Day Trip to Grimes Graves, Norfolk

Dog-sitting duties yesterday for this old fellah:

12 years old, and with a large out of control tumour on his back, it was awesome to take him into the forest again, even though he ran away - just like he would as a young dog.  He had me running around this monument looking for him:

Thetford Warren Lodge, the handsome ruin of a medieval rabbit warrener's fortified house.  Possibly commissioned by the nearby Prior of Thetford Cluniac Priory.

After our little adventure, I dropped the dogs off to keep cool during the mid day, and then took the opportunity to revisit an awesome prehistoric site in the Thetford Forest area, the Neolithic flint mines at Grimes Graves.  It use to be a regular haunt of mine.

This is an aerial view of the site.  An almost Martian landscape of craters and earthworks.  Surveys have recorded a total of at least 430 shafts sunk into the ground.  Each reaches down to a seam of black flint known as floor-stone, about 10 meters down from the surface.  Shallow galleries then radiate along this layer of floor-stone flint in all directions.

Until excavations revealed the nature of these craters during the 19th Century AD, no one knew what this landscape represented.  The Anglo-Saxons named it Grimes Graves, after the god Woden (Grim). They set all of the local parish boundaries to meet at the site, where they erected a moot hill, a meeting place for the hundred.  Later antiquarians suggested that it was the site of Danish encampments.

We now know that these craters are the scars of a remarkable flint mine complex, that was in use during the Neolithic period between 4,675 and 4,200 years ago.  Each year, an average of one shaft was mined.  The tools that they used appear to have consisted largely of picks made from red deer antlers, stone axes, and tools made from wood and basketry.  So many red deer antlers appear to have been used, that it has been estimated that they will have needed to manage a population of 120 red deer in order to supply them!

One shaft is presently open to the general public, but there are plans to reopen another shaft later this year.  The English Heritage site has a small museum and presentation on the site:

From there, you can walk over to Pit 1, the shaft open to the public.

Descent to the floorstone level is via a sturdy 30 feet ladder.

The galleries themselves are not open to public access, for reasons of safety.  However, you can enter some of them a short distance before reaching barriers.

It is a little bit of a mystery as to why they were going to such dramatic and exhaustive efforts to mine this flint over a 475 year period.  There is plenty of good flint much closer to the surface, even on the surface.  However, the floor-stone flint has a particular fresh looking, black colour and quality.  It may have even had a ritual value, for coming so far deep out of the earth, and even for being so difficult to mine.  Here's a reconstructed Neolithic axe that I could play with, made of local black flint.

I got a little dirty crawling through the galleries.  Notice the exposed chalky spoil on the surface.  Moved there thousands of years ago by the Neolithic miners.

It's a beautiful place, the Martian looking craters, spoil heaps, often grazed by sheep, and nested on by larks.

I thought it was also recording that Anglo-Saxon moot-hill on the edge of the site.

Discussion - Population Genetics

Okay, so where does this site sit in with the latest news in population genetics?  The population that mined this site for so many years, was most likely (based on ancient DNA from other British Neolithic sites) largely descended from farming immigrants from the South, that arrived in Britain some 6,100 years ago.  The men most likely had I2a Y-DNA haplogroups, and the population today that most resembles them today are the Sardinians.  Their ancestors may have migrated from Iberia, but ultimately, some of their ancestors at earlier dates, had moved along the Mediterranean from an origin in Anatolia and the Levant.  They brought with them, the technologies, livestock, and seeds of the Neolithic Revolution, that had exploded in the Fertile Crescent of the Levant, and the Tigris / Euphrates valleys some 10,000 years ago.

The mining stops around 2,800 years ago.  This corresponds well with what we now believe to be the arrival of a new people - the Bell Beaker People, that had crossed the North Sea from the Lower Rhine area around what is now the Netherlands.  They most likely brought with them, the first horses, and the first metallurgy of copper, bronze, and gold.  What happened to the Neolithic community that had mined for so many years here?  There is some evidence that their economy was falling into trouble, and that forest was returning to many farmed areas.  They may have had their population and social structure depleted by a suspect plague that had reached Western Europe from Asia.  The latest evidence, as presented in my last post, The Beaker phenomenon and genetic transformation of Northwest Europe 2017, suggests an almost complete displacement of the British Neolithic farmers by this new population of Bell Beaker.

Thetford Forest Archaeology

The value of the floor-stone flint appears to have fell.  However, it is a fallacy to believe that people stopped using flint.  The new metals were precious, but flint continued to have an importance through the Beaker, and into the Bronze and even Iron Ages.  It has been speculated that the majority of struck flint in the district actually dates to the Beaker and Bronze Ages, rather than to the Neolithic.  Thousands of tonnes of flakes, hammer-stones, piercers, awls, scrapers, notched flakes, and waste cores can be found in the soils to the south and west of Grimes Graves - down to the northern banks of the Little Ouse, and across the Brecks district, and the Fen Edge.  Many years ago, I found a barbed and tanged flint arrowhead very, very close to the Grimes Graves site.  This class of arrowhead belongs to Bell Beaker assemblage.  They were here, salvaging the tonnes of discarded flint on or close to the surface of the site.  They carried it down to the river valley, where I can say from my old surface collection surveys, that they struck and worked that flint like never before nor since.

Link to a post about my old Thetford Forest Archaeology Survey.

Some of the worked flint that I recorded in the area.

Indeed, the excavation of one of the shafts at Grimes Graves revealed that the site was being used during the Middle Bronze Age, where a nearby settlement were depositing their rubbish into a midden in a disused shaft.  The archaeology of the midden suggested that the people living there then were most likely dairy cattle farmers.

That's Grimes Graves done.