Africa’s Mystery Circles

In a 1,500-mile [2,000 km] swath along the western edge of the Namib Desert in southwestern Africa, patches of barren, sandy soil 6 to 30 feet [2 m to 10 m] in diameter dot the landscape. Each patch is girded with a ring of tall grass. To some visitors the rings look like terrestrial chicken pox or splash marks made by giant raindrops. Local tradition has it that these circles possess magical powers. Some tribes believe that each circle surrounds the grave of a Bushman who died in one of the many conflicts between Bushmen and colonialists over the centuries.

Scientists too have long sought to explain the rings. In 1978, assuming that over time the circles would shift position, researchers marked the centers of some with metal stakes. Twenty-two years later, the circles had not moved. There have been abundant theories on the origin of the circles, reports London’s newspaper The Daily Telegraph, including “termite activity, poisoning from toxic indigenous plants, contamination from radioactive minerals and even ostrich dust baths.” Professor of botany Gretel van Rooyen of the University of Pretoria, South Africa, led a recent research effort to try to understand the circles. She reports: “One by one we tested the theories and one by one they were disproved.”

Perhaps significantly, the researchers did find that grass withered when planted in soil taken from inside the circles. But it grew well in soil taken from the grassy rings, confirming that there is a difference between the soil in the two areas. Although initial soil testing failed to provide any explanation, Van Rooyen hopes that analysis using a mass spectrometer will turn up further information. She wonders if there are toxic elements in the soil of the circles. “But even if we find them,” Van Rooyen says in New Scientist, “how they came to be there is the next problem.” For now, then, the circles remain one of earth’s many fascinating mysteries.

[Picture Credit Line on page 27]

Courtesy of Austin Stevens