Mars: Second Order Landscapes

C.M. Rodrigue, 2015Geography, CSULB

Mars: Second Order Landscapes

Geography 441/541S/15

Dr. Christine M. Rodrigue



• The “Orders of Relief” for Martian Landscapes– The first order was the great crustal dichotomy and the

Tharsis bulge:_ Northern lowlands: ~ 1/3_ Southern highlands: ~2/3_ Tharsis: ~1/4



• The “Orders of Relief” for Martian Landscapes

– The second order is tonight’s focus: _ The largest craters: Hellas, Argyre, Isidis, Utopia_ Elysium volcanic rises_ Valles Marineris rifting and landslides_ Chryse Trough: possible fluvial drainage?_ Kasei Valles: jökulhlaup outflow_ Thaumasia block: mega-landslide?_ Syrtis Major: æolian process exposing basalt

_ The polar ice caps: CO2 and H

2O glaciation



• The Impact Basins– Hellas Planitia, Argyre Planitia, Isidis Planitia, Utopia Planitia



• The Great Impact Basins– Late Heavy Bombardment

_ The organization of the solar system ~ 4.6 Ga_ Accretion of dust and ices into clumps and planetesimals_ As they grew, interactions became more forceful_ Outer solar system gas giants gravitational interactions_ Uranus and Neptune pushed out by Jupiter and Saturn_ Smaller objects out there lobbed inward → LHB_ LHB peaked ~4 Ga, tapering off ~3.75 Ga_ This history dominated the Noachian period



• The Impact Basins– Hellas Planitia

• Huge: 30 of latitude by 50 of longitude• ~2,300 km across• ~8 km deep in local topography; 6.5 km below the geoid!



• The Impact Basins– Hellas Planitia– NASA/JPL/GSFC



• The Impact Basins– Hellas Planitia: Modifications after impact

• Depositional features: volcanic outflows and wrinkle ridges




• Erosional features (MGS MOC): – outflow channels Dao Vallis, Niger Vallis, and Harmakhis Vallis

along Hellas’ eastern wall– ~ 1 km deep and 8-40 km wide (must have been some outflow)




• Erosional features (MGS MOC): boulder tracks down cliffs




• Depositional features (MGS MOC): lacustrine, shoreline




• Depositional features (MGS MOC): Viscous flow? Water? Ice?



• The Impact Basins– Hellas Planitia

• Depositional features (MGS MOC): dunes in southeastern Hellas



• The Impact Basins– Argyre Planitia

• Part of hydraulic system?



• The Impact Basins– Argyre Planitia: Modifications

• Wind deposition: dune (HRSC)• Wind erosion: dust devils (MOC)




_ Fluvial erosion: gullies in Galle_ Complexity: impact, consolidation,

wind erosion




_ Radial and circumferential massifs_ Fluvial erosion: gullies on massif to northwest (HiRISE)



• The Impact Basins– Isidis Planitia

• Where Beagle was to land• 1500 km wide crater basin• Missing NE rim



• The Impact Basins– Isidis Planitia: Modifications

• Thermal inertia (map: Caprarelli & Orosei 2015)




• Dunes• Thumbprint terrain• Rootless cones?• Moraines and eskers?




• Thumbprint terrain (MOC)• Rootless cones?• Moraines and eskers?



• The Impact Basins– Utopia Planitia

_ Circular grabens, some of them double_ Draping of cover material (sediment?) over buried craters_ Folding and compaction into depressions creates grabens on

inner slopes of buried craters’ rims_ Sometimes shrinkage of cover material exerts tension

leading to grabens just beyond buried crater rim



• The Impact Basins– Utopia Planitia

• Lava basin antipodal to Argyre

• Viking 2 frost documentation

Mars: Second Order Landscapes

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