The Great Pyramid of Giza is made from blocks of limestone quarried from the Giza plateau. The pyramid is composed up of about 200 layers, with individual blocks varying in thickness from 20 to 60 inches. How feasible would it be to identify which layers of limestone in the quarry were used in the various layers of the pyramid? For example, if a core sample were taken from the quarry could individual blocks from the pyramid be matched to a position along the core?
Theoretically? Maybe! Practically? No. Identifying the general quarry site by comparing lithology is often possible. It might be possible to identify a block as coming from a particular level in a quarry by detailed characterisation of micro-fossil assemblages. Geochemical analyses could assist. However the practical problems are almost certainly insurmountable:
- The limestone rocks used in the pyramids were deposited in a marine reef environment, so deposition rates could be quite high. This means that with small age differences between the top and bottom there may be negligible variation in the micro-fossils.
- The parts of the quarry from which rock was taken are, by definition, not there to be sampled. You would have to take your comparison core from the edge of the quarry and you would presumably be looking at the stratigraphy of the layer on the outside of the pyramid which may have come from the centre of the quarry. Reef limestones can change their characteristics significantly over short distances.
- The exposed limestone blocks will have been altered by weathering - so would probably need destructive sampling by coring to gather material for comparison.
- As an analogy, matching individual blocks to layers in a quarry would be like trying to match sawn wood to individual tree stumps in a forest. Conceptually possible, but would take an awful lot of work and even more luck.