Mars: First Order Landscapes The Great Crustal Dichotomy

1. Geography 441/541 S/14 Dr. Christine M. Rodrigue Mars: First Order LandscapesThe Great Crustal Dichotomy C.M. Rodrigue, 2014 Geography, CSULB

2. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes

3. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes

4. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • On Earth, the orders of relief scheme • Is sometimes seen in geography textbooks • Organizes topographic variation in a scale-dependent manner • Geographers often focus on • Spatial analysis of particular phenomena • Regional synthesis to integrate assemblages of phenomena • Scales at which processes and regional patterns operate • The interactions among phenomena at different scales

5. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Examples of interactions among scales • In spatial statistics: the Modifiable Areal Unit Problem (MAUP) • In human geography: local cultural and political responses to global economic and political processes • Biogeography: alpha, beta, and gamma measures of biodiversity • Geomorphology: "megageomorphology" has emerged as remote sensing technology has made the simultaneous examination of form and process at large scale (small map scale) possible

6. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • For Mars, a handy descriptive scheme for handling the regional variations in Mars’ physical landscapes • The “First Order of Relief” = the crustal dichotomy • The northern lowlands: Vastitas Borealis • The southern highlands • If Earth’s oceans evaporated (which they will …), there would remain a crustal dichotomy here • Former ocean basins: low elevation, thin crust, basaltic, with a veneer of pelagic sediments • Former continents: high elevation, thick crust, granitic rocks and their extrusive igneous, sedimentary, and metamorphic derivatives

7. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Regional subdivisions: • Utopia Planitia • North Polar Basin • Embayments: • Acidalia Planitia • Chryse Planitia • Amazonis Planitia • Arcadia Planitia • Isidis Planitia C.M. Rodrigue, 2014 Geography, CSULB

8. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Relatively young surface • Smooth with few craters • This is exactly what you’d expect if Mars had had an ocean • It could be expected to receive sediments from rivers, floods, and coastal processes and create terrigenous sediments nearshore • They would be turned into minerals that would eventually precipitate out of the water column onto the abyssal floor • The oceans would thus cover the underlying original rock surface, much as pelagic sediments here do

9. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Further suggestions of an ocean: • Drainage of Martian outflow channels and valley networks • This is also exactly what you’d expect if Mars had had an ocean to serve as base level for stream networks

10. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Drainage: • Valles Marineris' outflow channels, which drain into Chryse Planitia • Nanedis north of Ganges • Ares and Aram Chaos • Argyre to Aram and Ares C.M. Rodrigue, 2014 Geography, CSULB

11. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes

12. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Even better: Coastlines!? • Transition between the southern highlands and the northern lowlands is quite abrupt

13. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes

14. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Even better: Coastlines!? • Terraces on the Arcadia side of Alba Patera C.M. Rodrigue, 2014 Geography, CSULB

15. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Even better: Coastlines!? • Tim Parker’s analysis of Viking imagery C.M. Rodrigue, 2014 Geography, CSULB

16. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Even better: Coastlines!? • Tim Parker’s analysis of Viking imagery (1994) • His and others’ re-analysis using MOC imagery seemed to debunk his argument, which even he admitted in 2001 • But it’s as though the new imagery is so fine in resolution that it can’t detect the coarser scale at which this putative ocean’s coastline features might exist • MOLA suggests that, in fact, at least one of the “coastlines” is at the same elevation (water seeks a level constant with respect to the geoid)

17. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Plot complication • That "ocean" floor is dominated by andesitic rock • Not sediments with minerologies consistent with precipitation out of water. • No carbonates! No ocean?

18. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • About those andesites • "Surface Type 1" (basalts dominating the southern highlands) • "Surface Type 2" (andesites and andesitic basalts dominating the northern lowlands) C.M. Rodrigue, 2014 Geography, CSULB

19. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes

20. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Vastitas Borealis • Rampart craters C.M. Rodrigue, 2014 Geography, CSULB

21. C.M. Rodrigue, 2014 Geography, CSULB Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • The Southern Highlands • Mostly 1-5 km above the mean Martian geoid • Versus 0-3 km below for the northern lowlands • Sharp ~1 km scarp dividing the two

22. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Arabia Terra C.M. Rodrigue, 2014 Geography, CSULB

23. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Noachis Terra is another old land (for which “Noachian era” named) • West of Hellas, east of Argyre • Signs of water or fluid • Channels • Softened terrain C.M. Rodrigue, 2014 Geography, CSULB

24. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Hellas, with Isidis and Utopia from the Northern Lowlands beyond C.M. Rodrigue, 2014 Geography, CSULB

25. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Noachis Terra, Holden Crater, Vallis Uzboi C.M. Rodrigue, 2014 Geography, CSULB

26. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Noachis Terra, Holden Crater, alluvial fan/bajada? C.M. Rodrigue, 2014 Geography, CSULB

27. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Syrtis Major Planum, volcanic province, basaltic, not dusty C.M. Rodrigue, 2014 Geography, CSULB

28. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Terra Tyrrhena, battered basalt, fluvial dissection, mineral precipitation (sulfates?), wind deposition C.M. Rodrigue, 2014 Geography, CSULB

29. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Promethei Terra, east of Hellas, basaltic, landslides, dust devils C.M. Rodrigue, 2014 Geography, CSULB

30. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Cimmeria Terra, basaltic, cratered, E of Hellas, S of Elysium, SW of Tharsis, Ma’adim Valles C.M. Rodrigue, 2014 Geography, CSULB

31. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Ancient, battered terrain • Margaritifer Terra, basaltic, cratered, fluvial alteration, chaos terrain, east of Valles Marineris outflow, west of Meridiani C.M. Rodrigue, 2014 Geography, CSULB

32. Mars: First Order Landscapes • The “Orders of Relief” for Martian Landscapes • Basalt terrain and dust dominate the Southern Highlands • Spectra showing high proportions of basalt shown in the green • Andesite shown in the red channel • Hæmatite shown in blue (small area) • Dust-dominated areas come out brown C.M. Rodrigue, 2014 Geography, CSULB