Evidence of Glacial Geomorphology on Mars

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					Evidence of Glaciers on Mars




                       Hubblesite.org

 TJ Schepker   G565 Glacial Geomorphology   Spring 2009
                         Overview

A. Background on Mars              D. Impact Craters
                                      “Normal” crater ice
B. Polar Ice on Mars                  Rock glaciers in craters
   Fingerprint terrain
   Polar dunes                     E. Mountain/piedmont glaciers
   Layered deposits                   Model
                                      Morphological support
C. Model for rock glacier             Analysis of Olympus Mons
   formation
   Hellas region                   F. Ground Ice?
   Glacier tongue
                                   G. Conclusions

          TJ Schepker    G565 Glacial Geomorphology   Spring 2009
                         Background
Mars compared to earth:

•Smaller
•Thinner atmosphere
•Lower gravity
•Less sunlight = colder
•2 compositions of Ice: Water
Ice and Carbon Dioxide Ice

Obliquity, eccentricity (ellipsoid)
combine to allow ice and glacial
formation on Mars



           TJ Schepker    G565 Glacial Geomorphology   Spring 2009
The Obvious place to look? The Poles!
Poles show seasonal
variation:

•Winter = Expansion of Ice
“sheets”

•Condensation of Carbon
Dioxide Ice at temperatures
as low as -150 °C

•Summer = Evaporation of
carbon dioxide ice

•only water ice remains
                                                 Mars Express/ESA, HIRISE/NASA


          TJ Schepker     G565 Glacial Geomorphology          Spring 2009
              “Fingerprint” Terrain

•Only poles show
uncovered ice in
significant quantities

•Spiral, lobate pattern
common in polar ice

• Fingerprint “texture”
formed via wind and
Aeolian processes


                                                       HIRISE/NASA

        TJ Schepker       G565 Glacial Geomorphology    Spring 2009
                  Polar Dune Terrain




              HIRISE/NASA


•Evidence of geyser activity?

         TJ Schepker        G565 Glacial Geomorphology   Spring 2009
              Layered Deposits




               •Alternating
               layers of ice
               and dust/rock

               •Potentially will
               give us climatic
               record
                                                Mars Express/ESA, HIRISE/NASA

TJ Schepker        G565 Glacial Geomorphology        Spring 2009
Model of Glacial Formation and Evolution:
              Rock Glaciers

•No Ice at surface except at
or near poles

•Ice originates from below the
surface and “ponds”

•Sublimation of uncovered
ice under present conditions
makes it extremely difficult to
see glacier evolution



         TJ Schepker    G565 Glacial Geomorphology   Spring 2009
Example of the Model? Hellas Region




                        MRO/NASA




     TJ Schepker   G565 Glacial Geomorphology   Spring 2009
  Glacial “Tongue” - Hellas Region




•Eskers

•Very different morphology than most

•Thought to represent a “wet” galcier
                                                       Both-HIRISE/NASA

          TJ Schepker   G565 Glacial Geomorphology   Spring 2009
Where Else To Look? Impact Craters…

 •Provide shelter for ice
 against sun exposure

 •Ice must be transported from
 poles due to seasonal shifts
 in atmospheric conditions

 •Impacts can also release
 liquid water or provide a
 pathway for its escape from
 below

                                                     Mars Express/ESA, HIRISE/NASA


          TJ Schepker   G565 Glacial Geomorphology          Spring 2009
       Crater Based Rock Glacier

•Like the debris fan
around Hellas, many
thought this was a fluvial
sediment accumulation

•Mars Reconnaissance
Orbiter (MRO)
demonstrated the
presence of ice just
below the surface


                                                   MRO/NASA


        TJ Schepker   G565 Glacial Geomorphology    Spring 2009
   Another Target For Ice? Mountains!
Olympus Mons:

•Most massive volcano in the
solar system

•Surrounded by large cliffs but
has shallow slopes

•~86,600 ft above MSL of
Mars (~3x as high as Everest)

•~342 miles wide
                                                      Milkovich et al., 2005

•Caldera: ~1960 mi2
           TJ Schepker   G565 Glacial Geomorphology          Spring 2009
Model of Glacial Formation and Evolution:
             Olympus Mons
•Much closer to
equator

•Ice flows down slope
on Olympus Mons

•Exposed Ice will
sublimate at lower
elevation

•Mass wasting and
effective debris
                                                     Milkovich et al., 2005
coverage important
to survival
         TJ Schepker    G565 Glacial Geomorphology             Spring 2009
      Different Morphologies on Mars
A) Ganges Chasma, Valles
  Marineris
radial grooved texture of
debris apron

B) Daedalia Planum
blocky texture of flow
   surface with many
   tongues and toes

C) Olympus Mons scarp
sub parallel arcuate ridges
in the debris apron
                                                      Milkovich et al., 2005


           TJ Schepker   G565 Glacial Geomorphology         Spring 2009
Olympus Mons Geomorphology




                   Milkovich et al., 2005

  TJ Schepker   G565 Glacial Geomorphology   Spring 2009
                        Ground Ice?
•Network of polygonal
cracks and elongated,
scallop-shaped
depressions

•Similar to thermal
contraction cracks in
periglacial and alpine
regions                                               HIRISE/NASA



•Steep pole/gentle                   Western Utopia Planitia,
equator facing slopes                  northern lowlands


          TJ Schepker    G565 Glacial Geomorphology       Spring 2009
                     Conclusions
•Glacial environments do and have existed on Mars for a
long time

•Ice is found in both polar and non-polar regions, but
much of the geomorphology on Mars is poorly understood

•A diverse set of terrains and morphologies exist
suggesting complex and diverse micro-climatic conditions
on Mars

•Layered polar deposits should give a detailed climatic
record similar to that obtained from Antarctic ice cores

•Most ice on Mars (non-polar) originates from below the
surface and depends on rock and sediment coverage to
avoid sublimation

       TJ Schepker      G565 Glacial Geomorphology   Spring 2009
                                    Questions?


         HIRISE/NASA                References                                    HIRISE/NASA


ESA: Mars Express. European Space Agency. <http://www.esa.int/SPECIALS/Mars_Express/>.

Head J.W. et al., 2005. Tropical to mid-latitude snow and ice accumulation, flow and glaciation on
Mars. Nature, 434: March 17, 346-351

HIRISE: High Resolution Imaging experiment. Department of Planetary Sciences, Lunar and
Planetary Institute, The University of Arizona. <http://hirise.lpl.arizona.edu/>.

Milkovich, S.M. et al., 2005. Debris-Covered Piedmont Glaciers Along The Northwest Flank Of The
Olympus Mons Scarp: Evidence For Low-Latitude Ice Accumulation During The Late Amazonian Of
Mars. M.S. Thesis, Brown University.

NASA , website. <http://www.nasa.gov>.

The Hubble Telescope. NASA. <http://www.hubblesite.org>.



                TJ Schepker             G565 Glacial Geomorphology         Spring 2009

				
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