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Mars: Fourth Order Landscapes

Explore the different orders of relief on Mars, from the great crustal dichotomy to the secondary cratering issue and other features like folded mountains, lava tubes, and layered mensæ.

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Mars: Fourth Order Landscapes

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  1. Geography 441/541 S/16 Dr. Christine M. Rodrigue Mars: Fourth Order Landscapes C.M. Rodrigue, 2016 Geography, CSULB

  2. C.M. Rodrigue, 2016 Geography, CSULB Mars: Fourth Order Landscapes • The “Orders of Relief” for Martian Landscapes • The first order was the great crustal dichotomy and Tharsis: • Northern lowlands: ~ 1/3 • Southern highlands: ~2/3 • Tharsis Rise: ~1/4 • The second order was the large regional features: • Elysium Rise • The largest craters: Hellas, Argyre, Isidis, Utopia • Valles Marineris • The polar ice caps

  3. C.M. Rodrigue, 2016 Geography, CSULB Mars: Fourth Order Landscapes • The “Orders of Relief” for Martian Landscapes • The third order was the somewhat smaller major regions associated with the araeological eras: • In many ways, this is a cross-cutting category • It addresses the “geological column” or relative ages of all Martian landscapes in terms of the three regional units that gave the three-part sequences of Mars’ evolution their names: • The Noachian Era • The Hesperian Era • The Amazonian Era

  4. C.M. Rodrigue, 2016 Geography, CSULB Mars: Fourth Order Landscapes • The “Orders of Relief” for Martian Landscapes • The fourth order is “in order” now: • These are smaller features (a few kilometers to a few hundred km): • They are landscapes dominated by one or two processes • Fluvial valleys • Sapping alcoves • Outwash channels • Linear fossæ • Folded and faulted mountains of Thaumasia • Lava tubes • Layered mesas • Patterned ground • Wind abraded/etched landscapes • Dune fields • Evidence of mass wasting

  5. Mars: Fourth Order Landscapes Secondary cratering issue: (W.K. Hartmann painting http://psi.edu/hartmann/) C.M. Rodrigue, 2016 Geography, CSULB

  6. Mars: Fourth Order Landscapes • Secondary cratering issue: • Secondary cratering from a primary impact event can be hard to detect • odd-shaped craters are often described as secondaries • lower velocity impacts don't produce a symmetrical detonation C.M. Rodrigue, 2016 Geography, CSULB

  7. Mars: Fourth Order Landscapes • Secondary cratering issue: • Secondary cratering from a primary impact event can be hard to detect just from odd shapes • Plot complication: really low angle impacts, <15° , can also produce odd shapes, if rarely • Orchus Patera (340 x 140 km)? • Terra Sabæa near Huygens (80 x 20 km) • crater N of Acheron Fossæ C.M. Rodrigue, 2016 Geography, CSULB

  8. Mars: Fourth Order Landscapes • Secondary cratering issue: • Secondary cratering often produces linear chains of craters • THEMIS, +19 at 348E( Trouvelot Crater) • MOC, +16 at 325° (Margaritifer Terra) • MRO image of Candor Chasma wall with this weird chain cutting across at an angle to gravity • This can result from forces in the ejecta curtain organizing the debris into linear, unsorted rays, as seen (and preserved) on the moon C.M. Rodrigue, 2016 Geography, CSULB

  9. Mars: Fourth Order Landscapes • Secondary cratering issue: • My attempt to detect crater rays • 6th order nearest neighbors • calculated azimuths from each crater to its 6th order nearest neighbors • compensated for random “alignments” by counting craters at various standards of “alignment” and comparing the counts with the binomial distribution using a Chi-square goodness-of-fit test • a <15° departure of azimuths from that of the nearest neighbor pair was considered “aligned” C.M. Rodrigue, 2016 Geography, CSULB

  10. Mars: Fourth Order Landscapes • Secondary cratering issue: • My attempt to detect crater rays came out kinda groovy! C.M. Rodrigue, 2016 Geography, CSULB

  11. Mars: Fourth Order Landscapes • Secondary cratering issue: • Robbins and Head (2011) • mapped crater clusters • drew great circle routes • several great circles converged on Lyot Crater north of Arabia Terra C.M. Rodrigue, 2016 Geography, CSULB

  12. Mars: Fourth Order Landscapes • Folded and Faulted Mountains: • Grabens and folds • Thaumasia Highlands C.M. Rodrigue, 2016 Geography, CSULB

  13. Mars: Fourth Order Landscapes • Lava Tubes: • Lava flows under a crust, which may collapse • Pavonis • Check out catena C.M. Rodrigue, 2016 Geography, CSULB

  14. Mars: Fourth Order Landscapes • Lava Tubes: • Lava flows under a crust, which may collapse • Pavonis • Check out catena inside a graben or dike or lava tube C.M. Rodrigue, 2016 Geography, CSULB

  15. Mars: Fourth Order Landscapes • Layered Mensæ: • Resistant caprocks protect less resistant materials below • Artist: Marilynn Flynn www.tharsisartworks.com C.M. Rodrigue, 2016 Geography, CSULB

  16. Mars: Fourth Order Landscapes • Layered Mensæ: • Resistant caprocks protect less resistant materials below • Cydonia and the Face on Mars C.M. Rodrigue, 2016 Geography, CSULB

  17. Mars: Fourth Order Landscapes • Layered Mensæ: • Resistant caprocks protect less resistant materials below • Cydonia • Face with HRSC and MOC C.M. Rodrigue, 2016 Geography, CSULB

  18. Mars: Fourth Order Landscapes • Layered Mensæ: • Resistant caprocks protect less resistant materials below • The heart on Mars south polar region, ~255 m across C.M. Rodrigue, 2016 Geography, CSULB

  19. Mars: Fourth Order Landscapes • Faces of Other Species, too! • Flow of younger lava? • The Elephant on Mars • Thanks to Ms. Stoddard • Okay, not a mensa... C.M. Rodrigue, 2016 Geography, CSULB

  20. Mars: Fourth Order Landscapes • Yardangs: • Erosional æolian features • Classic sandblasting south of Olympus Mons taken by HRSC (Mars Express) near +6 by 220 • Earth grooved terrain/yardangs (military source: location unknown) C.M. Rodrigue, 2016 Geography, CSULB

  21. Mars: Fourth Order Landscapes • Yardangs: • Erosional æolian features • Interesting parallel between Earth yardangs (again some unspecified military source) and Mars yardangs and layered terrain • The Mars yardangs (top) are from Æolis Mensæ, just south of Elysium on the margins of the southern highlands C.M. Rodrigue, 2016 Geography, CSULB

  22. Mars: Fourth Order Landscapes • Dunes: • Depositional æolian features • Classic barchans in Nili Pateræ, a volcanic depression in Syrtis Major C.M. Rodrigue, 2016 Geography, CSULB

  23. Mars: Fourth Order Landscapes • Dunes: • Depositional æolian features • Dune field in Endurance Crater imaged by Opportunity • Closest ridges < ~1 m • Blue color in slacks between dune crests reflect hæmatite blueberries • Lighter dust accumulates more on the lip of the crests than on the flanks • Like Earth star dune fields, probably reflect an unpredictable wind regime, as seen in this mystery military image (below) C.M. Rodrigue, 2016 Geography, CSULB

  24. Mars: Fourth Order Landscapes • Dunes: • Depositional æolian features • Endurance Crater and its load of dunes C.M. Rodrigue, 2016 Geography, CSULB

  25. Mars: Fourth Order Landscapes • Patterned Ground: • Polygons and permafrost • Mars -72 at 29 (MOC) • Earth NW Territories, Canada, Sharon Johnson’s GeoImages, UC Berkeley • Stresses from: • Freeze-thaw of water • Expansion-contraction of other materials with temperature changes • Sorting of rock material in the polygon boundaries C.M. Rodrigue, 2016 Geography, CSULB

  26. Mars: Fourth Order Landscapes • Patterned Ground: • Polygons and permafrost • Close up of boulders and other larger clasts caught in the boundaries among polygons C.M. Rodrigue, 2016 Geography, CSULB

  27. Mars: Fourth Order Landscapes • Eskers: • Subglacial streams • Basal melt feeds streams • Stream beds later exposed as sinuous, gravelly ridges • Dorsa Argentea, north of the South Polar Ice Cap Basal Unit, southwest of Hellas, southeast of Argyre C.M. Rodrigue, 2016 Geography, CSULB

  28. Mars: Fourth Order Landscapes • Mass Wasting: • Landslides • Common on crater gully walls at a small scale • Very evident as a major mechanism for the expansion of Valles Marineris • Ganges Chasma • Noctis Labyrinthus C.M. Rodrigue, 2016 Geography, CSULB

  29. Mars: Fourth Order Landscapes • Mass Wasting: • Landslides • Common on crater gully walls at a small scale • Very evident as a major mechanism for the expansion of Valles Marineris • South Candor Chasma C.M. Rodrigue, 2016 Geography, CSULB

  30. Mars: Fourth Order Landscapes • Mass Wasting: • Chaos • Collapsed, jumbled terrain • May be source of massive outflows, possibly explosive if CO2 is involved • Aram Chaos, which seems to feed into Ares Vallis C.M. Rodrigue, 2016 Geography, CSULB

  31. Mars: Fourth Order Landscapes • Softened Craters: • Rims eroded • Burns Ridge (Opportunity) • Floors filled • Dust and ice (Mars Exp) C.M. Rodrigue, 2016 Geography, CSULB

  32. Mars: Fourth Order Landscapes • Softened Craters: • Rims eroded possibly by oceanic currents and processes before the northern lowlands dried out or were resurfaced with younger lavas • Ground penetrating radar (MARSIS on ESA Mars Express) C.M. Rodrigue, 2016 Geography, CSULB

  33. Mars: Fourth Order Landscapes • Softened Craters: • Floors filled • Water – alluvial fans in Eberswalde Crater (below) • Floors re-excavated by wind • Arabia Terra crater layers (to right) C.M. Rodrigue, 2016 Geography, CSULB

  34. Mars: Fourth Order Landscapes • Softened Craters: • Floors REALLY worked over • Arabia Terra Crater (MOC) C.M. Rodrigue, 2016 Geography, CSULB

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