3-RING CIRCUS IN MISSISSIPPI?

Three ring–shaped geomorphologic features are present in DeSoto, Tate, and Panola counties in extreme northwest Mississippi, one including Arkabutla Lake. These 15-20 km diameter features have a relief of 40 m in the Peoria Loess and are easily visible on satellite images. Others undoubtedly have seen at least Ring-1, the most obvious, but we know of no study of the features or of any observation of the ring morphology of the other two. What caused these features? We considered alternative explanations, 1) random topographic events, 2) Pre-Columbian Indian structures, 3) differential compaction over deep sinkholes, 4) differential compaction over deep plutons, 5) meteor impacts, and 6) differential compaction over buried oxbow lakes. The similar size and close proximity of the rings suggests a common cause however data beyond their morphology are limited and inconclusive. Differential compaction over buried meanders or oxbows in the gravel that underlies the loess is the most likely cause.