A.H. Knoll R. E. Arvidson James W. Ashley J.F. Bell III W. M. Calvin P. R. Christensen B. C. Clark B. A. Cohen P.A. De Souza Jr. L. Edgar W. H. Farrand I. Fleischer Ralf Gellert M.P. Golombek J. Grant J. Grotzinger A. Hayes K. E. Herkenhoff J. R. Johnson B. Jolliff G. Klingelhofer A. Knudson R. Li T.J. McCoy S. M. McLennan D. W. Ming D. W. Mittlefehldt R.V. Morris J. W. Rice Jr. C. Schroder R.J. Sullivan A. Yen R.A. Yingst S. W. Squyres 2009 The Mars rover Opportunity has explored Victoria crater, a ???750-meter eroded impact crater formed in sulfate-rich sedimentary rocks. Impact-related stratigraphy is preserved in the crater walls, and meteoritic debris is present near the crater rim. The size of hematite-rich concretions decreases up-section, documenting variation in the intensity of groundwater processes. Layering in the crater walls preserves evidence of ancient wind-blown dunes. Compositional variations with depth mimic those ???6 kilometers to the north and demonstrate that water-induced alteration at Meridiani Planum was regional in scope. application/pdf 10.1126/science.1170355 en Exploration of Victoria crater by the mars rover opportunity article