Soil is a mixture of minerals and organic material.
However much of archaeology isn't actually soil either, not in the true sense of it, but deposition of material in other ways other than soil which is generally 'created' in situ.
Soil does move under gravity but not very far and most certainly does not migrate 'en mass', even as wind blown, apart from the occasional mudslide.<
When you say that soil doesn't migrate 'en masse' do you count loess as soil or is it simply a mineral deposit which hisnt technically soil (I know its pargely just post glacial but its an example of large scale movements in the past). Similarly are sand blows soil or mineral (haivng worked on a site where the first bit of work was to remove a mettre or so of sterile sand from over the archaeology (a deposit which probably covered hundreds of hectares). There are also historical references to 'warping' using embankments to trap silt laden water to create new farmland, which could result in two or three feet of deposits - on the other hand this may not count as 'large scale' in global terms. Can you elaborate a bit on that please.
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