Abstract

Planetary wind streaks are common aeolian features that have been studied primarily on Mars, Venus and Earth for several decades. They appear in imagery as distinctive albedo patterns on planetary surfaces. Most studies used remote sensing observations as the key means of investigation and lacked field validation. Although wind streaks are known on Earth, they have barley been studied in the field, with merely six published field investigations in the last forty years that were identified. This study presents an in-depth field study at eight sites in the Mojave and Atacama deserts with wind streaks conducted during three campaigns. The purpose was to investigate the spatial variability of surface properties responsible for the wind streak visibility in remotely sensed imagery in a way that will help better understand streaks on other planets. Data obtained from the surface includes field and satellite spectroscopy, and sampling for x-ray diffraction and particle size distribution analyses. The results show that for each wind streak, variations in the same surface settings lead to different appearances, even if the mineralogical and lithological settings of the sites are similar. Generally, wind streaks on Earth are composed of fine to medium sand particles, comparable to grain sizes observed in dark Martian wind streaks. The lack of finer fractions indicates on an active erosional environment. This supports previous studies suggesting that Earth wind streaks are likely to be presently active and are aligned in accordance to the modern prevailing winds.