Tuesday, June 30, 2015

Lakes become deserts: The story of Lake Chad

Lakes Become Deserts - The Story Of Lake Chad
Six thousand years ago, what is now Lake Chad in the country of the same name was the largest freshwater lake on Earth. What remains covers less than a hundredth of the same area. The paleolake Mega-Chad, as researchers have dubbed it, at one time more than filled the Bodélé depression, an area which now, six thousand years on, is the largest single source of airborne dust particles in the world.
We now know, thanks to examination of satellite imagery which has identified former shorelines and allowed researchers to date when the lakes had each of them, exactly when the paleolake began to decline, and we have been able to measure the rate. The process is fascinating – but the results are nothing short of amazing.
What’s amazing is that Lake Mega-Chad, having mostly dried up in a short burst (around six hundred years at the outside), was still enough to keep the depression dry ..

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