Evidence of Glaciers on Mars TJ Schepker G565 Glacial GeomorphologySpring 2009 Hubblesite.org.

Evidence of Glaciers on Mars

TJ Schepker G565 Glacial Geomorphology Spring 2009

Hubblesite.org

Overview


A. Background on Mars

B. Polar Ice on MarsFingerprint terrainPolar dunesLayered deposits

C. Model for rock glacier formationHellas region Glacier tongue

D. Impact Craters“Normal” crater iceRock glaciers in craters

E. Mountain/piedmont glaciersModelMorphological supportAnalysis of Olympus Mons

F. Ground Ice?

G. Conclusions

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

The Obvious place to look? The Poles!


Mars Express/ESA, HIRISE/NASA

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

“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

Polar Dune Terrain


HIRISE/NASA

•Evidence of geyser activity?

Layered Deposits


•Alternating layers of ice and dust/rock

•Potentially will give us climatic record



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

Example of the Model? Hellas Region


MRO/NASA

Glacial “Tongue” - Hellas Region


•Eskers

•Very different morphology than most

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

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


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

Another Target For Ice? Mountains!


Milkovich et al., 2005

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

•Caldera: ~1960 mi2

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 coverage important to survival


Different Morphologies on Mars


A) Ganges Chasma, Valles Marineris

radial grooved texture ofdebris apron

B) Daedalia Planumblocky texture of flow

surface with many tongues and toes

C) Olympus Mons scarp sub parallel arcuate ridges

in the debris apronMilkovich et al., 2005

Olympus Mons Geomorphology



Ground Ice?


•Network of polygonal cracks and elongated, scallop-shaped depressions

•Similar to thermal contraction cracks in periglacial and alpine regions

•Steep pole/gentle equator facing slopes

HIRISE/NASA

Western Utopia Planitia, northern lowlands

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

References


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>.

Questions?

HIRISE/NASAHIRISE/NASA

Evidence of Glaciers on Mars TJ Schepker G565 Glacial GeomorphologySpring 2009 Hubblesite.org.

Documents

marspolar ice

presence of ice

olympus monsexposed

rock glaciersno ice

colder2 compositions

alternating layers of

mi2 model of glacial

polar ice fingerprint