Large wind ripples on Mars: A record of atmospheric evolution

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 (+10 others)
2016 Science  
Wind blowing over sand on Earth produces decimeter-wavelength ripples and hundred-meterto kilometer-wavelength dunes: bedforms of two distinct size modes. Observations from the Mars Science Laboratory Curiosity rover and the Mars Reconnaissance Orbiter reveal that Mars hosts a third stable wind-driven bedform, with meter-scale wavelengths. These bedforms are spatially uniform in size and typically have asymmetric profiles with angle-of-repose lee slopes and sinuous crest lines, making them
more » ... s, making them unlike terrestrial wind ripples. Rather, these structures resemble fluid-drag ripples, which on Earth include water-worked current ripples, but on Mars instead form by wind because of the higher kinematic viscosity of the low-density atmosphere. A reevaluation of the wind-deposited strata in the Burns formation (about 3.7 billion years old or younger) identifies potential wind-drag ripple stratification formed under a thin atmosphere.
doi:10.1126/science.aaf3206 pmid:27365444 fatcat:3dfpgiocozglvos5g7iwh33cre