Ancient Sand Dune Research Journal Article

This study challenges the prevailing view that Wyoming's Middle Jurassic lower Sundance Formation solely originated from an open marine environment, presenting instead a variety of carbonate facies and significant eolian and reworked eolian deposits. Petrologic evidence points to large, cross-stratified sets of ooids formed in an eolian environment, triggered by the deflation of emergent ooid shoals after a fall in sea level. The discovery of these oolitic dunes marks the first documented occurrence of Mesozoic eolian carbonates in the Western Interior.