> We know it's a hard unit of rock since it's a wave-eroded
> terrace that Khufu built his pyramid on. it's quite clear from
> the geology that it is a hard homogenous limestone, which Khufu
> took advantage of in the engennering of both the site and the
> masonry itself..... the Sphinx head was carved in a hard
> homogenous limestone too..... its should be quite clear the 4th
> dynasty ancient Egyptians has at least some understanding of
> the plateau's limestone lithology and its significance to their
> constructions at Giza.
> Do you know what geological mapping is..... when horizontal
> beds of rock are dipping the strike lines are drawn on
> topographical maps so the geologic structure can be predicted
> and mapped out with just some outcrop mapping being done..... a
> strike line follows a specific layer of rock along a given
> constant elevation. Folowiing the strike allows the 4th dynasty
> Egyptians to build their pyramids in the same unit of hard
> limestone without the need for advance surveying and drill core
> mapping to locate the desired limestone.
But surely you aren't suggesting that the only hard limestone at Giza was in a 750' strip the lenght of the three big pyramids. If this is the case that your point is made but my understanding is there are layers of soft and hard stone all over the plateau.
Just because the pyramids are the same height doesn't by itself show that it was only this specific line along which the pyramids might be built and that there were no outlying points that might accomodate a pyramid. Frankly I greatly doubt this is the case since the builders were well aware that there was a tremendous fissure just north of G1 which could severely impact the load bearing capacity of the cliff face yet they built here anyway. This could be the result of desiring to squeeze in a representation of the belt stars somewhere, anywhere, on the plateau.
Perhaps I'm still missing your point but I don't see the limiting factor in your words. I'm also wondering how the builders would have in depth informatrion about the plateau since it was presumably covered in sand. Vyse believed much of the plateau was stripped to bedrock but I think he probably meant the area in which they built rather than the entire region.
It stillisn't established fact that they'd not build on soft stone I believe. They built on worse and even soft stone has great ability to support weight.
My understanding is that geologists believe all limestone is deposited horizontally and you're suggesting that it's worn down dependent on its hardness so the strike has a similar and high hardness. Wouldn't a strike at higher altitude tend to have higher hardness yet? I just need a claim I can sink my teeth into as I can't envision a normal process that might leave a fortuitous band of harder stone along a line upon which they built but nowhere else but it seems this is what you're claiming.