- European Space Agency, Noodwijk, Netherlands (elena.favaro@esa.int)
Every Grain Tells a Story: Deciphering Planetary Processes Through Sediment Transport on Earth, Mars, and Beyond
Introduction
Across the solar system, granular material - from microns to meters across - moves through air, water, and materials in between. This fluid-, gravity-, impact-, and sublimation/volatile-driven transport represents fundamental geological and geomorphological processes responsible for shaping surfaces of rocky and icy worlds across our solar system. And yet, despite the importance and ubiquity of sediment transport, our ability to observe, predict, and model these processes beyond Earth remains difficult.
Mars represents a natural laboratory on which we can refine terrestrial-derived and validated sediment transport equations, assumptions, and limitations with orbital images and in situ observations. However, the translation from Earth to Mars (indeed, any other solar system body) is not straightforward. Differences in atmospheric density, gravity, grain properties, and the absence of liquid water under present conditions mean that terrestrial models cannot be applied uncritically.
Scales of the Problem
Mars Global circulation models (MGCMs), mesoscale models, and large eddy simulations (LES) of near-surface winds and vorticity are approximated from our ‘best guess’ of atmospheric dynamics on Mars, which take into account, among many factors, past and present-day obliquity, orbital eccentricity, turbulence, ice reserves, dust loading, atmospheric density, gravity, and the precession of perihelion. We apply these models to synoptic, regional, local, and site-specific locations which, in turn, have their own landscape-level factors (such as topography and sediment supply) to consider [1]. Determining how these elements interact requires a careful consideration and balance between evidence, hypotheses, and speculation.
The surface of Mars preserves extensive evidence of aeolian modification across a wide range of spatial and temporal scales. Dust and granular features such as centimetre-scale ripples [2,3], meter- to decimetre-scale transverse aeolian ridges [4], decimetre- to kilometre-scale dust devils (whose columns can extend for kilometres into the atmosphere) [5], and kilometre-scale dunes, dune fields, and unconsolidated sand-sheets [1,6-7], speak to the active and/or contemporary (geologically-speaking) sediment transport shaping Mars on observable timescales. Consolidated features such as centimetre- to meter-scale ventifacts and stratigraphic exposures [8-9], meter- to decimetre-scale periodic bedrock ridges [10-11], and kilometre-scale yardangs [12] speak to old much older (geologically speaking), perhaps inactive, or otherwise static features whose morphology and orientation speak to much older climatic regimes. Taken together, Martian features encode information about contemporary and palaeoclimatic (wind) regimes, erosion rates, and sediment production, availability, and flux [13-14]. Reading these signals is therefore critical to understanding the Martian environment across spatial and temporal scales, and for the safe and efficient operation of surface missions.
Decoding Transport Signals in Practice
In this presentation, I will draw on decades’ worth of sediment transport work on Mars, with a special emphasis on recent work at Oxia Planum, the 2030 landing site of the ExoMars Rosalind Franklin rover. I will highlight the work undertaken to piece together the complicated surficial and climatic history of the landing site, and Mars in general. I will discuss our recent morphometric work on TARs [15-16] , PBRs [11,15-16] , dust devils [15,17], and wind streaks [18] and highlight the MGCM, mesoscale, and LES modelling results that continually challenge our interpretations, not only of the landscape, but of our modelling assumptions as well.
I will also draw on fieldwork from the Puna Plateau of Northwestern Argentina [19] (a high-altitude, hyper-arid, vegetation-free landscape, with strong diurnal temperature swings), Lake Askja, Iceland [20] (a basaltic landscape at the foot of an active volcano in the central highlands in Vatnajökull National Park), and Scoraig, Scotland [21] (a remote site hosting an exceptionally preserved deltaic succession that coincided with the emergence of life on Earth) to review the ways in which we apply terrestrial understanding to Martian landscapes.
Beyond Mars
Atmospheric modelling, interpretation of orbital images and in situ observations, and leveraging terrestrial analogues, all illustrate a broader principle: sediment transport, and the features created, are archives of environmental conditions in absence of large-scale site-specific atmospheric, climatic, geologic, and geomorphologic data on Mars. Interpreting these archives requires an understanding of the full chain of processes, from atmospheric forcing to grain-scale interaction. On Earth, we can observe each link in that chain. On Mars, we often only observe endpoints or snapshots of processes; intermediate conditions must be inferred. As we extend our sights elsewhere in the solar system - from the dense winds of Venus, to the methane rivers of Titan, or to the electrostatically charged surfaces of airless bodies - even those endpoints become difficult to decipher. Continuing work on Mars, informed by research conducted on Earth, provides us with a dynamic template on how to approach sediment transport studies on other bodies. Fundamentally, we all want to know the same thing: what moved this material, and what does its surface expression tell us about the world it sits on?
[1] Chojnacki et al., 2019. Geology, 47(5); [2] Lapotre et al., 2019. Science, 353(6294); [3] Lapotre et al., 2018. GRL (45)19; [4] Balme et al., 2008. Geomorphology, 101(4); [5] Reiss et al., 2017. Dust Devils; [6] Thomas et al., 1981. Icarus (45)1; [7] Runyon et al., 2017. EPSL 457; [8] Herkenhoff et al., 2023. JGR: P, 128(3); [9] Banham et al., 2026. Geology; [10] Montgomery et al., 2012. JGR 117(E3); [11] Favaro et al., 2024. EPSL 626; [12] Mandt et al., 2008. JGR 113; [13] Davis et al., 2020. Earth and Space Sci. 7; [14] Swann et al., 2020. GRL 47(3); [15] Favaro et al., 2021. JGR: P, 126(4); [16] Silvestro et al., 2021. GRL, 48(4); [17] Grindrod et al., 2025. EPSC-DPS 2025 Meeting; [18] Silvestro et al., 2026. EGU26-11725; [19] Favaro et al., 2020. Icarus, 113765; [20] Favaro et al., 2023. 54th LPSC; [21] Banham et al., 2023. 54th LPSC.
How to cite: Favaro, E.: Every Grain Tells a Story: Deciphering Planetary Processes Through Sediment Transport on Earth, Mars, and Beyond , Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-655, https://doi.org/10.5194/epsc2026-655, 2026.
