Clyde/Thames Wetlands Archaeology

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Clyde/Thames Wetlands Archaeology

Postby jock78 » Tue Feb 24, 2015 8:26 pm

There are a number of parallels between the two rivers as indeed there are by many other rivers since the end of the ice age. they have all been subject to the sea levels into which they decant having risen at stages by a total of 60 metres. this, in turn has affected their gradients resulting in meanders, deposition of aluvium and a wide basin of 'wetlands' which have only been constrain within banks in historical times.
Since the industrial revolution, this containment has been by sheet piles but prior to this, largely in a piecemeal fashion often by beaching old hulls at high tide, filling them with, usually rubbish and the land on the foreshore behind to form an impromptu jetty.

I know this because I have worked at London Docklands redevelopment as an engineer in the 80s and before this in planning pumping works for Chatham to contain abnormal tide and river levels.
Over the years, I became aware of succeeding raised wetlands found by a geographer Dr Devoy who presented a paper in 1979 to the Royal Society. He calls these levels Tilbury I- IV, the highest two of which, Tilbury III and IV being in the neolithic and bronze age respectively. Tilbury being where he found the levels of marine and organic materials which could be dated
.
Since then, and largely due to recent planning legislation (PPG16), these levels have offered up habitations such as crannogs and trackways. Strangely enough, some have been found at planned new Tesco supermarkets where a large site is necessary at for instance at Dagenham and Rainham, also in Docklands at Beckton.

The use of old boats as wharfage may be much earlier than would be imagined- at Govan General Terminus, a number of early boats have been found in a line behind the current river walls. Also at Southampton and Hull. I may have cut through one myself in 1955 at general Terminus as a young student apprentice with British Railways in digging a main drain for a new ore bunker there!

Other well known examples are in New York on the Hudson found in the seventies and another one recently at the redevelopment of the World Trade Centre site.

Looking at the Clyde, The presence of a number of islands downstream of Glasgow is well known, the former crannogs on the foreshore and old maps show that the river had wetlands on either side, see the convoluted course of the Molendinar south of Duke Street and the Clyde's meanders upstream of this.

John
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Re: Clyde/Thames Wetlands Archaeology

Postby jock78 » Tue Mar 10, 2015 4:56 pm

Glasgow alluvium.docx
wide area of alluvium either side of the Clyde
(1.51 MiB) Downloaded 93 times
Further to my note on the possibility of 'wetlands', I attach an extract of drift geology which shows a large area of alluvium on either side of the Clyde through the city.
I have previously mentioned the old boats found well behind the quay at General Terminus at Govan. The detail of these can be seen in 'pastmap'. Also in pastmap is reference to a canoe which was found at Drygate at an elevation of 25 metres!- as the river is at about zero AOD below the Saltmarket bridge. how did it get up there? Must have been a flood!

Devoy's paper on the Thames identifies 4 periods of sustained higher sea levels over the past 10,000 years. He calls them 'Tilbury I to IV'. these are well accredited by Museum of London indeed I have seen Tilbury IV, the highest of them, exposed in construction work on the Isle of Dogs while working at the redevelopment there.

My contention is that these same sea rises and falls should be present also in the Clyde and on other rivers at least around the UK.
What i need is some borehole records through the river terraces. These in turn, would show narrow bands of organic material as evidence of higher river and sea levels.
Can anyone help?

John
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Re: Clyde/Thames Wetlands Archaeology

Postby Grahame » Wed Mar 11, 2015 9:06 am

Hi John,

Have you tried playing with the borehole layer on the BGS interactive map?

Not all of them have freely available records, but many of them do; although I don't know if they'll have the sort of archaeological detail that you're after. Worth a look though.
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Re: Clyde/Thames Wetlands Archaeology

Postby jock78 » Wed Mar 11, 2015 4:38 pm

Hi Grahame,
These looks to be very useful on a preliminary view.
There is a lot to go through but as I would think peat layers would be important and highlighted as these could require to be dug out in some cases.
Did you manage to read Devoy's report? -it is on line. It looks as if he had new boreholes sunk on the line of previous engineering bores so that he could get the detail of marine organisms and do carbon 14 tests on the peat layers. His figures are a bit rough as he did not have the benefit of a computer!
What was a complete surprise was the 'wetlands' stuff that came to the fore over the past 25 years as a result of the new planning legislation PPG 16 or its more recent version.

The other, unrelated issue that I am pursuing is that of previous river walls behind current ones including use of old boats. Trig lane excavations in the city of London shows 600 years of river works built progressively one in front of the other running back many metres.


Thanks again for your interest- I realize that archaeology is not everyone's cup of tea but very much 'hidden Glasgow'!

John
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Re: Clyde/Thames Wetlands Archaeology

Postby jock78 » Sat Mar 14, 2015 4:32 pm

Apologies

Hi all it looks as if I have been up a blind alley with this one.

I did not account for the 'isostatic adjustment'. That is what happened when the weight of ice melted off causing the land to 'float' upwards, which, in turn changed the relative levels between the sea and the land at least in Scotland.

You can still see the 6,000 year old tree stumps however in the Solway if you walk out at low tide. This is equivalent to the 'Tilbury III level on the Thames. These have been shown also on the 'Coast' programme off many areas of England.

What we have apparently, are 'raised beaches', 3 of them in some cases but not obvious, however, on the Clyde- How they relate to Devoy's 'Tilbury levels' I do not know. Maybe I should look at these but this does not pertain to Glasgow.

I am still interested in the use of old boats for wharfage and raising river banks- the line of these at General Terminus in Govan seems significant - it is too much to expect that a number of people dumped their old ones in a line there! And what guy climbed up the Drygate to dump his 25 metres up from the river!

Pleae tell me if this is not of interest.
John (nearly jock79 this month)
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Re: Clyde/Thames Wetlands Archaeology

Postby Lucky Poet » Mon Mar 16, 2015 8:37 pm

Hi Jock,

I must confess it crossed my mind that the land has been rising here (I'm assuming 'isostatic adjustment' and 'post-glacial rebound' amount to the same thing).

For myself, it's not that it's not a subject of interest - it is! It's that I know very little of it, and don't feel that I can contribute much, because I feel quite ignorant of all but the basics. About all that I know is that the level of Dundee High Street is thought to be a raised beach.

The talk of old boats brings to mind this though, in New York of all places:
http://www.nbcnewyork.com/news/local/Sh ... 94754.html

(Apologies for it being from a slightly crappy news source, but it's still interesting. Clearly using old boats for consolidating shorelines was a widespread idea.)
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Re: Clyde/Thames Wetlands Archaeology

Postby jock78 » Tue Mar 17, 2015 11:18 am

Hi Lucky Poet,
I'm not really trying to 'one up' you but I first became interested in the old ship issue by reading in a book 'History from the Sea' about 30 years ago.
It described a complete 18C ship's hull found in Manhattan in 1982. Search on google, 'The ship that held up Wall Street' ( sorry I am not good at highlighting links).
This was found by a developer, Howard Ronson -it was in good condition but so heavy that they only salvaged the bow section and left the rest- I trust this was not the same one as that at The World Trade Centre site!
Thanks for your comments, I will continue to write on such matters.

I know a little about 'wetlands' as I have worked at London Docklands in the eighties and in Borneo in the nineties. I am no expert but a wee bit of lateral thinking and tongue in cheek gets me through.

There are indeed a smattering of information on old ships and boats behind river banks but the their location is such that they are only found when works are carried out there.

About archaeologists- I think that the nature of their training precludes them against speculating but as laymen or women We are not so encumbered!

I will keep on speculating but it is nice to have feedback,
Best regards,
John
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Re: Clyde/Thames Wetlands Archaeology

Postby jock78 » Tue Mar 17, 2015 4:41 pm

PS,
The ship found on the Hudson in 1982 was a tobacco ship so likely to have been no stranger to Glasgow!

John
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Re: Clyde/Thames Wetlands Archaeology

Postby jock78 » Fri Apr 03, 2015 1:15 pm

Grahame wrote:Hi John,

Have you tried playing with the borehole layer on the BGS interactive map?

Not all of them have freely available records, but many of them do; although I don't know if they'll have the sort of archaeological detail that you're after. Worth a look though.


Hi Grahame,
I've checked these out now - and I have found some peat layers 10-15 cms at 7-8M OS datum in some of these ( suspect many others have been missed as just part of the 'made ground' element..

. also At Glenacardoch Point there are a number of raised beach platforms shown for the Lower Clyde which illustrate different ages when the higher sea levels have been sustained for some time.

As the land has been steadily rising at 1-1.5mm per year then this represents 6-9 Metres over the past 6,000 years.

It as apparently well established that sea levels were 5M higher 7,000 years ago, this was sustained for about 1000 years before falling to about the present level.

This would, presumably, be the same level found on the Thames (Tilbury III) and ancient tree stumps which appear at low tide on the Solway and throughout the coast south of there.

Could the thin peat layers beneath Glasgow be the remnants of this 7K raised sea level?

All a bit too complicated for me but worth trying!

John
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