Title: Modern Mars’ geomorphological activity, driven by wind, frost, and gravity Serina Diniega, Ali Bramson, Bonnie Buratti, Peter Buhler, Devon Burr, Matthew Chojnacki, Susan Conway, Colin Dundas, Candice Hansen, Alfred Mcewen, et al. To cite this version: Serina Diniega, Ali Bramson, Bonnie Buratti, Peter Buhler, Devon Burr, et al.. Title: Modern Mars’ geomorphological activity, driven by wind, frost, and gravity. Geomorphology, Elsevier, 2021, 380, pp.107627. 10.1016/j.geomorph.2021.107627. hal-03186543 HAL Id: hal-03186543 https://hal.archives-ouvertes.fr/hal-03186543 Submitted on 31 Mar 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. 1 Title: Modern Mars’ geomorphological activity, driven by wind, frost, and gravity 2 3 Authors: Serina Diniega1,*, Ali M. Bramson2, Bonnie Buratti1, Peter Buhler3, Devon M. Burr4, 4 Matthew Chojnacki3, Susan J. Conway5, Colin M. Dundas6, Candice J. Hansen3, Alfred S. 5 McEwen7, Mathieu G. A. Lapôtre8, Joseph Levy9, Lauren Mc Keown10, Sylvain Piqueux1, 6 Ganna Portyankina11, Christy Swann12, Timothy N. Titus6, Jacob M. Widmer 7 8 1Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, 9 CA 91009, USA 10 2 Department of Earth, Atmospheric, and Planetary Sciences, Purdue University, 550 Stadium 11 Mall Dr., West Lafayette, IN 47907, USA 12 3Planetary Science Institute, 1700 East Fort Lowell, Suite 106, Tucson, AZ 85719, USA 13 4Northern Arizona University, 537 S Beaver St, Flagstaff AZ 86011-6010, USA 14 5 CNRS UMR 6112 Laboratoire de Planétologie et Géodynamique, Université de Nantes, 44330 15 Nantes, France 16 6U.S. Geological Survey, Astrogeology Science Center, 2255 N. Gemini Drive, Flagstaff, AZ 17 86001, USA 18 7Lunar and Planetary Laboratory, University of Arizona, 1629 E University Blvd, Tucson, AZ 19 85721, USA 20 8Department of Geological Sciences, Stanford University, 450 Jane Stanford Way, Stanford, CA 21 94305, USA 22 9Colgate University, 13 Oak Dr., Hamilton, NY 13346, USA 23 10National History Museum, Cromwell Rd, South Kensington, London SW7 5BD, United 24 Kingdom 25 11Laboratory for Atmospheric and Space Physics, University of Colorado – Boulder, 1234 26 Innovation Dr., Boulder, CO 80303, USA 27 12U.S. Naval Research Laboratory, 4555 Overlook Ave. S.W., Washington, DC 20375, USA 28 *Correspondence author: [email protected], +1 818-393-1487. 29 30 © 2020. All rights reserved. 31 32 33 ABSTRACT 34 Extensive evidence of landform-scale martian geomorphic changes has been acquired in the 35 last decade, and the number and range of examples of surface activity have increased as more 36 high-resolution imagery has been acquired. Within the present-day Mars climate, wind and 37 frost/ice are the dominant drivers, resulting in large avalanches of material down icy, rocky, or 38 sandy slopes; sediment transport leading to many scales of aeolian bedforms and erosion; pits of 39 various forms and patterned ground; and substrate material carved out from under subliming ice 40 slabs. Due to the ability to collect correlated observations of surface activity and new landforms 41 with relevant environmental conditions with spacecraft on or around Mars, studies of martian 42 geomorphologic activity are uniquely positioned to directly test surface-atmosphere interaction 43 and landform formation/evolution models outside of Earth. In this paper, we outline currently 44 observed and interpreted surface activity occurring within the modern Mars environment, and tie 45 this activity to wind, seasonal surface CO2 frost/ice, sublimation of subsurface water ice, and/or 46 gravity drivers. Open questions regarding these processes are outlined, and then measurements 47 needed for answering these questions are identified. In the final sections, we discuss how many 48 of these martian processes and landforms may provide useful analogs for conditions and 49 processes active on other planetary surfaces, with an emphasis on those that stretch the bounds of 50 terrestrial-based models or that lack terrestrial analogs. In these ways, modern Mars presents a 51 natural and powerful comparative planetology base case for studies of Solar System surface 52 processes, beyond or instead of Earth. 53 54 KEY WORDS 55 Geomorphological activity; Mars; Comparative Planetology; Aeolian; Sublimation; Mass 56 wasting 57 58 HIGHLIGHTS 59 Mars’ surface is actively shaped in the present due to wind, frost/ice, and gravity. 60 Overlapping, high-resolution images from orbit are key for detection of activity. 61 In situ and orbital data are needed to fully characterize the active Mars processes. 62 Mars studies provide critical information about activity beyond that seen on Earth. 63 64 1 Introduction ............................................................................................................................. 5 65 1.1 Why focus on wind and sublimation as drivers for surface activity? .............................. 9 66 1.1.1 Other known present-day surface changes .................... Erreur ! Signet non défini. 67 1.1.2 Other potential/hypothesized causes of recent surface changes Erreur ! Signet non 68 défini. 69 1.2 Sources of seminal data .................................................................................................. 11 70 2 Wind-formed landforms........................................................................................................ 15 71 2.1 Depositional and Erosional Aeolian Landscapes: Materials and Landforms ................ 17 72 2.1.1 Wind-transported sediment grain properties ........................................................... 17 73 2.1.2 Wind-transported sediment composition ................................................................ 18 74 2.1.3 Bedforms: Types and Morphologies ....................................................................... 20 75 2.2 Aeolian Transport, Fluxes, and Erosion Rates ............................................................... 24 76 2.2.1 Thresholds of motion and transport hysteresis ....................................................... 25 77 2.2.2 Bedform migration and evolution ........................................................................... 29 78 2.2.3 Erosion Rates .......................................................................................................... 32 79 2.3 Open questions for martian aeolian landforms and sediment history ............................ 33 80 2.4 Open questions for the physics of aeolian processes ..................................................... 34 81 3 Seasonal Frost/Ice-formed Landforms .................................................................................. 35 82 3.1 Currently-formed surface frost/ice types on Mars ......................................................... 36 83 3.2 Seasonal sublimation triggered mass-wasting landforms .............................................. 38 84 3.2.1 Gullies ..................................................................................................................... 38 85 3.2.2 Dune alcoves ........................................................................................................... 41 86 3.3 Basal sublimation formed landforms ............................................................................. 42 87 3.3.1 Linear gullies .......................................................................................................... 42 88 3.3.2 Araneiforms ............................................................................................................ 43 89 3.4 Open questions for seasonal frost/ice and related landforms ......................................... 45 90 4 Long-term sublimation of ices .............................................................................................. 46 91 4.1 Polar surface landforms .................................................................................................. 47 92 4.1.1 South Polar Residual Cap ....................................................................................... 47 93 4.1.2 Massive CO2 Ice Deposit and its capping H2O ice layer ........................................ 50 94 4.1.3 North Polar Residual Cap H2O ice surface ............................................................. 50 95 4.2 Present/recent subsurface water ice................................................................................ 52 96 4.2.1 Present-day water ice stability ................................................................................ 52 97 4.2.2 Present-day water ice distribution ........................................................................... 53 98 4.3 Sublimation thermokarst ................................................................................................ 55 99 4.4 Patterned Ground............................................................................................................ 56 100 4.5 Open questions for long-term sublimation of ice ........................................................... 59 101 5