For years I have been puzzled by the enormous number of discoveries of the remnants of older civilizations deep underground. How did they get buried?Pompei I can understand. But most of the buried cities are far from volcanic activity. If there were only one or two non-volcanic cases, it would be a curiosity with several plausible theories. But city after city after city?
After living in Dakar for nearly six years, I begin, perhaps, to understand. Every year from December through June, harmattan [HAHR-mah-tahn] winds carry vast quantities of sandy dust from the Sahara, across West Africa, and out into the Atlantic (see photo--Dakar is the tiny, hooked peninsula near the bottom). Some days it's as thick as fog. At night, you can see it drift past the street lights.
At Dakar Academy, the maintenance staff frequently have to sweep the dust and sand off of our sidewalks, steps, and basketball court to keep them from being buried. But could this account for all of it? How high did the world's mountains used to be if cities are hidden beneath cities beneath cities beneath meters of sand? It baffles me.
(Satellite photo in public domain, from http://www.nasa.gov)
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