THE BOOK
Some of the ideas discussed in this blog are published in my book called "The Bluestone Enigma" -- available by post and through good bookshops everywhere. Bad bookshops might not have it....
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Saturday, 17 January 2015

Glaciation of Dartmoor -- new book


This new book, edited by David Evans and Stephan Harrison, has recently been published by GWLG and QRA -- £18 to non-members.  It's very nicely produced and is easy to read -- and has been intended for use as a field guide.

The basic findings have been reported on this blog already, following the publication of a 2012 paper:
http://brian-mountainman.blogspot.co.uk/search?q=+dartmoor+glaciation

In the first part of the book there are chapters on landscape evolution, peroglacial features, glacial geomorphology and the numerical modelling of the Dartmoor ice cap.

The second part of the book is mostly about key sites which can be visited, book in hand.

It's very useful indeed, and emphasises that Dartmoor must have been glaciated more than once.  The authors also tie in the field observations with the numerical modelling done by Alun Hubbard and others.  The basis theme is that during the Devensian -- and by implication during the Anglian as well -- there must have been several small cold-based glaciers and ice caps beyond the edge of the Irish Sea Glacier as it waxed and waned.

27 comments:

Constantinos Ragazas said...

Brian, quoting from your post …

”The basis theme is that during the Devensian -- and by implication during the Anglian as well -- there must have been several small cold-based glaciers and ice caps beyond the edge of the Irish Sea Glacier as it waxed and waned.”

This would seem to indicate Salisbury Plain and the Somerset Flats would be similarly impacted by the same freezing conditions. And if there were ”formed a pro-glacial lake in lowland Somerset” (see your post on “Glaciation confusion on North Somerset”), it would likely be frozen during these freezing times.

One thought that should keep you up at night! If glaciers transported the bluestones from Wales to Salisbury Plain, how did these long pillar stones stay intact during the stressful glacier advance you hypothesize?

Kostas

BRIAN JOHN said...

Kostas -- the only place where pro-glacial lakes are more or less permanently frozen are the Antarctic Dry Valleys. In the mid-latitudes, no matter how severe the climate, there would have been summer melting.

as for pillar stones, see previous posts.

Constantinos Ragazas said...

Brian,

Perhaps! And more likely if the surface of the glacier lake freezes but the bottom stays wet. But if the entire lake solidly freezes, unlikely it would all melt over a summer.

Otherwise won't the ice caps at Dartmoor (now known to have existed while before "known" not to have existed) would likewise melt during the summer.

What do you know about "anchor ice"? A rarity, but it occurs for River Avon!

Kostas

Constantinos Ragazas said...

Brian,

As for the glacier transport of pillars, are you still clinking to your "super errotic" followed by "break-up in-transit" theory?

Checking your past post on this (http://brian-mountainman.blogspot.com/2011/10/on-transport-of-pillars.html) we never did get to discuss Bluestone 69. Why such weird contorted shape?

Kostas

Alex Gee said...

Alex Gee:

Brian, Got and read the book. This is excellent news is it not?

The original paper was of great interest, but to have its findings endorsed by the working group must be very gratifying!

Looking forward with amused anticipation to the tortuous intellectual contortions and backsliding the naysayers will shortly be indulging in!

Although its a little early! Can't help thinking that this debate is somewhat similar to the deluge/catastrophe controversy in the 19th century!

Damn those awkward bones/varied rocks in the debitage!






BRIAN JOHN said...

Yes, it looks as if -- after a field trip at which the evidence was discussed by QRA members -- the opposition to Dartmoor glaciation is fading away. There was also a detailed criticism by my old friend Allan Straw -- which was dealt with pretty effectively by Dave Evans and hos colleagues. As I have been saying for a long time, we have to accept that there will have been small cold-based ice caps on all of the hill masses of the SW (including the Mendips) at various times when the Irish Sea Glacier will have been very powerful and extensive. It all makes perfect sense glaciologically.

TonyH said...

Perhaps, as our contribution to increasing the greater knowledge and understanding of our esteemed workers in the Heritage Industry as a whole, we on this Blog should club together with our 50 pence pieces and pay the £18 for a copy of this book. We could send it to the South Western HQ of English Heritage at 29 Queen Square, Bristol. This Office covers the archaeology of all the South Western Counties from Cornwall & Devon to Wiltshire. Knowledge is Power - and, also indeed, Wisdom.

I am sure my fellow Bloggers can think of other individuals or organisations involved in the Bluestone Transport debate who would benefit from reading this book!

Myrsi of Alexandria said...

does cold based glacier have a specific meaningare there warm based glaciers. If yes what is the difference.
Still Dartmoor ice sheets although making a Mendips glacierette more likely does not help solve which tribe moved the stones to Stonehenge.
Is tribe PC? perhaps I should write folk or even polity.
For those watching the Septic Vally programmes the pre-Inka Wari (Huari)were a polity.
M
Just asking!!

BRIAN JOHN said...

Glaciologists traditionally differentiate two types of glacier ice -- temperate or warm-based ice, and polar or cold-based ice. they can exist quite close together, in the same glacier. In the former, the basal ice is above the pressure-melting point, which means that water can be present, and the ice will slide and do a lot of work on eroding the bedrock and moving things about. In the latter, the ice is below the pressure melting point, which means it is frozen to the bed. There will be some movement of the ice near the glacier bed, but the main effect of this scenario is that the ice protects the landscape rather than eroding it. It gets really interesting where there are undulations on the bed -- or valleys and hills -- which means that the ice in one locality may be frozen on, and just a few metres away it may be sliding. Protection, erosion, entrainment, transport.....in some places but not others. It all gets rather complicated!

BRIAN JOHN said...

Kostas -- we are all careless with our typing occasionally, but I really like the one about my "super-errotic" theory linked to the transport of long thin stones. Careful -- this is a family blog......

Constantinos Ragazas said...

Brian,

I fully acknowledge my writing carelessness and spelling erors! Perhaps an edit fixture of your blog for corrections once a post has been submitted?

More to the point. Would you say a local ice cap is more indicative of conditions in an area than a glacial advance into the same area?

Also, if a glacier crossed the Bristol Channel at Somerset and Devon coasts, how far inland would it have advanced? What does the topography tell us on this?

Kostas

TonyH said...

Kostas:

If MPP and his "camp Followers" (and I am NOT talking here about the likes of the U.K.'s Kenneth Williams or Frankie Howerd) still persist stubbornly with their Belief in your super - erotic theory of the transport of long, thin stones, do you explain this by a proto - Mesolithic heroic hunter - gatherer diet of Carrots and Spinach?!

Constantinos Ragazas said...

Tony,

You must credit Brian with the "super erratic" theory of how the bluestone pillars could have been transported by glaciers without breaking up!

And while you're at it, why don't you ask Brian for his explanation for the Bluestone 69 shape! Or about the "empty pits" along the coast and Stonehenge bedrock.

Kostas

BRIAN JOHN said...

Kostas
Not sure why you are so preoccupied with stone 69 -- it's one of those assumed to have been heavily shaped by the builders of the monument -- like the other dolerite stones in the horseshoe. So whatever we make of the shape, we don't know what its "original" shape was -- and we don't get very far on thinking about glacial transport mechanisms.

Constantinos Ragazas said...

Brian,

I would not be making a point of Bluestone 69 were Bluestone 69 was not used to make a point of Neolithic intentions and capabilities.

Bluestone 69 has clearly been worked on and shaped by people. The question is when.

The shape of this stone makes no sense as an orthostat in a Neolithic monument. But it makes great sense as a Roman or Medieval ramming stone in a military apparatuses.

Want to know more? I'd be happy to elaborate if you promise not to block my posts!

Kostas

Myris of Alexandria said...

Ooooaaa!
How apposite, I'm Julian and this is my sandy friend.
There must be a carry on film title in all of this. Carry on punting?
M
Kostas I think carrots came with the Romans we strive for historical accuracy on this blog, and truth, the flag and mom's (sic) Apple pie.
Although in truth I dreaded autumn with Apple trees and a Victoria plum tree all in fruit it was poorly baked pies every Sunday.
M

Myris of Alexandria said...

Whoops it is no Kostas but out Tone who is being naughty. I did think that the blessed Kenneth was unlikely to travel to the USA.
Carrots it seems, like the black death is a central Asian gift.
M

BRIAN JOHN said...

OK -- tell us more, Kostas -- as long as it's on topic....

Constantinos Ragazas said...

Myris,
If the Romans brought the “carrots” to Britain, who in Britain is holding the “sticks”?

Brian,
I assume you are inviting me to discuss my ideas on Bluestone 69? Or are you finally easing your restrictions on what I can comment on on your blog!!!

Kostas

BRIAN JOHN said...

I'm not relenting at all, Kostas. I reserve the right to block any comment from anywhere that is obscene, obsessive, repetitive, disrespectful, or entirely fanciful and lacking in respect for physical laws. That still leaves plenty of room for manoevre.....

Constantinos Ragazas said...

” obscene, obsessive, repetitive, disrespectful, or entirely fanciful and lacking in respect for physical laws”

Thanks for that, Brian! None of this describe my contributions here!

Now, as for Bluestone 69, it would help if we can have a photo of it to make reference. Can you post a photo of it to have such meaningful discussion? Lots to point to here!

Kostas

BRIAN JOHN said...

Thanks Kostas -- these thongs are a matter of opinion, and since it's my blog, my opinion is the one that matters most! re stone 69, I'm afraid I don't have a good pic of it. You can probably find one if you hunt.....

BRIAN JOHN said...

Oooops -- thongs?! These sexual innuendoes are beginning to affect my sanity.......

Cnstantinos Ragazas said...

Brian,

Perhaps some self-censureship is in order here? I see you also lack the ability of editing your comments once you have submitted!

As for a pic of Bluestone 69, you have one in your blog already! Try using your Search feature of your blog to find it. And post it in a current post to have a good discussion of Bluestone 69. It would make my argument more clear if I can point to it.

Kostas

BRIAN JOHN said...

I'm stuck with what Blogger allows me to do -- I can edit posts, but not comments. At least, that's the way it is on the version I use.......

I can preview and then publish, but I'm usually in too much of a hurry....

Constantinos Ragazas said...

Of course. I understand.

What of that pic of Bluestone 69?

Kostas

Geo Cur said...

“I use "sensible"as adjective and not as noun. “
Sensible “ is not (a) noun .
Want to start again .

I have presented you with an argument that you have only responded to with mistakes and nonsense . Pointing out that your arguments ,when you make them , have no support is not the same appealing to a concensus view ,the arguments are refuted first and the lack of support is merely a remarkable statistic .that gets mentioned as an aside and has no bearing on the refutation.
The logical fallacy of the appeal to common sense is favourite of yours usually found in the phrases like “This just does not make sense!” “There are other more sensible ways of explaining all you see “ , “Makes no sense!” “This makes sense.” ,” The shape of this stone makes no sense as an orthostat in a Neolithic monument. But it makes great sense as a Roman or Medieval ramming stone “ This just does not make sense!” These types of comments are not arguments they are meaningless platitudes known as appeals to common sense . Judging by the volume of errors it seems that your sense often lets you down and even in the more reliable general terms common snense is often wrong .