Gravitational Spreading of High Wallslopes on Mars: Evidence of Past Equatorial Glaciations

1. Gravitational spreading of high wallslopes on Mars: evidence of past equatorial glaciations GEOMORPHOLOGY FOR MARTIAN ADAPTATION TO CHANGING TROPICAL ENVIRONMENTS Daniel MEGE Olivier BOURGEOIS Planetology and Geodynamics Lab, CNRS/Nantes University, France Laetitia LE DEIT Institute for Planetary Research, DLR Berlin, Germany Antoine LUCAS Division of Geological and Planetary Sciences, Caltech, Pasadena, U.S.A. Addis Ababa, IAG Meeting, February 21, 2011

2. talk by Mohammed Umer tomorrow 8 am! Glacial landforms in Bale Mountains, Ethiopia Dr. Tesfaye Korme H2O HIGH ELEVATION liquid ice pressure vapor Master of GIS and Remote Sensing field class in Bale Mountains, 2004 temperature

3. Mars - Valles Marineris rift Valles Marineris has recorded variations of morphogenetic conditions on Mars over ~3.5 Ga. Wallslope morphogenesis remains controversial.

4. Environment Fluids • Open air/fluvial? • Submarine/lacustrine? • Glacial/subglacial? • Water? • Ice? • Dry? 10 km

5. 1 Observations on topographic ridges, and terrestrial analogs

6. Observation 1: Crestal grabens I U S C H A S M A I U S C H A S M A G E R Y O N M O N T E S Doppelgrate (Penck, 1894; Paschinger, 1928) double crest lines Ridge-top splitting

7. I U S C H A S M A 5 km glacial valley glacial valley B O D E N E C K Austrian Alps 2 km

8. 1 km Observation 2: Uphill-facing scarps C A N D O R C H A S M A uphill-facingscarps M E L A S C H A S M A

9. HoherTrog OberesTörl Courtesy by Jürgen Reitner Austroalpine nappes, Austrian Alps

10. M E L A S C H A S M A Austroalpine nappes, Austrian Alps HoherTrog uphill-facingscarps Courtesy by Jürgen Reitner

11. I U S C H A S M A 11° G E R Y O N M O N T E S HiRISE image + HRSC topography Observation 3: Graben floor deformation GERYON MONTES IUS CHASMA

12. Synthesis of observations mineralogy from hyperspectral modelling after Roach et al., 2010

13. Tatra Mountains (Slovakia and Poland) Nemčok, 1972; Kellog, 1984 Sackung Deep-Seated Gravitational Spreading Historic study areas: Tatra Mountains Tyrol Observation sites: between valleys that were glaciated during the Quaternary: Carpathians, Alps of Europe, Japan, and New Zealand; Cascades, U.S. and Canadian Rockies, Alaska, Andes, Scotland and England Caledonides, Himalaya Western Tatras Jahn, Z. Geomorph., 1964 uphill-facing scarps graben Reitner and Linner, 2009 Oberes Törl, Austrian Alps

14. Valles Marineris crestal grabens and uphill-facing scarps

15. Association with landslides Coprates landslide arrowhead-shaped debris apron

16. Arrowhead-shaped debris apron is diagnostic of steep initial failure dip angle. landslide failure plane steepness failure plane initial slope z This is consistent with triggering from deep-seated gravitational slope deformation. 3 km 20 km 15 km 12 km Lucas et al., 2009 increased likelihood of normal fault control S1 S2 S3 COPRATES LANDSLIDE Granular landslide modelling

17. July 29, 1998, debris flow Mount Meager, British Columbia 1998 debris flow Sudden debris flow after decades of slow deep-seated gravitational slope deformation uphill-facing scarps historical rock avalanches … again a post-glacial event! Bovis and Jakob, 2000

18. 2. Is sackung always postglacial?

19. spreading ridge cohesion loss Oberes Törl, Austrian Alps Courtesy by J. Reitner Possible origin from previous works

20. postglacial trigger (ridge debuttressing/glacial unloading): 41 44 sackung trigger studies in international peer-reviewed publications Kobayashi, K. Periglacial morphology of Japan. Biuletyn Periglacjalny 4, 15-36 (1956). Beck, A. C. Gravity faulting as a mechanism of topographic adjustment. New Zealand J. Geol. Geophys. 11, 191–199 (1968). Tabor, R. W. Origin of ridge-top depressions by large-scale creep in the Olumpic Mountains, Washington. Geol. Soc. Am. Bull. 82, 1811-1822 (1971). Radbrush-Hall, D. H., Varnes, D. J. & Savage, W. Z. Gravitational spreading of steep-sided ridges ("sackungen") in western United States. Int. Assoc. Eng. Geol. Bull. 14, 28-35 (1976). Bovis, M.J. Uphilll-facing (antislope) scarps in the Coast Mountains, southwest British Columbia. Geol. Soc. Am. Bull. 93, 804-812 (1982). Beget, J. E. Tephrochronology of antislope scarps on an alpine ridge near Glacier Peak, Washington, U.S.A. Arctic Alpine Res. 17, 143-152 (1985). Holmes, G. & Jarvis, J.J. Large-scale toppling with a sackung type deformation at Ben Attow, Scotland. Q. J. Eng. Geol. London 18, 287-289 (1985). Thorsen, G. W. Splitting and sagging mountains. Washington Geologic Newsletter 17, 3-1 (1992). Reitner, J., Lang, M. & van Husen, D. Deformation of high slopes in different rocks after würmian deglaciation in the Gailtal (Austria). Quaternary Int. 18, 43-51 (1993). Ego, F., Sébrier, M., Carey-Gailhardis, E. & Beate, B. Do the Billecocha normal faults (Ecuador) reveal extension due to lithospheric body forces in the northern Andes? Tectonophysics 265, 255-273 (1996). Bovis, M.J. & Jakob, M. The July 29, 1998, debris flow and landslide dam at Capricorn Creek, Mont Meager Volcanic Complex, southern Coast Mountains, British Columbia. Can. J. Earth Sci. 37, 1321-1334. Agliardi, F., Crosta, G., & Zanchi., A. Structural constraints on deep-seated slope deformation kinematics. Eng. Geol. 59, 83-102 (2001). Smith, L.N. Columbia Mountain landslide: late-glacial emplacement and indications of future failure, Northwestern Montana, U.S.A. Geomorphology 41, 309-322 (2001). Jarman, D. & Ballantyne, C. K. Beinn Fhada, Kintal: An example of large-scale paraglacial rock slope deformation. Scottish Geog. J. 118, 159-168 (2002). Hermann, S. W. & Becker, L. P. Gravitational spreading ridges on the crystalline basement of the Eastern Alps (Niedere Tauern mountain range, Austria). Mitt.Österr. Geol. Ges. 94, 123-138 (2003). Holm, K., Bovis, M. & Jakob, M. The landslide response of alpine basins to post-Little Ice Age glacial thinning and retreat in southwestern British Columbia. Geomorphology 57, 201-216 (2004). Brückl, E. & Paroditis, M. Prediction of slope instabilities due to deep-seated gravitational creep. Natural Hazards Earth System Sci. 5, 155-172 (2005). Hetzel, R. & Hampel, A. Slip rate variations on normal faults during glacial-interglacial changes in surface loads. Nature 435, 81-84 (2005). Kinakin, D. & Stead, D. Analysis of the distributions of stress in natural ridge forms: implications for the deformation mechanisms of rock slopes and the formation of sackung. Geomorphology 65, 85-100 (2005) doi:10.1016/j.geomorph.2004.08.002. Korup, O. Geomorphic imprint of landslides on alpine river systems, southwest New Zealand. Earth Surf. Process. Landforms 30, 783-800 (2005). Ambrosi, C., & Crosta, G. B. Large sackung along major tectonic features in the Central Italian Alps. Eng. Geol. 83, 183-200 (2006). Hippolyte, J.-C., Brocard, G., Tardy, M., Nicoud, G., Bourlès, D., Braucher, R., Ménard, G. & Souffaché, B. The recent fault scarps of the western Alps (France): tectonic surface ruptures or gravitational sackung scarps? A combined mapping, geomorphic, levelling, and 10Be dating approach. Tectonophysics 418, 255-276 (2006), doi:10.1016/j.tecto.2006.02.009. Hippolyte, J.-C., Tardy, M. & Nicould G. Les failles récentes des Grands-Moulins (Savoie) : un sackung (tassement gravitaire) majeur dans les Alpes françaises. C. R. Geosci. 338, 734-741 (2006). Hürlimann, M., Ledesma, A., Corominas, J. & Prat, P. C. The deep-seated slope deformation at Encampadana, Andorra: representation of morphologic features by numerical modelling. Eng. Geol. 83, 343-357 (2006). Jarman, D. Large rock slope failures in the Highlands of Scotland: Characterization, causes and spatial distribution. Engineering Geol. 83, 161-182 (2006). Turnbull, J.M. & Davies, T.R.H. A mass movement origin for cirques. Earth Surf. Process. Landforms 31, 1129-1148 (2006). Wilson, P., & Smith, A. Gomorphological characteristics and significance of Lat Quaternary paraglacial rock-slope failures on Skiddaw Group terrain, Lake District, northwest England. Geografiska Annaler 88, 237-252 (2006). Ustaszewski, M., Hampel, A. & Pfiffner, O. A. Composite faults in the Swiss Alps formed by the interplay of tectonics, gravitation and postglacial rebound: an integrated field and modelling study. Swiss. J. Geosci. (Eclogae Geologicae Helvetiae) 101, 223-235 (2008). Hippolyte, J.-C., Bourlès, D., Braucher, R., Carcaillet, J., Léanni, L., Arnold, M., & Aumaitre, G. Cosmogenic 10Be dating of a sackung and its faulted rock glaciers, in the Alps of Savoy (France). Geomorphology108, 312-320 (2009). Reitner, J., & Linner, M. Formation and preservation of large scale toppling related to alpine tectonic structures – eastern Alps. Austrian J. Earth Sci. 102, 69-80 (2009).

21. postglacial trigger (ridge debuttressing/glacial unloading): 41 • possible in theory • never documented Rogers and Watkins, 2003 44 sackung trigger studies in international peer-reviewed publications

22. postglacial trigger (ridge debuttressing/glacial unloading): 41 • possible in theory • never documented Rogers and Watkins, 2003 2 reported (controversial) cases Loma Prieta, 1989 (Ponti and Wells, 1991) Northridge, 1994 (Harp and Gibson, 1996) 44 sackung trigger studies in international peer-reviewed publications

23. postglacial trigger (ridge debuttressing/glacial unloading): 41 • possible in theory • never documented Rogers and Watkins, 2003 1 unelucidated case (seismic shaking dismissed) South Italy (Rizzo and Leggeri, 2004) 2 reported (controversial) cases Loma Prieta, 1989 (Ponti and Wells, 1991) Northridge, 1994 (Harp and Gibson, 1996) 44 sackung trigger studies in international peer-reviewed publications

24. postglacial trigger (ridge debuttressing/glacial unloading): 41 • possible in theory • never documented Rogers and Watkins, 2003 River incision down to evaporite level Somali plateau (Mège et al., 2011) Canyonlands grabens-type spreading 1 unelucidated case (seismic shaking dismissed) South Italy (Rizzo and Leggeri, 2004) 2 reported (controversial) cases Loma Prieta, 1989 (Ponti and Wells, 1991) Northridge, 1994 (Harp and Gibson, 1996) 44 sackung trigger studies in international peer-reviewed publications SANDSTONE GYPSUM

25. -- Deglaciation seems by far to be the most likely sackung trigger in Valles Marineris -- 3. Are there other hints of ancient glaciers in Valles Marineris? • Glacial geomorphology: trimlines, moraines

26. trimlines formerly interpreted as normal fault scarps… 600 m Ius Chasma Mège, 1994 Peulvast et al., 2001 … but no clear length/displacement scaling law and poor segmentation! trimline (highest extent of glacier) Tana glacier, Alaska Molnia, 2004

27. I U landslide deposits S G E R Y O N M T S E O N I U S C H A A M F S L O O R 10 km Possible trimlines

28. trimline 5 km ?? Glacial receding since Little Ice Age trimline subglacial polished rocks 600 m 500 m chasma floor Thrilling Candor Chasma analog in Svalbard Svalbard Candor Chasma (Longyearbreen glacier) Evans, Quat. Sci. Rev., 2009

29. 2 km Is a glacier still present in Candor Chasma? +1200 m -4000 m lower layered deposits -4200 m -4500 m -3000 m DUST-COVERED GLACIER? EXPOSED SUBGLACIAL ROCKS TRIMLINE ablation moraine

30. 4. Does this fit Mars climate models? Comparison Mars General Circulation Model predictions

31. Climate Laskar et al., 2002 Levrard et al., 2004 During periods of high obliquity glaciers are predicted to form in tropical regions…

32. … in addition, in Valles Marineris sublimation is impeded due to the low elevation of the floor EARTH low elevation areas VALLES MARINERIS TROUGHS liquid EQUATORIAL THICKER ATMOSPHERE LOW ELEVATION ice equator now pressure vapor H2O temperature

33. net ice accumulation at 45° obliquity with available polar water ice Forget et al. 2006 Where does ice come from? Glacial deposits at the foot of Tharsis giant volcanoes Obliquity variations Laskar et al. 2002 45° VALLES MARINERIS snow redeposition in Valles Marineris net ice accumulation (mm/an) Madeleine et al. 2009

34. VARIABLES - obliquity - eccentricity - solar longitude - atmospheric dust content VALLES MARINERIS a wide range of conditions is suitable to ice accumulation in Valles Marineris if the Tharsis volcanoes are glaciated Madeleine et al. 2009 n e t i c e a c c u m u l a t i o n (mm/an)

35. Conclusions Morphology and structures within Valles Marineris point to the existence of widespreadancientvalley glaciers. The last equatorial glaciers on Earth are melting and sublimatingquickly… … but thick, equatorial glaciers maystillexist on Mars and those are sublimatingslowly! Marion Massé Olga Kromuszczyńska These conclusions are in agreement with the Mars General Circulation Model predictions for periods of highobliquity Check thesenames in future papers!

36. 100 m 2 km Glacial valley in southern Tibet Ius Chasma ppt available at http://dmzone.org