Stone enclosures that have come to become called 'Vitrified forts' are scattered about in a relatively small area of Scotland where they have been best documented. They are also found on a more limited scale in other parts of Western Europe. Tourists have been told that repeated lightning strikes are the cause, which is easily and repeatedly refuted.
Conventional Theories on Vitrified Forts of Scotland
No mortar, lime, cement of any kind can be found in these structures, they are all fused together by Vitrified stone. Vitrification is a process whereby stone is converted to glass via intense and sustained heat. Common fire is not thought to be able to achieve the vitrification found in these forts. The vitrification is not always easily identifiable. It is not solid blocks of glass, but appears more like indigenous light colored rocks embedded in an ebony asphalt.
In most cases huge blocks and stone boulders are fused with smaller rubble to form a hardened glassy mass. At times bubbles and small solidified eruptions and drips appear in the darker stones that serve as mortar.
In 1980 researchers led by archaeologist Ian Ralston attempted to duplicate the process by which ancient builders and warlords may have created these forts but failed. They piled stones upon one another and built a massive sustained bonfire but were only able to produce a few partially vitrified stones.
Previously, in the 1930s, researchers Wallace Thorneycroft and V. Gordon Childe conducted a similar experiment. slightly more successfully
The experimental wall was 6 ft. wide and 6 ft. high, with horizontal timbers interlaced with stone slabs. After ignition through brushwood fires around the wall face, the wall began to burn and after three hours it collapsed. The core of basalt rubble became red hot, probably reaching 800 to 1200 degrees C, and after excavation the bottom part of the rubble was found to be vitrified, with rock droplets and casts of timber preserved. The experiment proved that a timber-laced wall of this character could become vitrified through fire, but the explanation of the reasons for such widespread treatment of these Iron Age forts remains uncertain. [Proceedings of the Society of Antiquaries of Scotland ]
Neither of the experiments succeed in creating a vitrified fort, nor did either conduct extended experiments for long duration's that would have been necessary to create these enigmatic structures.
There are several alt-science theories that attempt to link ancient astronaut theories into these vitrified forts that are not without merit.
Ancient Atomic Warfare
One alternative theory is that ancient atomic blasts produced the vitrification. Fusion of stone and sand into glass has been observed at modern nuclear test sites and is also present at sites which it is theorized that societies / worlds before our own may have engaged in nuclear war. David Davneport and Ettore Vincenti - Atomic Destruction 2000 BC [*1] espouse a theory that a site in current day Pakistan known as Mohenjo Daro had been destroyed with a nuclear blast. Stratums of clay and green glass apparently melted by extreme high temperatures, and hardened afterwards. See: Nuclear War in Ancient India. The difference between the Scottish sites and the Pakistan site is radioactivity. There is no abnormal radioactive levels at the vitrified forts in Scotland, whereas the Mohenjo Daro site in Pakistan had a level of radiosctivity 50 times greater than normal. There are also chemicals produced in atomic blasts that are found at nuclear test sites but not at the Scotland vitirified fortresses. ANcient ATomic Warfare in Scotland is highly unlikely.
Ancient literature tells of 'Greek Fire', modern researchers do not know what this actually was that ancient Greeks hurled at their enemies vias catapult or rained down on invading armies scaling their fortress walls. The literature tells us it was substance that could not be extinquished and some accounts have it being capable of burning even under water. Its actual composition is believed to be phosphorous, pitch, sulfur and assorted flammable chemicals that could be gleaned from nature.
It is conceivable that some facsimile of Greek fire could have have been responsible for the vitrification. You can't sell many books with this theory so ancient astronaut theorists prefer to focus on ancient atomic weaponry instead.
Greek inventor Archimedes [circa 280 BC] is said to have built a death ray that could set ships ablaze and scorch enemy armies. Archimedes Death Ray is believed to have consisited of an enormous mirror and parabolic disc that focused sunlight on a Roman fleet setting fire to the ships in the harbor. One theory postulates that the ancient Scots may have used a similar device to vitrify their fortresses. It is a curious hypothesis with very little other than circumstantial evidence to back it up. Had ancient Celts had such a device it is very plausible that it could have fused the stones, did they ? God only knows. Speaking of the Divine, a fourth theory involves divine intervention which brings us back full circle to ancient astronaut theories.
Part Two Lugh's Spear