Morphologic Diversity of Martian Ripples: Implications for Large-Ripple Formation
Large ripples with meter‐scale wavelengths are ubiquitous across Mars. Curiosity's traverse of the Bagnold Dune Field revealed a morphologic diversity of large Martian ripples that helps constrain their formative mechanism. Large ripples develop in isolated fields and on dunes. They form transversely and obliquely to longitudinally to the net sand‐flux direction in unimodally and bimodally distributed very fine to very coarse sand. They have either straight or sinuous crestlines. Inactive ripples are covered with dust, whereas migrating ripples are dust free. Here we present a unifying view of ripples that form in near‐bed sediment‐transport conditions (encompassing fluid‐drag and coarse‐grained ripples) to explain the range of large‐Martian‐ripple morphologies and expand the use of bedforms as environmental indicators.
© 2018 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Received 31 MAY 2018; Accepted 18 JUL 2018; Accepted article online 25 JUL 2018. This manuscript is dedicated to our dearly missed friend and colleague, Nathan Bridges. We thank Curiosity's Engineering and Science and Operations Teams and Malin Space Science Systems for their continuous dedication to obtaining the data used in this manuscript. We thank Ralph Lorenz and an anonymous reviewer for insightful reviews. We are grateful to Keaton Cheffer for generating DEMs of terrestrial current and coarse‐grained ripples. We thank Jaap Nienhuis and Taylor Perron for their generosity with their wave‐ripple data. MSL data are archived in the Planetary Data System (https://pds.nasa.gov/). M. G. A. L. was supported by the John Harvard Distinguished Science Fellowship Program within the FAS Division of Science of Harvard University.
Supplemental Material - grl57806-sup-0001-2018gl079029_si.docx