Morphology of the Martian Dark Dune Spots

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Morphology of the Martian Dark Dune Spots
András Horváth Konkoly Observatory, TIT Budapest
Planetarium, planet_at_mail.datanet.hu (Eloadás az
MTA Geonómiai Bizottságának Szádeczky-emlékülésén,
2003. okt. 21.-én)
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Co-workers

• Tibor Gánti
• emeritus professor of theoretical biology
• Eörs Szathmáry,
• biology professor, Eötvös University and
  permanent fellow of the Collegium Budapest,
  Szaniszló Bérczi,
• associate professor, Eötvös University
• Albert Gesztesi,
• dep.director, TIT Budapest Planetárium

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Introduction-I Dark dune spots (DDSs) are
annually recurring geomorphological features of
martian dark dunes located between the South Pole
and 50 degrees latitude
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Introduction-II Frost cover first appears on
dark dunes in autumn. They defrost towards the
second half of winter and in spring, when dark
spots are formed.
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Introduction-III

• DDSs were first observed in narrow-angle MGS MOC
  images in years 1998 to 2001. By now, several
  thousand such formations have been identified.
• All of the observed features of DDSs
• can be explained by a
• biological hypothesis.

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Observations - I

• DDSs have an isotropic circular form and are
  superimposed on the local topography,
• i.e., small scale groove structure
• of the frosted surface of snow/ice cover.

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Observations - II

• The process
• of DDS formation
• begins below the
• frosted layer.
• DDSs are shallow
• crater-like holes in the layer of
  precipitated snow/ice.

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Observations - III

• On slopes,
• the spots are elongated downwards,
• taking
• ellipsoidal or
• fan-like shape or creek-like flows
• depending on
• the steepness
• of the slope.

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Observations - IV

• The spring configuration of DDSs appears as the
  summer configuration of light grey patches in the
  dark dune fields. There are localized causes for
  spot formation.

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Observations - V

• DDSs have a seasonal changes
• from winter to summer.

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Observations VIDDSs have a massiv annual
reappearanceon the same places. The dinamics of
the reappearance depend on local meteorological
condicions.
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Biological hypothesis for DDSs genesis Martian
Surface Organisms (MSO)

• Organisms
• on the soil, below the ice, warm up by the
  absorption of sunlight and melt the water ice
• around them.
• The CO2 ice cover disappears
• in the center,
• where the melting starts.
• When water evaporates the organisms dessicate and
  
• the dark naked soil
• can be seen.

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MARS ODYSSEY data
Efficient pigments water lens UV screening
and insulation by ice layer liquid
phase water is abundant in the soil several
months for reproduction terrestrial analogues
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ConclusionIf the biogenic hypothesis is
correct, it means that, at exceptional sites and
under exceptional circumstances, photosynthetic
organisms still dwell on the Martial
surface.This claim will be substantiated as
far as possible by the extensive use of the data
obtained by the Mars Express mission.
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Proposal for MARS EXPRESS IMars Express coud
provide imaging and spectroscoping observations
for detailed study of the dynamics of DDSs on the
selected areas (Pityusa Patera and Inca City
region)
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Proposal for MARS EXPRESS IIImaging and
spectroscoping observations on the selected
areas in the Inca City region