Antecedent controls on the spatial organization of yardangs on the Puna Plateau, north‐western Argentina

Abstract

AbstractYardangs are streamlined ridges that form in arid environments on Earth and Mars through wind‐driven abrasion of consolidated substrates. Currently, there is limited consensus on the mechanisms that initiate and establish patterns of yardangs on the landscape. In this work, we examine the spatial organization of yardangs in the Campo de Piedra Pómez ignimbrite deposit of north‐western Argentina and identify evidence of antecedent controls on yardang patterns and formation. We mapped 14,826 yardangs in the region using a high‐resolution digital elevation model (DEM) and satellite imagery. We classified yardangs as points using a two‐stage decision rule based on morphology and spectral characteristics. Point pattern analysis shows that yardangs in the study area are not randomly distributed and commonly exhibit directional anisotropy in point pattern. The anisotropic pattern manifests as bands of closely‐spaced yardangs oriented transverse to the dominant northwesterly wind direction. We hypothesize that banding is controlled by pre‐existing antecedent topography in the bedrock, such as fumaroles or ridges associated with pyroclastic flow deposits. We present evidence from other locations on Earth and Mars to illustrate that the transverse banding is a common pattern in yardang landscapes.