accumulate if precipitation exceeds melting, and they are entirely dependent upon snowfall over prolonged periods of time if they are ever to become snowfields and glaciers. They all obey the same rules today as they did in earlier glacial episodes. The physics of ice has not changed over time. If there are periglacial stripes on Salisbury plain, they show that there was an essentially bare ground surface -- they do not argue for an extensive "ice cover." You do not get long sloping surfaces of ice anywhere, across which conveniently elongated erratic columns can conveniently slide from A to B, and plop over a vertical ice edge to become implanted in the ground.

You say: "I could go on listing in great detail how every single feature of the ground morphology around Stonehenge and other places can be explained through my theory". With all due respect, you could go on enumerating your details, but I doubt that any serious scientist would count any of them as being valid evidence.

If you are arguing for a process, it has to be sensible in terms of the laws of physics, and it has to be supported by comparison and analogy. That is how science works. Your theory depends upon fantastical processes that have no modern parallels -- and therefore I will continue to treat them as wildly eccentric. I have exactly the same attitude to Robert's theory of deep submergence (with apologies to him for referring to him as "James") since he sees moats, harbours and shorelines everywhere where others see nothing of the sort; and where he brings no independent evidence to bear in support of his ideas.

Please put your explanations on your own web site or blog, Kostas. No more here, if you please!

BRIAN JOHN said...

Hi Kostas.

My goodness, I am a very tolerant fellow! Let me repeat -- I think that your theory (and various others) are indeed wildly eccentric. We have had a thoroughly good and extended debate about your theory on this blog, and I have explained over and again that you cannot expect anybody to take your theory seriously until you can show analogies or parallels for the processes you invoke.

Ice does not simply build up on surfaces in the manner you suggest. Permafrost is frozen ground. Snowpatches may accumulate if precipitation exceeds melting, and they are entirely dependent upon snowfall over prolonged periods of time if they are ever to become snowfields and glaciers. They all obey the same rules today as they did in earlier glacial episodes. The physics of ice has not changed over time. If there are periglacial stripes on Salisbury plain, they show that there was an essentially bare ground surface -- they do not argue for an extensive "ice cover." You do not get long sloping surfaces of ice anywhere, across which conveniently elongated erratic columns can conveniently slide from A to B, and plop over a vertical ice edge to become implanted in the ground.

You say: "I could go on listing in great detail how every single feature of the ground morphology around Stonehenge and other places can be explained through my theory". With all due respect, you could go on enumerating your details, but I doubt that any serious scientist would count any of them as being valid evidence.

If you are arguing for a process, it has to be sensible in terms of the laws of physics, and it has to be supported by comparison and analogy. That is how science works. Your theory depends upon fantastical processes that have no modern parallels -- and therefore I will continue to treat them as wildly eccentric. I have exactly the same attitude to Robert's theory of deep submergence (with apologies to him for referring to him as "James") since he sees moats, harbours and shorelines everywhere where others see nothing of the sort; and where he brings no independent evidence to bear in support of his ideas.

Please put your explanations on your own web site or blog, Kostas. No more here, if you please!