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Geography 441/541 S/14 Dr. Christine M. Rodrigue. Mars: Second Order Landscapes. 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
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Geography 441/541 S/14 Dr. Christine M. Rodrigue Mars: Second Order Landscapes C.M. Rodrigue, 2014 Geography, CSULB
C.M. Rodrigue, 2014 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
Mars: Second Order Landscapes • The Volcanic Rises • Tharsis C.M. Rodrigue, 2014 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, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Volcanic Rises • Tharsis • Impact-generated? C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Volcanic Rises • Elysium • “Only” 6 km thick • “Only” 2,000 km across C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Volcanic Rises • Elysium • Recent volcanic activity: Hecates C.M. Rodrigue, 2014 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, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Valles Marineris C.M. Rodrigue, 2014 Geography, CSULB
C.M. Rodrigue, 2014 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
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, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Valles Marineris • Layering in walls of Melas Chasma • Dunes covering floor C.M. Rodrigue, 2014 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, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Valles Marineris • Extensional rifting in Tithonium Chasma • Pitting (suggests extension) C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Valles Marineris • Extensional rifting in Coprates Chasma and Catena • Pitting (suggests extension) C.M. Rodrigue, 2014 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, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Landslides • South Candor Chasma C.M. Rodrigue, 2014 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, 2014 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, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Valles Marineris • Subsidiary chasmata C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Great Canyons • Cerberus Fossæ • Seem tectonic: faulting • Lava flow from a fissure? C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The “Blue Scorpion” of Syrtis Major • AKA Hourglass Sea • First recorded feature • Sketch map by Christiaan Huygens (1659) • Arguably recorded earlier by Francisco Fontana (1636) • Giovanni Schiaparelli showed it in his map of 1888 C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The “Blue Scorpion” of Syrtis Major • Low relief volcanic shield • Hesperian age • Low albedo due to wind • Surface is basalt • Interesting effect downwind of high rim craters: windshadow and dust deposition creates bright streaks C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Polar Ice Caps • North Polar Cap • Water ice cap • Seasonal CO2 veneer C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Polar Ice Caps • North Polar Cap • Water ice cap • Seasonal CO2 veneer C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Polar Ice Caps • South Polar Cap • CO2 • Water ice cap underneath? • Yes, ~ 8m down C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Polar Ice Caps • South Polar Cap • Layering • Drainage from beneath C.M. Rodrigue, 2014 Geography, CSULB
Mars: Second Order Landscapes • The Polar Ice Caps • South Polar Cap • Sublimation of CO2 creates pits on surface? • Geyser-like jets of CO2 in spring? C.M. Rodrigue, 2014 Geography, CSULB