The fairy circles (circular barren patches) of the Namib Desert - What do we know about their cause 50 years after their first description?

Barren ground depressions, natural H2 and orogenic gold deposits: Spatial link and geochemical model

“…Such geomorphological features had not been linked to hydrogen emission until now. However, they recall by their size, density and shape, the fairy circles described in Namibia, South Africa, Angola and Australia (Getzin et al, 2021a;Meyer et al, 2021). Getzin et al (2021b) proposed three criteria to define fairy circles: the absence of vegetation, their occurrence in semi-arid regions and their organization into periodic patterns.…”

“…The orange and yellow triangles refer to locations where small (< 20 m wide) barren white spots are observed near gold deposits and carbonatites, respectively. The pink dots indicate known location of fairy circles (Getzin et al, 2016;Meyer et al, 2021).…”

“…Ground depressions containing H 2 have sometimes been named "fairy circles" by previous authors (Prinzhofer et al, 2019;Myagkiy et al, 2020b;Moretti et al, 2021;Frery et al, 2021). The genuine fairy circles found in Namibia, Angola and Australia are characterized by an occurrence in semi-arid regions, an absence of vegetation in their center, a circular shape, a small size ( < 20 m in diameter), and an organization in spatially periodic patterns (Meyer et al, 2021;Getzin et al, 2021b). Based on these properties, Getzin et al (2021b) recently pointed out that the name "fairy circles" should not be used for previously described ground depressions emitting H 2 due to their large size (up to several hundreds of meters) and to their disordered spatial distribution.…”

“…Nevertheless, the morphology and the barren soil in the center of both ground depressions and fairy circles suggest that they could form by the same process. The formation of fairy circles sensu stricto is generally attributed to ecological processes including termite activity and self-organization due to plant competition in a water-limited ecosystem (Meyer et al, 2021). Microseepage of gas (carbon monoxide) and hydrocarbons has also been measured in fairy circles, suggesting a geochemical origin (Naudé et al, 2011).…”

First Peoples’ knowledge leads scientists to reveal ‘fairy circles’ and termite linyji are linked in Australia

“…Tinley (1971) was the first scientist to write about the bare patches in Namibia. The term was then used in a scientific paper in 1994, but its definition and attributed causes remain contested 32 .…”