Inner planets

  • Perspective
    | Open Access

    Vast, ancient impact basins scattered mantle materials across the lunar surface. We review lunar evolution models to identify candidate mantle lithologies, then assess orbital observations to evalutae the current distribution of these materials and implications for fundamental planetary processes.

    • Daniel P. Moriarty III
    • , Nick Dygert
    •  & Noah E. Petro
  • Article
    | Open Access

    The authors report in-situ formation of jarosite witin the Talos Dome ice core (East Antarctica) and show that this ferric-potassium sulfate mineral is present in ice deeper than 1000 meters and progressively increases with depth. This has implications for the presence and formation mechanisms of jarosite observed on Mars.

    • Giovanni Baccolo
    • , Barbara Delmonte
    •  & Massimo Frezzotti
  • Article
    | Open Access

    Applying high-pressure and -temperature experiments, the authors here measure sound velocities in various liquid Fe-S alloys under conditions expected for the upper Martian core. The results together with future InSight mission data will help to understand whether the Martian core is molten Fe-S.

    • Keisuke Nishida
    • , Yuki Shibazaki
    •  & Kei Hirose
  • Article
    | Open Access

    Using high-resolution orbital imagery of the Martian surface, the authors Salese et al. here describe the first discovered stratigraphic product of multiple extensive fluvial-channel belts in an exposed vertical section at Izola Mensa in the northwestern rim of the Hellas Basin.

    • Francesco Salese
    • , William J. McMahon
    •  & Maarten G. Kleinhans
  • Article
    | Open Access

    Applying first-principles molecular dynamic simulations and thermodynamic modelling, the authors suggest a vertical oxygen fugacity gradient in magma oceans of Earth, Mars, and the Moon. Consequently, the study proposes larger planets like Earth to have stronger oxidized upper mantles than smaller bodies such as Mars or the Moon.

    • Jie Deng
    • , Zhixue Du
    •  & Kanani K. M. Lee
  • Article
    | Open Access

    Telecommunication, navigation and remote sensing services are highly dependent on how well satellites provide global coverage. Here the authors show a pair of four-satellite low-cost longer-life constellations that provide nearly continuous global coverage to support Earth observation.

    • Lake A. Singh
    • , William R. Whittecar
    •  & Patrick M. Reed
  • Article
    | Open Access

    Due to active geological resurfacing, the record of large impact basins (e.g. in Chryse Planitia) on Mars seems to be widely absent. Based on high-quality global datasets, the authors here propose a buried impact basin, covered by up to 1 km of sediments or lava flows after its formation more than 4 billion years ago.

    • Lu Pan
    • , Cathy Quantin-Nataf
    •  & Chloé Michaut
  • Article
    | Open Access

    A planetary-scale streak structure in the Venusian lower-cloud layer was observed by the Akatsuki orbiter. Here the authors present numerical simulations that reproduce such structure and reveal that a low-stability layer, which induces baroclinic disturbances, is essential for its formation.

    • Hiroki Kashimura
    • , Norihiko Sugimoto
    •  & Yoshi-Yuki Hayashi
  • Article
    | Open Access

    A unified model for the formation of martian rock types is required to understand Mars’s formation and evolution. Here the authors show that nakhlite and chassignite meteorites originate from melting of metasomatized depleted mantle lithosphere, whereas shergottite melts originate from deep plume sources.

    • James M. D. Day
    • , Kimberly T. Tait
    •  & Clive R. Neal
  • Article
    | Open Access

    Mantle partial melting produced the volcanic crust of Mercury. Here, the authors numerically model the formation of post-impact melt sheets and find that mantle convection was weak at around 3.7–3.8 Ga and that the melt sheets of Caloris and Rembrandt may contain partial melting of pristine mantle material.

    • Sebastiano Padovan
    • , Nicola Tosi
    •  & Thomas Ruedas
  • Article
    | Open Access

    In the Gale Crater on Mars, organic matter has been detected, but in much lower concentrations than expected. Here, the authors conduct clay mineral synthesis experiments which suggest that clay minerals may rapidly form under oxidized conditions and thus explain the low organic concentrations in Gale Crater.

    • Seth R. Gainey
    • , Elisabeth M. Hausrath
    •  & Courtney L. Bartlett
  • Article
    | Open Access

    Mars hosts the solar system’s largest volcanoes, but their formation rates remain poorly constrained. Here, the authors have measured the crystallization and ejection ages of meteorites from a Martian volcano and find that its growth rate was much slower than analogous volcanoes on Earth.

    • Benjamin E. Cohen
    • , Darren F. Mark
    •  & Caroline L. Smith
  • Article
    | Open Access

    The origin of the numerous linear grooves and craters that litter the Martian moon Phobos' surface remains enigmatic. Here, by modelling low-velocity escaping ejecta from impacts to Phobos, the authors show that several of these chains can be explained by reimpacting sesquinary ejecta shortly after ejection.

    • M. Nayak
    •  & E. Asphaug
  • Article
    | Open Access

    The discovery of rounded pebbles by Curiosity suggests sustained fluvial activity existed on Mars, but interpretations have been qualitative. Here, the authors show that transport distance can be calculated on the basis of pebble shape alone, suggesting they travelled 10 s of km by bed-load transport.

    • Tímea Szabó
    • , Gábor Domokos
    •  & Douglas J. Jerolmack
  • Article |

    Although observations of volcanic deposits on Mars are more accessible than ever, constraining Martian eruption styles remains a challenge. Here, the authors show that volcanic eruption style can be characterized through X-ray diffraction analysis of groundmass crystallinity in basaltic volcanic deposits.

    • Kellie T. Wall
    • , Michael C. Rowe
    •  & Jennifer D. Eccles
  • Article |

    Recently, the NASA MESSENGER mission reported signatures of Kelvin–Helmholtz instabilities in the magnetic environment of Mercury. Using global hybrid kinetic simulations, Paral and Rankin reproduce these observations, revealing a dawn–dusk asymmetry in the instability.

    • Jan Paral
    •  & Robert Rankin