MORPHOMETRIC ANALYSIS OF YARDANGS SURROUNDING MEAD CRATER ON VENUS

Yardangs are relatively young (thousands of years time scale) aeolian erosional landforms that form due to a unidirectional prevailing wind carrying sand size particles that erode by abrading existing friable sediment material. Seen on Earth, Mars, Venus, and Titan - yardangs provide insight into past climate and landscape evolution. Insight into the Venus yardangs will provide further information on the landscape evolution processes at play around Mead and serve as an additional data set to the formation of aeolian features in the solar system. Two yardang fields on Venus had been identified, southeast and northeast of the 270 km diameter Mead crater. In this study we measured and performed morphometric analysis of the two previously identified yardang fields to infer the wind direction, initiating mechanism, age, lithology, and classification to further constrain the formational mechanisms and landscapes that produced these features. We utilized Venus Magellan FMAP Left-Looking and Stereo (Cycle 1 & 3) Look Global Mosaic (~75 m/pixel) Synthetic Aperture Radar (SAR) at S-Band (12.6 cm) wavelength data in ESRI ArcGIS software to map and measure the orientation, length/width of the yardang crests, and spacing of the yardang troughs. Preliminary data of a portion of the yardangs in the southeast field indicates a 40° northeast-southwest wind direction and an average length of ~19 km and width of ~0.5 km yielding a length:width ratio of 39:1 yielding a derived height range of 183-247 meters. These data suggest that the yardangs found in the southeast field are elongate ridge mega yardangs that are composed of competent lithologies such as indurated sediments or bedrock. The average spacing between the Mead yardangs is ~ 1km, yielding a width:spacing consistent with mature yardangs on Earth. The length:width and spacing requires an initiating mechanism with an original spacing on the order of 2 km that may be related to the underlying structures. Our morphometric analysis confirms the identification of yardangs and provides insight into the wind regime and supports the previous hypothesis that the yardang fields found around Mead crater are formed out of crater impact ejecta.