Discussion»Questions»Environment» Where did all the sand come from to form all deserts and how big a would a sand castle be if you used it all to make just one ?
The sand in deserts and other places indicates that that land was covered by a sea 10s or 100s of million years ago. Sand comes from the weathering of sandstone by wind and wave action on beaches. As the sea slowly subsides, it leaves in its absence sand. Paleontologists have found many fossilized sea creature skeletons in deserts.
There are two sources of sand, wind borne and water borne. Small rocks blown about by wind eventually shatter, making sand with sharp irregular edges. Small rocks blown about by water get rubbed down, making sand with smooth rounded edges.
A desert is defined by absence of animals, especially absence of people. It does not have to be dry or have sand. There are ice deserts here and there. An uninhabited island is called a desert island, and it might be quite lush because of volcanic soil, but no sand.
Not quite. Deserts don't support much life, and some are barren to all intents and purposes, but the actual definition is based on maximum annual mean precipitation, not the wildlife. The Antarctic is a desert, but it supports or at least hosts, life around its coast and in the surrounding sea.
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