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Newgrange: quartz and granite wall
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tiompan
tiompan
5758 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 19:50
Without the steel reinforced concrete support the wall would collapse .

Quartz is not exclusively associated with Neolithic monuments , it is found throughout the EBA to LBA too and possibly more common in the BA .
The more recent Lynch and Sweetman excavations show that there was post Neolithic activity in the area of monument, exactly as is found at other major monuments including reworking of older material e.g. Stonehenge etc and also noted locally by Eogan at Knowth . Later BA use of the sites , and or reworking , of earlier monuments is the norm .

Yes the pic shows that the quartz that makes up the wall is nothing like the walling found in other monuments . Quartz is far from ideal because it doesn’t fracture along structural planes and produces far from rectangular slabs that are useless for walling .
"A good quantity" of the original quartz that was discovered " was shattered and could not be used " on the facade , coupled with the much greater extent of the facade compared with what O 'Kelly describes , much of what we see must have been imported for the job .
GLADMAN
949 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 19:58
tiompan wrote:
Without the steel reinforced concrete support the wall would collapse .


That has always been my understanding. From a purely engineering point of view, are there any known prehistoric structural techniques that could have achieved the façade we now have?
CianMcLiam
CianMcLiam
1067 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 20:05
It could also be said that the near vertical walls at Gavrinis, Petit Mont, Barnenez etc. would have never stood, but sections of these were found in situ.

It's often been claimed that quartz had to be brought to site by O'Kelly. I've discussed this with several people involved in the dig and just a couple of weeks ago Geraldine Stout made clear in a public talk on Newgrange that all quartz used at Newgrange was found on site, none was brought in. Claire O'Kelly also pointed this out in no uncertain terms to a guide there in the early 80's who claimed in front of tourists that some of the quartz was brought in during the excavations.

Ann Lynch's excavations seems to bear this out, she found a quartz layer further back around the mound. The current quartz wall peters out before it gets this far, so the unusable quartz only meant that the quartz section could not wrap around as far as it did originally.
CianMcLiam
CianMcLiam
1067 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 20:07
GLADMAN wrote:
tiompan wrote:
Without the steel reinforced concrete support the wall would collapse .


That has always been my understanding. From a purely engineering point of view, are there any known prehistoric structural techniques that could have achieved the façade we now have?


Yes, similar walls were found at Petit Mont, Gavrinis, Barnenez etc. A good intact section of similar walling can still be seen at Baltinglass Hill.
GLADMAN
949 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 20:33
CianMcLiam wrote:
GLADMAN wrote:
tiompan wrote:
Without the steel reinforced concrete support the wall would collapse .


That has always been my understanding. From a purely engineering point of view, are there any known prehistoric structural techniques that could have achieved the façade we now have?


Yes, similar walls were found at Petit Mont, Gavrinis, Barnenez etc. A good intact section of similar walling can still be seen at Baltinglass Hill.


I'm aware of the Brittany monuments - although sadly not been.... yet - but not aware of any of those using quartzite in a load bearing context? Question is why O'Kelly had to use additional structural support? Would such a quartzite façade stand without the modern help?

In my experience Quartzite is a pretty consistent feature - albeit in small quantities - of upland Bronze Age cairns across the UK so clearly it had a pretty widespread symbolic (?) value; however, to my knowledge, nowhere is it used in a load bearing context
tiompan
tiompan
5758 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 21:08
GLADMAN wrote:
tiompan wrote:
Without the steel reinforced concrete support the wall would collapse .


That has always been my understanding. From a purely engineering point of view, are there any known prehistoric structural techniques that could have achieved the façade we now have?



With that type of material , and the fact that it is vertical ,I don't believe so .
tiompan
tiompan
5758 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 21:17
CianMcLiam wrote:
GLADMAN wrote:
tiompan wrote:
Without the steel reinforced concrete support the wall would collapse .


That has always been my understanding. From a purely engineering point of view, are there any known prehistoric structural techniques that could have achieved the façade we now have?


Yes, similar walls were found at Petit Mont, Gavrinis, Barnenez etc. A good intact section of similar walling can still be seen at Baltinglass Hill.


They are not similar . The walling consists of rectangular slabs which are totally unlike the stones /cobble shape of the quartz .
CianMcLiam
CianMcLiam
1067 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 21:42
Not sure I'd call them rectangular slabs, most use a variety of shapes and sizes, from very small stones to maybe a foot or so max.

Here's Barnenez: https://www.dropbox.com/s/ba02wpuquxr04hy/80063000.jpg?dl=0
Petit Mont:
https://www.dropbox.com/s/865u2ebuz6r831w/untitled.png?dl=0
CianMcLiam
CianMcLiam
1067 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 21:44
Yes, the quartz found on the cairns at Loughcrew, and collapsed off the mounds of Newgrange, Knowth and Knockroe seem to be an Irish thing. So are basin stones, the roofbox, the boulder cap over the chamber of Newgrange and the fairly unique style of art.
tiompan
tiompan
5758 posts

Re: Newgrange: quartz and granite wall
Jul 17, 2016, 21:45
There is no problem about the walls standing at Gavrinis , Petit Mont, Barnenez etc.. They used walling , something entirely different from quartz cobbles ,and suited for the job .

It shouldn’t be difficult to work out the volume of quartz used in the façade then compare it with what had been discovered at the site .
O’ Kelly commented “"A good quantity was shattered and could not be used " on the facade ,and how the volume " decreased gradually in amount and extent " ,whereas the facde maintains a solid homogenous wall . Where did it come from ? It doesn’t quite add up .
If nothing else it shows that what see was not typical of the finds .But even what we see ,i.e. the more usable stuff , still needs the steel and concrete to stay up .
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