EPISODICITY OF VOLCANIC AND FLUVIAL

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EPISODICITY OF VOLCANIC AND FLUVIAL PROCESSES ON
MARS G. Neukum1, A.T. Basilevsky1,2, and the
HRSC Team 1Freie Universitaet Berlin,
Malteserstr., 74-100, Haus D, 12249 Berlin
Germany 2 Vernadsky Institute, Kosygin Str.,
19, 119991 Moscow, Russia. Contact
gerhard.neukum_at_fu-berlin.de
The first Moscow Solar System Symposium
(1M-S3) Mars system studies Space Research
Institute, Moscow, Russia October 11 15, 2010
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Global geologic map of Mars, Tanaka Scott, 1986
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Shaded relief map of Mars
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Areas of study
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Mangala Valles
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Crater count results for Mangala Valles
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Age estimates for different units
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Histogram of age estimates for Mangala Valles
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Summary of age histograms for all 12 study areas
The histogram shows peaks of volcanic activity
and fluvial/glacial activity The most
distinctive peaks are at 3.33.8 Ga, 1.82
Ga, 1.21.6 Ga, 300 to 800 m.y., 200 m.y.,
and 100 m.y. ago. In some areas, there is
indication of an additional peak around 2.22.5
Ga ago. The most prominent peaks are within the
latest 11.5 Ga and around 3.5 Ga. The period
between 2 and 3 Ga shows much less
activity. All peaks showing up in the fluvially
affected areas also roughly show up in the
volcanic areas and vice versa. Peaks of some of
the cratering ages correlate with the age groups
of Martian meteorites.
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Large-scale episodicity of igneous activity on
Earth
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Large-scale episodicity of mare basalt volcanism
on the Moon
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Conclusions There has been volcanic and
fluvial/glacial geologic activity on the Martian
surface at all times from gt4 Ga ago until today.
This activity was rather continual if to
consider all 12 studied regions but with
episodic increases of intensity of both volcanic
and fluvial/glacial processes at 3.83.3 Ga,
2.01.8 Ga, 1.6 to 1.2 Ga, 800 to 300 m.y.,
200 m.y., and 100 m.y., and a possible weaker
phase around 2.52.2 Ga ago. The episodes we
find on the Martian surface in the crater
frequency analyses are well coincident with some
age groups of the Martian meteorites found in
the radiometric age data. Episodes of volcanic
activity were probably initiating the
fluvial/glacial activity explaining their
correlation in time.
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Danke schoen! ??????? ?? ????????! Thank you for
your attention!