Mondo Knows Facts
Deserts have named surfaces, from sand to stone
Geographers separate sandy ergs, stony regs and rocky hamadas, and each forms differently An erg is a sea of sand, a reg is a gravel plain left after wind has blown the fine material away, and a hamada is bare rock. The words come from Arabic and were adopted by geologists mapping the Sahara. The surface type controls how fast the desert moves and how much dust it sends into the air. It sits in Mondo's world geography collection, one of 200 facts that each trace back to the reference below.
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Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.
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More facts like this
Spring tides have nothing to do with the seasonThe name comes from the old sense of springing upward, and the tides happen twice a monthThe Kalahari is not quite a true desertIt gets enough rain to grow grass and trees, so many classify it as dry savannaAntarctica is technically the largest desert on EarthAntarctica receives an average of less than 200 millimetres of precipitation each year along its coast and far less inland.The Atacama Desert is the driest non-polar desert on EarthSome weather stations in the Atacama Desert in northern Chile have never recorded a single drop of rainfall.The Sahara is the largest hot desert in the worldSpanning over nine million square kilometres, the Sahara covers much of North Africa.The Namib Desert is considered the oldest desert on EarthArid conditions have persisted in the Namib Desert along southwestern Africa coast for over 55 million years.
🗺️ World Geographyfact 124 of 200
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Tags: deserts, geology, vocabulary
Deserts have named surfaces, from sand to stone: the short answers
- Where does this come from, and can I check it?
- Geographers separate sandy ergs, stony regs and rocky hamadas, and each forms differently. The figure is taken from Smithsonian Ocean, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a world geography fact?
- Yes. It sits on the World Geography shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.