Pacific Coastal and Marine Science Center
Bedform Sedimentology Site: “Bedforms and Cross-Bedding in Animation”
FIG. 48. Oblique dunes in a river meander, Muddy Creek, Wyoming, photographed by Bill Dietrich. The dunes, which are migrating from right to left, become oblique to transport because of cross-stream differences in the rate of advance of the dunes (Dietrich and Smith, 1984). Dietrich (pers. commun.) observed that the spurs migrated up point bar (away from the viewer) while the main bedforms migrated from right to left. Examples such as this demonstrate that bedforms and their superimposed topographic features can simultaneously migrate in different directions even in steady flows. The channel is approximately 5 m wide, and the largest dunes are 15 cm high.