Sedimentary Patterns in and around Craters from the Pinacate Volcanic Field, Sonora, Mexico: Some Comparisons with Mars

We present results of a reconnaissance study of sedimentary patterns around the Pinacate volcanic field and adjacent Sonora dunes. A cinder cone located in the dunes west of the Pinacates has acted as a sand-migration barrier and has formed a sand-free shadow downwind. This may be analogous to the manner in which dark streaks form downwind of Martian craters. Orbital and aerial photography of the Pinacates suggest that maars adjacent to the Sonora dunes are being infilled by dune sand. However, petrographic data suggest that erosion of friable tuffs and tuff breccias from crater walls is the dominant process filling in all of the craters.

The Martian situation is presently less complex than terrestrial examples, such as the Pinacates, since wind seems to be the dominant agent. Water erosion, however, may have been active in past history, and Martian craters may have been modified in a manner analogous to the Pinacate maars.