Dear Ian

I have just read George Forrest's email to you regarding tectonics and Kate Spence's work. He asks if he's missing something, and he is. Colin Reader and I have done some checking and it appears that continental drift can be ruled out as having any significant effect on pyramid alignments.

In order for drift to have changed the alignments relative to the cardinal directions, the plate the Giza Plateau is part of (African) would have needed to not only have moved, but rotated relative to the Earth's axis of rotation as well. From the best geotechnical data available, this isn't happening very fast - Colin has investigated this and finds it to be something of the order of 1/1000 of an arc second over the last 4500 years (see The PALEOMAP Project and The NUVEL 1 Relative Plate Motion Calculator).

Of course Colin's analysis is for the African plate as a whole. There are many places on Earth where bits and pieces of continents are moving differently than the overall drift. Best example I can think of is in North America, where that portion which makes up northern Nevada and California, Oregon and Washington has rotated almost 60 degrees relative to the rest of the plate over the last 55 million years or so. Since Giza sits adjacent to the Red Sea Rift Zone, it would not surprise me at all if some odd mini-crustal things are happening there as well. So I guess the distinction we need to make is between continental drift and crustal deformation. From what I've been able to find out, no one who has published on the Web has looked at NE Africa carefully enough to make this call. Darn it, the devil is ALWAYS in the details!

As to the other ideas George throws out, none of them hold water (so to speak). Giza is a long way from anywhere a tsunami could have had any effect - not that they are capable of moving anything as big as the Plateau in the first place. And he has a factual error in his message as well. Sea level has RISEN at least two meters over the last 5000 years, not fallen.

Alex Bourdeau