Dust plays a small role in our everyday lives, often in the form of a minor inconvenience or mess. However, for ancient humans, dust was critical to the formation of civilization. Over fifty thousand years ago, the Levant, a region situated on the Mediterranean Sea’s fertile crescent, acted as an important passageway point for migration between Northern Africa and Eurasia. Early humans relied on the rich soils of this region to support agricultural productivity. A recent study published in Geology now reveals the importance of dust to this agricultural establishment.
Dr. Rivka Amit and her team at the Geological Survey of Israel discovered the critical role dust deposition played in forming the thick soils that make up the Levant. For Mediterranean soils, a high erosion rate, i.e. how quickly rock weathers, is often necessary to form agriculturally rich soil plots. However, on its own, a high erosion rate was not enough to explain the thickness seen in this region. Amit and her colleagues discovered the cause after tracing the soil back to its original source: the Negev Desert. Specifically, it was the deposition of coarse dust grains from the dune fields of this desert that established such thick soil.
These large fluxes of coarse gains have not always been depositing to the Levant. When the researchers examined the deeper soil profile, they found a past of very thin soils, which would not have supported the agricultural productivity and survival of ancient human civilizations. It was only when wind patterns changed around 200,000 years age and the Negev Desert dunes were created that enough coarse grains could be deposited to create the thicker soils needed. These underlying geological forces played a substantial part in human migration out of Africa and across the Eurasian continent. Without the contributions from dust particles, brought over by wind, the entire course of humanity could have played out very differently.
Dr. Rivka Amit is a senior researcher of geological hazard for the Geological Survey of Israel. Her primary research interests are in geomorphology, quaternary geology, soil stratigraphy, plaeoseismology, and sedimentology.
Managing Correspondent: Samantha Tracy
Press Article: “Dust may have controlled ancient human civilization”
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