Geologic Features of Yardangs in Qaidam Basin and Analog Study with Mars

Qaidam Basin is the largest inland sedimentary basin in the north of the Tibet Plateau since the Cenozoic. According to remote sensing data, there are some mega uplifts lying NE-SW. These mega uplifts shows concentric elliptical shape in satellite images. Combining with field geological surveys, we believe these uplifts are mega yardangs. We have measured their length (l), width (w), and calculated the aspect ratio (R). The variation ranges of l, w and R are 14.18-67km, 5.5-16.5km and 2.32:1-6.09:1, with mean values are 31.3km, 8.86km and 3.56:1. In terms of R, 42.9% yardangs are 2:1 - 3:1, 23.8% yardangs are 3:1 - 4:1, 23.8% yardangs are 4:1 - 5:1, and the last are greater than 5:1. Their mean value is 3.59:1. The trend of mega yardangs are NW-SE. 45.5% of them are between 301°and 310°. Their mean trend value is 301.2°, which has a 10°angle different with local prevailing wind direction. Over the mega yardangs, there develops lots of small yardangs with various shapes. Their trends are similar with mega yardangs. We have collected some details data of morphology and samples, in order to find their relationship, and discuss the origin of yardangs and palaeoenvironment. Multisource remote sensing data indicate yardangs on Mars. We hope to do some analog study with mars. It may help us to better understanding the origin of yardangs and palaeoenvironment on mars.