Large wind ripples on Mars: A record of atmospheric evolution

• DOI: 10.1126/science.aaf3206
• Publication Date: 2016-07-01T02:13:21Z
• Authors: M. G. A. Lapotre; R. C. Ewing; M. P. Lamb; W. W. Fischer; J. P. Grotzinger; D. M. Rubin; K. W. Lewis; M. J. Ballard; M. Day; S. Gupta; S. G. Banham; N. T. Bridges; D. J. Des Marais; A. A. Fraeman; J. A. Grant; K. E. Herkenhoff; D. W. Ming; M. A. Mischna; M. S. Rice; D. Y. Sumner; A. R. Vasavada; R. A. Yingst
• Keywords: Ripple marks; Orbiter; Bedform; Atmosphere of Mars

Wind blowing over sand on Earth produces decimeter-wavelength ripples and hundred-meter- to kilometer-wavelength dunes: bedforms of two distinct size modes. Observations from the Mars Science Laboratory Curiosity rover Reconnaissance Orbiter reveal that hosts a third stable wind-driven bedform, with meter-scale wavelengths. These are spatially uniform in typically have asymmetric profiles angle-of-repose lee slopes sinuous crest lines, making them unlike terrestrial wind ripples. Rather, these structures resemble fluid-drag ripples, which include water-worked current but instead form by because higher kinematic viscosity low-density atmosphere. A reevaluation wind-deposited strata Burns formation (about 3.7 billion years old or younger) identifies potential wind-drag ripple stratification formed under thin