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Widecombe History Group Talk October 2004
Notes on a Talk on Dartmoor after the Ice Age
by Roger Claxton
Pictures used in the talk are not currently available online. we may be able to remedy this in the future.
Welcome to the talk. Geoffrey Weymouth recently stood here and said it was his 508th talk. I had a bit of a think about this and worked out that this was my 2nd. Hmmm. I am suitably humbled. I hope a few of you are still here at the end!
This talk covers the period from the end of what we commonly term the Ice Age and approximately 5,000 BC.
The aim is to try to provide a feeling (mainly visual) of what Dartmoor might have been like during this period of our history.
I cannot claim it to be all my own work. In fact it has arisen mainly out of a University of Exeter course that I did entitled ‘Human Environments in Prehistory’, a couple of books:
- The Holocene
- After the Ice
- DAS Journals
- …and some of my own internet searching and other investigation.
I will be showing quite a few illustrations, mainly picked up from the Internet that represent how Dartmoor and Devon could have looked when under the climatic conditions to be discussed in many cases by reference to other parts of planet earth that today experience similar climatic conditions to that of Dartmoor after the Ice Age.
I want to start by putting the Ice Age into some sort of context.
Firstly, ‘The Ice Age’, as we commonly refer to it, is really the last Ice Age. There have been a series of Ice Ages approximately one every 100,000 years, with warmer periods in between. We are currently in one of these warmer periods (whether we have changed this pattern for ever with global warming is another subject entirely !).
This picture, taken from Current Archaeology’ magazine shows these Ice Ages quite well with the periods of warmer and colder weather occurring even within glacial and inter-glacial periods.
Picture 1. Timeline
Note the evidence of people. Also mention importance of Kent’s Cavern and Pengelly Cave.
Also at the end of the Ice Age the ice cover did not disappear overnight. There was a gradual warming, with a number of ‘blips’ when it became quite cold again. In fact the Last Glacial Maximum, as it is called, i.e. the period when the ice was at its maximum extent occurred c 18,000 years ago and it gradually receded after that.
This picture shows the area covered by ice at the LGM.
At the time of the lowest sea levels land extended unbroken from Land’s End to the Southern tip of South America and to Borneo and Java.
Picture 2. LGM
Both the North Sea and the English Channel are relatively shallow. This picture of the Continental Shelf shows this clearly. You can see the similarity between the LGM sea levels and the Continental Shelf, not surprisingly.
Picture 3. Continental Shelf
We need to think of the channel and the North Sea as, in effect, relatively low-lying plains, with today’s mainland Britain (and France) as high ground. With the channel no more than 600 feet deep the overall climb from the lowest point to today’s shoreline was no more than the climb from shore to somewhere like Holne or Owlacombe Cross.
There must be an awful lot of archaeological remains buried under water.
As we know Dartmoor was not covered by ice although it got pretty close and the ground must have been hard, the weather cold and generally the area must have been fairly inhospitable (although it must also have been beautiful at times).
There were probably a small number of humans in the area – there is evidence of man from Kent’s Cavern dating to 31,000 years ago – so they were around, but were probably few in number and would need to be cave dwellers probably.
The Glacial animals such as Mammoth, woolly rhino, reindeer and Giant deer were dominant (evidence of mammoth and woolly rhino found at Kent’s Cavern).
Mammoth – skull found in a gravel pit nr Swindon (as you will know if you watched Alan Titchmarsh last week).
The area just beyond the ice can best be described as Tundra or Steppe-Tundra, roughly equivalent to sub-Arctic conditions today and Devon as a whole must have been like that with few trees (maybe some dwarf willow, hazel, birch etc) and a predominance of grasses, hardy plants, some dwarf shrubs etc. (e.g. Iceland Purslane, Mountain Sorrel.
Pictures 4 and 5 : Late Glacial Plants.
Note the climate: generally it is thought it was drier than today, with rainfall (precipitation) mostly falling as snow.
So what did the land look like? One way to get a feel for this is through other parts of the world that have similar climatic conditions. Not surprisingly, Alaska and parts of Siberia provide the best examples – so this gives you an idea of what living here would have been like.
This is a picture of some Tundra.
Picture 6. Tundra
We can also note that the coastline was very different to today and changing as the ice melted. The sea level was originally much lower and what we know as ‘Britain’ was connected to the mainland of Europe. This is important for the flora and fauna that would populate the area as conditions improved. While Britain remained connected, it was easier for flora (and fauna) to spread from mainland Europe. As the connection (land bridge) reduced in size this would make it more difficult and eventually really difficult. The same applies to the people who would have moved north-west from Europe (although they did use boats of various kinds).
Picture 7 of coastline.
After the LGM, as the ice gradually receded, conditions must have slowly improved
As a slight aside, there were some interesting side-effects of the receding ice. Firstly, as the ice melted and its weight was removed, some rocks rose up, in some cases this rise exceeded the rise in the sea level. This is a picture of cliffs in western Scotland where this phenomenon occurred
Picture 8 of Scottish cliffs.
In other areas such as the Low Countries, there was a see saw effect with some land rising while others actually fell.
As the weather improved and tree cover increased. So Britain began to be populated by new kinds of animals:
The Glacial animals such as Mammoth, woolly rhino, reindeer and Giant deer (evidence of mammoth and woolly rhino found at Kent’s Cavern) gave way to the tundra animals (reindeer, elk, horse etc) which were themselves then displaced northwards and these took their place:
- Red Deer
- Roe Deer
- Wild Boar
In 1996, after a storm, blue-grey silts were exposed on the beach at Porlock Weir, Somerset. From these silts, parts of a skeleton of an aurochs or wild cattle, were found. Radiocarbon dating shows that it dates to the Bronze age, more precisely to BC 1738-1450 (calibrated). After analysis the individual was identified as being male and at least 10 years old. The find from Porlock shows a number of interesting pathological conditions, involving trauma, infection, and age-related degeneration.
10,000 BP 11,000 BP 12,000 BP 13,000 BP
- Newest Period:
- More open tundra-like. Arid. Wild grasses.
- Wild horse and reindeer
- Middle Period
- Closed birch and willow woodland with mosaic of herbaceous scrub.
- Red deer, elk and roe deer.
- Oldest Period:
- Open herb-dominated plant communities.
- Mammoth, woolly rhino, reindeer and Giant deer.
trees and shrubs.
Open woodland – Birch scrub
The tundra (open but with some small bushes, e.g. dwarf birch) accommodated certain types of animals (e.g. the horse and reindeer), which dominated the area of landscape outside the ice-sheet at 11500 BP,
This open landscape is illustrated in the pollen diagrams from Black Ridge Brook which show a landscape dominated by herbs (grasses) and shrubs such as willow (probably dwarf), with trees gradually increasing in number.
As the climate improved, the area of Dartmoor (in fact the whole of UK) began to be forested, initially with birch trees and pine and later with deciduous trees (Roberts 1998: 101), which spread from the south (e.g. hazel, elm, and later oak, lime, alder and ash). Different types of animal appeared (red deer, aurochs, wild boar) and edible plant species greatly increased in number (Roberts 1998: 109).
Pollen diagram from Unit 3 shows this progression.
Also pollen grain pictures to illustrate the process.
On Dartmoor, a similar pattern must have occurred. At 7000BP, the tree line would probably have been at 500m, thus all but the highest parts of the moor would have had tree cover.
See paragraph from Into the Mists page 39.
Picture: Contour map of Dartmoor with land above 500m highlighted
The population also increased, presumably by migrants venturing from the east and south east and a hunting fishing gathering (HFG) economy grew up.
As the weather improved and population grew probably as a result both of further immigration and communities increasing in number it must have became harder and harder to successfully adopt a HFG approach and farming became a natural development. E.g. why go off looking for animals when you can enclose them and get one whenever you want/ you can also look after them to increase their number. Also word of crops that could be grown and harvested would also have spread from the east ( we assume this from the fact that farming appears to have taken hold in the near east first and spread across Europe from that direction).
Farming requires enclosed land and land that has at least to an extent been cleared of trees (although the value of woodland would also have been recognised – wood is a valuable raw material – and so woodland would also have been ‘managed’ at this time).
Pinswell Site near Fur Tor
(Note: this is one site – different sites will show different patterns and will occur at different times)
There is evidence of burning at c 6750 BP at the Pinswell site. Although we cannot be absolutely sure this was purposeful burning, it seems likely even though there may have been natural causes as well (e.g. lightning strikes). It could also have been local burning that got out of hand. However it does occur over a large period of time.
Once cleared, regeneration of woodland would probably have been prevented to an extent by grazing animals, while this continued to be practised. The result was a grassland habitat unlike that of today – a wet, relatively tall grassland with pH no lower than 4.5 – common sorrel and greater birds foot trefoil have been identified. Also common sheep sorrel.
- Lotus uliginosus (birds foot trefoil).
- Rumex acetosa (common sorrel) & acetosella (sheep sorrel) (sim to today where swaling and/or intensive grazing is practised).
- Melampyrum pratense – common cow wheat
The layer(s) of charcoal left by burning would act as a barrier to drainage, keeping the surface damp in the relatively wet climate. Absence of trees would also prevent the natural transpiration process provided by trees
Pic of tree/water processes
The dampness means that the sphagnum presence will continue and overall the ground will be relatively species poor. The build-up of moss and decaying matter (dead bits) further clogs the ground and prevents drainage.
Even though burning appears to have stopped c . 6300 BP, tree cover did not return. This cessation of burning is thought to indicate virtual abandonment of the area by Neolithic farmers – and by this time moss build up was too much to allow woodland recovery – probably connected with increased wetness of the climate (climate deterioration).
So on the upper moor we have the formation of blanket bog and this map shows the current extent of it (from Dartmoor – A New Study).
Partly in summary, it is instructive to look at the Rimsmoor pollen diagram. This offers a good summary of the British floral preponderances over the last 10,000 years or so.
The next stage on Dartmoor ushers in the great period of monument building, which must remain the subject of a future talk.
Pics of monuments – merrivale etc
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