C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes Geography S/07 Dr. Christine M. Rodrigue

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The “Orders of Relief” for Martian Landscapes  The first order was the great crustal dichotomy:  Northern lowlands: ~ 1/3  Southern highlands: ~2/3  The second order is tonight’s focus:  Tharsis and Elysium rises  The largest craters: Hellas, Argyre, Isidis, Utopia  Valles Marineris  The polar ice caps

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Volcanic Rises  Tharsis

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Volcanic Rises  Tharsis  8,000 km across  Nearly 10 km thick  Single big hotspot plume?

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Volcanic Rises  Tharsis  Impact-generated?

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Volcanic Rises  Elysium  “Only” 6 km thick  “Only” 2,000 km across

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Volcanic Rises  Elysium  Recent volcanic activity: Hecates

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Volcanic Rises  Elysium  Glacial features on Hecates? Argued to be snow derived during an ice age produced by a greater obliquity

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  Huge: 30  of latitude by 50  of longitude  ~2,300 km across  ~8 km deep in local topography; 4 km below the geoid!

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  Depositional features: volcanic outflows and wrinkle ridges

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  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)

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  Erosional features (MGS MOC): boulder tracks down cliffs

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  Depositional features (MGS MOC): lacustrine, shoreline

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  Depositional features (MGS MOC): hunh? Water? Ice?

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Hellas Planitia  Depositional features (MGS MOC): dunes in southern Hellas

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Argyre Planitia  Hydraulic system

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Argyre Planitia  Wind deposition: dune (HRSC)  Wind erosion: dust devils (MOC)

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Argyre Planitia  Fluvial erosion: gullies in Galle  Complexity

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Isidis Planitia  Where Beagle was to land

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Isidis Planitia  Another complex history  1,500 km big impact

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Impact Basins  Utopia Planitia  Lava basin antipodal to Argyre  Viking 2 frost documentation

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  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

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Subsidiary chasmata

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Not your ordinary grand canyon (east end is actually higher than the middle)  Valles cut into layered material (sediments? lava?)  Extensional rifting (perhaps like East Africa?)  Pitting (suggests extension)  Alcoves (suggesting subsurface flow)  Landsliding widens the rifts  Massive jökulhlhaup-like outflows

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Looks like a canyon draining into Margaritifer and then Chryse  But look at the elevations of the central and eastern ends

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Layering in walls of Melas Chasma  Dunes covering floor

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Layering in walls of Hebes Chasma  And 100 in Candor Chasma below

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Extensional rifting in Tithonium Chasma  Pitting (suggests extension)

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Valles Marineris  Extensional rifting in Coprates Chasma and Catena  Pitting (suggests extension)

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Melas, Candor, Ophir Chasmata  Theatre-headed tributaries  Like Canyonlands, Utah  Sapping of groundwater

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Landslides  South Candor Chasma

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Jökulhlhaup?  On Earth, they are massive floods created when a glacier becomes a dam, as here at Russell Lake behind Hubbard Glacier in Alaska in 1986 and 2002, and the dam breaks

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Jökulhlhaup?  If Ares and Kasei valles were formed by outwash floods, here’s how they’d compare to various Earth measures!

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Great Canyons  Cerberus Fossæ  Seem tectonic: faulting  Lava flow from a fissure?

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Polar Ice Caps  North Polar Cap  Water ice cap  Seasonal CO 2 veneer

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Polar Ice Caps  North Polar Cap  Water ice cap  Seasonal CO 2 veneer

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Polar Ice Caps  South Polar Cap  CO 2  Water ice cap underneath?

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Polar Ice Caps  South Polar Cap  Layering  Drainage from beneath

C.M. Rodrigue, 2007 Geography, CSULB Mars: Second Order Landscapes  The Polar Ice Caps  South Polar Cap  Sublimation of CO 2 creates pits on surface?  Geyser-like jets of CO 2 in spring?