Abstract by Jonathon Sevy
Field Evidence of Wind Pattern Effects on Yardang Morphology
Yardangs are wind-carved linear ridges that are found selectively on Earth and extensively on Mars. The history of the morphologic development of yardangs is not well known. In the Puna high plateau of Argentina there are ignimbrite deposits, many of which have been eroded into yardang fields, commonly called fleets. Yarding fleets are evenly spaced forms, facing into the wind, that resemble a fleet of boats sailing. A prominent fleet, known as Campo de las Piedras Pomez (CCP), was studied in the field in December 2018. CCP Yardangs have many wind indicators, known as dedos, throughout the fleet. Dedos extend finger-like toward the wind and have stronger lithic inclusions at the end, enabling them to act as wind indicators. Measuring direction and length of dedos through a transect of the CCP fleet it was found that dedos were facing both towards and away from the normal wind direction. The forward dedos averaged 4.0cm in length, while the reverse dedos were 3.3cm. From this it was determined that two wind directions, with one dominant, are present in the CCP.