Saturday, 17 September 2011

The Somerset Levels - Yet another Paradox?

By Robert John Langdon

The Somerset flats are a strange paradox to any rational person studying the area.



A paper by the Somerset County Council on the Palaeolithic and Mesolithic Period clearly states that;


The Early Mesolithic (as defined for present purposes) covers most of the first “epoch”. In the Late Glacial and Early Holocene, the ameliorating Palaeolithic and Mesolithic climate was reflected by a rapid rise in sea level of c.1cm per year, with a drop in this rate after c.7000–6500 BP (c.5990–5350 cal BC). 


Sea level rose from c.35m below present mean sea level (MSL) at c.9500 BP (c.9130–8630 cal BC), reaching c.5m below MSL in the Bristol Channel by c.4000–3800 cal BC (the rate of rise having slowed by c.4000 cal BC).


At the time of the Mesolithic, the Somerset Plain was between 5m and 35m above the sea level - so why was it flooded?

Lets see what Wikipedia makes of this paradox?


The Somerset Levels, or the Somerset Levels and Moors as they are less commonly but more correctly known, is a sparsely populated coastal plain and wetland area of central SomersetSouth West England, between the Quantock and Mendip Hills. The Levels occupy an area of about 160,000 acres (650 km2), corresponding broadly to the administrative district of Sedgemoor but also including the south-eastern part of the Mendip district. The Somerset Levels are bisected by the Polden Hills; the areas to the south are drained by the River Parrett, and the areas to the North by the rivers Axe and Brue. The Mendip Hills separate the Somerset Levels from the North Somerset Levels. The Somerset Levels consist of marine clay "levels" along the coast, and inland (often peat-based) "moors"; agriculturally, about 70 percent is used as grassland and the rest is arable. Willow and teazel are grown commercially and peat is extracted.
One explanation for the county of Somerset's name is that, in prehistory, because of winter flooding humans restricted their use of the Levels to the summer, leading to a derivation from Sumorsaete, meaning land of the summer people. A Palaeolithic flint tool found in West Sedgemoor is the earliest indication of human presence in the area. The Neolithic people exploited the reedswamps for their natural resources and started to construct wooden trackways, including the world's oldest known timber trackway, the Sweet Track, dating from the 3800s BC. The Levels were the location of the Glastonbury Lake Village as well as two Lake villages at Meare Lake. Several settlements and hill forts were built on the natural "islands" of slightly raised land, including Brent Knoll and Glastonbury. In theRoman period sea salt was extracted and a string of settlements were set up along the Polden Hills. 


Winter Flooding - so how do we know that?

The most Recent paper my Dr Richard Brunning shows that in 8300BC the entire region was covered with over 100 islands

Somerset Flood Plain
But if the Sea level was below the land surface - by at least 5m, how did it flood, even in winter?

The amount of rain needed to flood this area is equivalent to a far eastern monsoon - and if it rained that much in Somerset, it must have rained the same throughout Britain?

The only logical answer is that the rivers feeding this 'delta' were flooded with excess water from the ice age that had raised their water levels by about 30m.  This would allow sufficient water to flood the Somerset Levels before flowing into the Sea some 5m below the land level.

Yet another proof of my hypothesis and how it changed the course of our history.

RJL

(by Robert John Langdon)

11 comments:

  1. Robert

    You state the 100 islands were 8300BC but the image states 5000BC - which is correct?

    Dr Stuart Love

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  2. Stuart

    These are dates and illustration supplied by Dr Richard Brunning of Somerset Country Council.

    I believe the 8300BC date relates to the carbon dating of two skulls found on one of these 'islands' when over 100 islands existed - the diagram dated 5000BC was later when some islands must have disappeared.

    RJL

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  3. Robert,

    You write,

    “The only logical answer is that the rivers feeding this 'delta' were flooded with excess water from the ice age that had raised their water levels by about 30m.  This would allow sufficient water to flood the Somerset Levels before flowing into the Sea some 5m below the land level.”

    I agree that rain water alone would not account for the flooding. But there is another explanation to this 'Somerset Levels dilemma'.

    If the waterways that formed following the glacier melt were frozen during the Devensian. Then the rain water overflow on top of this would result in flooding.

    Good post!

    Kostas

    ReplyDelete
  4. Kostas

    It would indeed!

    But only temporary and only if it effected the groundwater table.

    The Somerset Plain lasted over 9000 years until drained in the late Medieval period.

    RJL

    ReplyDelete
  5. Brian blocked my response to you in his blog, so I am posting it below!

    I wish he would stop interfering with the free flow of ideas and skewing the argument by leaving the other side 'blank'! In my case, he seems to block my best arguments! What is he afraid of? But if he chooses to block a follow-up response, at least he should post that he blocked the response. It's the honorable thing to do!
    -----------------------------------------
    Robert,

    I especially liked your account of your chance meeting with MPP at Bluestonehenge! In a nutshell it captures the 'avoidance of evidence' if the evidence contradicts vested ideas. It's more than just an intellectual exercise! It is a physical reaction, no less so than the “fight or flight” instinct. Obviously, in the case of your MPP encounter, “flight” took over!

    But picking up on you comment to me about the Avenue, you write

    “The ditch/moat on the N/W side is deeper than the ditch/moat on the S/E if it was due to water flow it would be the other way around, as their is a natural slop at that point from NE to SE.”

    Two points to make on that here:

    1)The meltwater stream over the ice cover I am hypothesizing would be coming mainly from the N/W direction. The same as the direction of the glacier advance/retreat Brian has argued. You would expect the volume of water fall to be strongest in that direction and lesser further down in the direction of S/E. So my theory is again consistent with the 'facts on the ground'.

    2)The “natural slop” of the land has absolutely no relevance here, since we are hypothesizing an ice sheet cover. The surface of a frozen lake (for example) is perfectly flat; whereas the lake bottom can be very uneven and sharply sloped.

    You further write,

    “The avenue ends abruptly, if it was natural it would end gradually.”

    I assume you are talking about the straight stretch of some 500 meters of the Avenue before is abruptly veers off in the direction of River Avon.

    But I have already explained why that happens. The straight stretch of 500 meters began as a meltwater channel on the surface of the ice sheet; starting at a retaining cylindrical ice basin at Stonehenge. The direction of the greatest solar radiation (which happens around summer solstice) determined the direction of this meltwater channel.

    At some point, this water channel would seek and find its way to the nearest river to drain. That's what accounts for the abrupt veering off towards the River Avon.

    As for “ The Periglacial Striations within the avenue”, these also have a simple explanation in accordance with my hypothesis. As the meltwater channel on the surface of the ice sheet got deeper, it eventually exposed the underlying soil. At this point it was a small stream. And of course, even with the normal periglacial conditions in the area and seasonal freezing during the winters (no need for a mini ice age!), this exposed soil will develop “ The Periglacial Striations within the avenue”. This also explains why no such striations can be found elsewhere but within the avenue. Since the rest of the landscape was still covered by ice and so protected.

    You asked! I answered!

    Kostas

    ReplyDelete
  6. Kostas

    Although a 'robust' answer it still leaves the question about why 'The Avenue' when it turns after the elbow losses its ditches and periglacial Striations - surely this shows two separate phases?

    If so why end at the elbow?

    On question 1

    Does this flow stop at the Avenue? If not the power of the flow would have been equal surely?

    On the Periglacial Striations - why are they visible ONLY on the Avenue and not in Stonehenge bottom were the ice came from?


    RJL

    ReplyDelete
  7. Robert,

    I believe River Avon may at one time have been up to the point where the Avenue veers off. That's one scenario, but I can think of others. If so, that part of the Avenue between the 'elbow' and River Avon possibly formed latter. When the River retreated into narrower banks.

    That would explain why there are no 'ditches' in that part of the Avenue and why there are no periglacial striations. The meltwater stream over this section of the Avenue would be less defined following the landscape contour. I have not seen this area myself and so its hard to know for sure.

    Stonehenge Bottom has no striations either because it was under ice or under water and possibly both at different times.

    Kostas

    ReplyDelete
  8. Kostas

    We are in agreement on the river - the striations are a mystery which I must confess the geological 'experts' at Stonehenge thoughts have failed to answer, which is disappointing.

    The original excavators thought they were track marks for carts - if no geologists can show me why they can be periglacial striations - I just may have to spend some time comparing them to the cart marks found in other prehistoric sites in Malta.

    RJL

    ReplyDelete
  9. Robert,

    We agree on many things! It's our disagreements, however, that define us.

    Whereas you believe Mesolithic people build these prehistoric monuments; I believe Nature had a far greater role.

    Whereas you believe Mesolithic vast waterways provided the transportation means for Mesolithic boat people; I believe that these waterways were frozen at the time and ice provided the natural means for the transport of stones.

    Whereas you see human intentionality and purpose in the formation of these earthworks; I see the intentions of Nature with men simply exploiting what Nature has already provided.

    Kostas

    ReplyDelete
  10. More Wikipedia and doctoring the work of others to suit your hypothesis. If I didn't know better, I'd say you were a first year Geography student.

    ReplyDelete
  11. Anon

    I love Wikipedia and the internet as it upsets academics who believe they should have control over knowledge.

    First year Geography student - I wished - I'll be out having fun instead of texting to idiots like you.

    If you have a problem with the content, just says so and I will assist you through your ponderous thought processes. If your bored and just want to be juvenile - do us all a favour and go play with the traffic.

    Power to the people!

    ReplyDelete