There are some things in archaeology that fascinate me for no really logical reason: Vitrified forts are one of them.
Vitrified Fort at Dunnideer Scotland. Photo by Stu Smith
Vitrified forts are Iron Age hillforts that have been subjected to extreme heat, so hot in fact, that the surface of the stone turned to glass--vitrified. There are about 200 of these in the world, and archaeologists think some of these were set ablaze on purpose. Interesting, huh?
Comments
Re.vitrifiedforts – perhaps the use of the word “forts” is misleading to start with. This phenomenon appears on talayots, brochs, nuraghi, and Irish round towers.
One explanation I have heard is that these so far unexplained structures were designed as a form of “blast furnace” for the smelting of iron (or copper?)by the use of large quantities of brushwood. The presence of vitrification on the interior walls of these structures would appear to rule out one-off damage in a siege. The heating process, as mentioned on your site, would appear to have been continuous and repeated to achieve the effect, and would not have contributed to the strength of the structure.
It is possible that at a later stage they were adapted with windows, staircases, and chambers into living quarters.
To give an example of Irish round towers, popular belief is that they were constructed during the period of Norse raids to shelter monks and church plate. But it is said that they predate this period, and that there are indications that having fallen into disrepair they were restored in the Norse-raiding period as soirces of defence and temporary habitation.
Persian “fire towers” could well fit into this category also.
Comments would be welcome.
Desmond Johnston.
Having never heard of “vitrified forts” I am obviously no one to make any sort of definitive suggestion as to their use. But production of copper or iron produces large quantities of “slag” which should be everywhere around these structures if they had been used to produce metal. Simply checking around these structures with a $99 metal detector might be a good idea.
Why build a bast furnace on top of a hill? – it’s not logical.
The exact process of vitrification is not known. Experiments were carried out in the first half of the 20th century to replicate vitrification by fire and it proved impossible. The amount of wood required – and certainly not brushwood- would have been astronomical an unsustainable. And THEY were using railway sleepers .
To expand on Peter’s comment, one is led to think that they knew a technique that we somehow lost over time.
Facts like these intrigue me, as well!