| I would advise reading the study as it provides much more information, including stratigraphic profiles of 4 different layers, maps/images of the trenches, borehole data, and various remote sensing surveys. Unit 1 (surface): 2,000-1000BC
Unit 2 : 6,000-5000 BC
Unit 3: 24,000-14,000BC
Unit 4: NO data Unit 2 is clearly artificial and represents a construction layer. It has pieces of cut columnar basalt aligned parallel to the ground -- which does not occur naturally, so it is undisputedly artificial. The soil filled on top of Unit 2 contains homogenous radiocarbon dates and no weathering indicating it was placed all at the same time. They unit 3 layer contains weathered rounded boulders stacked on top of each other -- this type of weathering normally occurs in a stream an their presence on top of a hill does seem to indicate they were placed there. They also seem to be placed into structures forming a wall. While it is less obviously artificial than unit 2 -- they still provide some compelling evidence that it is indeed artificial. They claim unit 4 is a natural andesite lava flow that has been "sculpted", but I don't see any evidence to back up that particular claim in the paper, unless i missed it. TLDR: they did exactly what you mentioned -- took samples from above / below / inside various construction layers, and the dates match the stratigraphic context.... It wasn't just 'scooped up in the vicinity of the pyramid. I agree given the nature of their claims, it would be ideal if they included another dating method like OSL to go along with the radiocarbon dates, but the radiocarbon dates themselves are not as half-hazard as you make them out to be. https://onlinelibrary.wiley.com/doi/10.1002/arp.1912 |
1. Soil is alive--it is constantly interacting with the atmosphere, if it is close enough to the surface, and the nutrients which seep through it and the various organic matter that lives inside it. You might be able to reliably date a peet bog or other undisturbed anoxic system, but packed soil in a tropical environment is a bit more suspect (no matter how buried). Otherwise the "date" of the soil is continuously evolving based on local conditions that are difficult to calibrate. That's why archeologists typically date things like the charred remains of a cooking fire, not soil.
2. Ok, assume that these dates are in any way meaningful. That still doesn't establish the age of the structure as claimed in the article. Surface dates are totally suspect for the reasons I gave above, but for the purpose of this point we can grant it. So Unit 1 provides only an unsurprising minimum age. The packed dirt in Unit 2 & 3 on the other hand is construction back-fill: the radiocarbon age of the packed soil is the average age of the soil they used in construction. But that soil was already old. Think about it this way: if you took that surface soil from Unit 1 and put it on top of your house porch, we'd now be able say your porch was constructed between 2,000-1000BC.
This article establishes that there were two construction phases, and that these phases were likely carried out at different times because different sources of back-fill soil were used. But that's it. The actual dates have no relation to the human activity.