Mars: Fifth Order Landscapes

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

2. C.M. Rodrigue, 2016 Geography, CSULB Mars: Fifth 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: Fifth 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 Period • The Hesperian Period • The Amazonian Period

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

5. C.M. Rodrigue, 2016 Geography, CSULB Mars: Fifth Order Landscapes • The “Orders of Relief” for Martian Landscapes • The fifth order is the final scale in the martian orders of relief: • These are very small features, < 1 cm up to several m in size • This is the scale of things observed from landers and rovers or small sections of high resolution orbiter sensors (e.g., HiRISE, MOC, HRSC) • Boulders and rocks • Frost deposits • Sand and dust streaks • Dust devil track • New gully deposits • New seasonal damp (?) streaks

6. Mars: Fifth Order Landscapes • Individual rocks and boulders, often named: • Pathfinder lander images Sojourner rover • Yogi is large rock: low quartz content, basalt • Barnacle Bill to left: andesitic, with more quartz C.M. Rodrigue, 2016 Geography, CSULB

7. Mars: Fifth Order Landscapes • Individual rocks and boulders, often named: • Sojourner rover • Moe, showing æolian fluting and faceting • Shark, showing smooth, rounded pebbles and cobbles and sockets where they've fallen out -- perhaps a conglomerate of rock materials smoothed by: • transport? • wave action? • relithified? C.M. Rodrigue, 2016 Geography, CSULB

8. Mars: Fifth Order Landscapes • Individual rocks and boulders, often named: • Viking 1, Chryse Planitia, August 1976 and 1977 • Whale Rock and Big Joe (static.lukew.com/aeolian_image_15_bg.jpg) • Wind erosion exposes circular feature downwind of Whale Rock (A) • Wind erosion exposes rock surface next to Big Joe (B) C.M. Rodrigue, 2016 Geography, CSULB

9. Mars: Fifth Order Landscapes • Individual rocks and boulders, often named: • Mars Exploration Rovers Spirit and Opportunity • APXS spectra C.M. Rodrigue, 2016 Geography, CSULB

10. Mars: Fifth Order Landscapes • Individual rocks and boulders, often named: • Mars Exploration Rovers Spirit and Opportunity • APXS oxides and elements data taken from individual rocks • GEOG 400 geomorphic zonation based on PCA • Our own lab differentiating RATted, brushed, untouched rocks from soil C.M. Rodrigue, 2016 Geography, CSULB

11. Mars: Fifth Order Landscapes • Frost deposits: • Viking landers • Viking 2 caught frost forming in Utopia Planitia C.M. Rodrigue, 2016 Geography, CSULB

12. Mars: Fifth Order Landscapes • Frost deposits: • Phoenix lander • Was killed by the crush of dry ice forming on its solar panels in the winter C.M. Rodrigue, 2016 Geography, CSULB

13. Mars: Fifth Order Landscapes • Polygon-patterned ground: • Phoenix lander • Got images of polygon patterning at a spatial scale similar to what we see on Earth • Image in middle from HiRISE • Image on left of Devon Island, Canada C.M. Rodrigue, 2016 Geography, CSULB

14. Mars: Fifth Order Landscapes • Dust devil activity and tracks: • Phoenix lander • Its Telltale instrument caught evidence of wind by monitoring the movements of a tube on a string • There's an episode where the whole contraption shakes, thought to be a dust devil hitting Phoenix C.M. Rodrigue, 2016 Geography, CSULB

15. Mars: Fifth Order Landscapes • Dust devil activity and tracks: • Spirit • Caught a swarm of them nearby • Dust devils may have extended the life of the rovers by cleaning their solar panels! C.M. Rodrigue, 2016 Geography, CSULB

16. Mars: Fifth Order Landscapes • Sand and dust streaks and dunes: • Viking 1 • dunes and streaks C.M. Rodrigue, 2016 Geography, CSULB

17. Mars: Fifth Order Landscapes • Sand and dust streaks and dunes: • Pathfinder • dunes and streaks • note classic barchans to right (below) • Sojourner on a transverse dune (Mermaid) C.M. Rodrigue, 2016 Geography, CSULB

18. Mars: Fifth Order Landscapes • Sand and dust streaks and dunes: • Viking 1 (Chryse Planitia) • hollow at rock base, streakiness C.M. Rodrigue, 2016 Geography, CSULB

19. Mars: Fifth Order Landscapes • Fresh gullies: • HiRISE imager on MRO • What look like fresh gullies in Promethei Terra • MOC imager on MGS • Before and after images in Terra Sirenum C.M. Rodrigue, 2016 Geography, CSULB

20. Mars: Fifth Order Landscapes • Fresh gullies: • HiRISE imager on MRO • What look like fresh gullies in Promethei Terra • MOC imager on MGS • Before and after images in Terra Sirenum C.M. Rodrigue, 2016 Geography, CSULB

21. Mars: Fifth Order Landscapes • Fresh gullies: • HiRISE imager on MRO • Recurring slope lineæ in Valles Marineris (brines dampening soil seasonally) C.M. Rodrigue, 2016 Geography, CSULB

22. Mars: Fifth Order Landscapes • Fresh gullies: • Found between ~30° - 65° both north and south • More common in Southern Hemisphere • Found on steep slopes • Commonly on crater walls • Aspect: • Both orientations found in all latitudes, but equatorward-facing is about 65% of all cases • Some 35%, however, are poleward-facing C.M. Rodrigue, 2016 Geography, CSULB

23. Mars: Fifth Order Landscapes • Fresh gullies: • Found between ~30° - 65° both north and south • Bridges and Lackner (2006) JGR Planets (yellow and red are gullies, green is seach area, light blue is MOC image footprints used, dark is THEMIS) C.M. Rodrigue, 2016 Geography, CSULB

24. Mars: Fifth Order Landscapes • Fresh gullies: • Might not be water or brine • Something dry and granular? • Some gullies form in winter • No chance of liquid water • CO2 frost deposits as fine granular particles that can flow downslope, entraining dust/sand in avalanche • Flow may be fluidized C.M. Rodrigue, 2016 Geography, CSULB

25. Mars: Fifth Order Landscapes • Fresh gullies: • Bridges and Lackner (2006) model • Obliquity and latitude affect formation and erosion of mantling units most susceptible to gullying C.M. Rodrigue, 2016 Geography, CSULB

26. Mars: Fifth Order Landscapes • Blueberries: • Opportunity sent to Meridiani Planum because of hæmatite signal • Hæmatite an advanced water alteration product of olivine in basalt • Olivine → iddingsite → gœthite → hæmatite • Hæmatite in abundance, often as small concretions: blueberries C.M. Rodrigue, 2016 Geography, CSULB

27. C.M. Rodrigue, 2016 Geography, CSULB Mars Order of Relief • This concludes the “Orders of Relief” discussion • We've gone over all of Mars at the higher orders • First order: the great crustal dichotomy and Tharsis • Second order: the huge, conspicuous features • Third order: Martian geological history • We've had a more selective tour of the lower orders • Selection organized around physical processes active on Mars • Fourth order: landscapes, often orbiter image scale • Fifth order: small features, often rover or lander scale • Now, let's consider Mars' atmosphere, weather, and climate