Linus Minimax

How Can We Determine the Age of Ancient Stone Walls? Officially? There's no straightforward way. At least not directly. After all, the stones themselves are supposedly millions of years old, right? And determining when they were carved is indeed impossible. There are, however, indirect methods routinely used to establish the age of ancient walls. Two particularly relevant ones are: Take organic material from beneath the wall and assume it has been there ever since the wall was built. Its radiocarbon age then provides a chronological constraint: the wall must be younger than the material beneath it. Determine the age of the mortar used as a binding material between the stones, using a technique called OSL dating. But here's the catch: megalithic walls are famous precisely for NOT having mortar or any other binding material between their stones. Uh-oh! Still, let's take a closer look at what the hell OSL dating actually is. Perhaps it can be useful even without mortar! OSL stands for Optically Stimulated Luminescence. The technique takes advantage of the fact that quartz grains mixed into mortar are essentially tiny geological clocks. And these particular clocks can be reset by exposure to light. Here's how it works: When quartz grains are exposed to daylight, their OSL signal is progressively erased. Under sufficiently strong sunlight, this process can happen remarkably quickly, sometimes in less than a minute. Once the sand is mixed into mortar and the mortar is incorporated into a wall, the grains are shielded from light. Their geological clocks start ticking again. Natural ionizing radiation from the surrounding materials and the environment gradually transfers energy to the quartz crystals. Some of the resulting electrons become trapped in defects within the crystal structure. The longer the grains remain buried in darkness, the more radiation dose they accumulate. And here's the clever part: the accumulated radiation dose can be measured. If we know how quickly the material has been receiving that dose, we can calculate how much time has passed since the grains were last exposed to sufficient light. And that's precisely what happens during OSL analysis! A sample is collected under carefully controlled dark conditions, so that the quartz grains' clocks aren't accidentally reset. It is then transported to a laboratory, where the quartz grains are stimulated with controlled light, typically blue or green. This releases the trapped electrons, allowing them to recombine and emit light. The resulting luminescence is measured. Sounds complicated? Because it is. But the basic principle is simple: the quartz grains in mortar can reveal when the sand was last exposed to daylight, provided the grains were sufficiently exposed during mortar preparation and subsequently shielded from light. Of course, not every grain necessarily gets fully reset. This is one of the major challenges in mortar dating, and specialized single-grain analysis can help overcome it. And here's where things get interesting! If a supposed natural rock is actually some kind of ancient concrete, then the quartz grains incorporated into that material could potentially be dated using exactly the same principle. The technique is NOT inherently restricted to mortar. In principle, it can be applied to other man-made composite materials containing suitable quartz grains, provided the grains were exposed to sufficient light before being incorporated into the material and the necessary dating conditions are met. TA-DAAAAA! So why isn't everybody doing this? Well, the explanation is simple. BECAUSE ARTIFICIAL STONES DON'T EXIST. PERIOD! That's humanity for you. Trapped in dogmas and outdated beliefs, we build artificial intelligence and send spacecraft into outer space. Absolutely incredible! ------------------------------------- By the way, am I really the only one noticing that while the stones in the wall are clearly full of holes and bubbles, the scattered loose stones lying next to it — which the builders apparently tossed into the tower later as rubble fill — are NOT porous at all? This photo was taken at Sillustani.