Fertilizing dust: from Sahara to Amazon forest

Short résumé from xkcd (http://what-if.xkcd.com/10/):

In Chad, on the southern outskirts of the Sahara, there’s valley called the Bodélé Depression. It was once a lakebed, and the dry dust in the valley floor is full of nutrient-rich matter from the microorganisms that lived there.

From October to March, winds coming in from the east are pinched between two mountain ranges. When the surface winds climb over 20 mph, they start picking up dust from the valley. This dust is blown westward, all the way across Africa, and out over the Atlantic.

That dirt—from one small valley in Chad—supplies over 50% of the nutrient-rich dust that helps fertilize the Amazon rainforest.

At least, according to that one study. But if it's right, it wouldn’t be a crazy anomaly. This kind of complexity is found everywhere. The basic building blocks of our world are crazy.