First International Conference on Mars Polar Science
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ORIGINS AND MORPHOLOGY OF SIMILAR LANDFORMS IN TERRESTRIAL AND MARTIAN
POLAR REGIONS. A. P. Kapitsa1, A. A. Loukashov2, and A. G. Marchenko3, 1Department of Environmental
Management ([email protected]), 2,3Department of Geomorphology and Paleogeography
([email protected]), 1,2,3Faculty of Geography, Moscow State University, Vorobievy Gory, Moscow,
119899, Russia.
Introduction: The comparison between the geology and geomorphology of terrains near the polar caps
of Mars and the Earth is a difficult task. The contemporaneous ice sheets and caps of Antarctica and the
Arctic islands are either surrounded by water or by
mountains. However giant Pleistocene ice sheets
formed the distinctive complexes of landforms and
deposits over a much larger area. It is possible to find
distant analogues between landforms in martian polar
layered deposits and adjacent terrains, in regions of
modern and relic terrestrial periglacial landforms.
Ice-rich silt deposits in the Arctic are widespread
and form smooth plains easily eroded by water (Figure
1). Their thickness reaches 80-100 m in northern Asia
[13]. Several hypotheses (niveo-eolian, fluvial, fluvioglacial and termokarst) have been proposed by different authors to explain the formation of these deposits. If the niveo-eolian hypothesis is correct, then these
terrestrial plains could be analogous to martian terrains which are thought to consist of layered deposits
(silt+sand+ice [6, 10] ).
Figure 1. The ice-rich silt deposits with ice wedges
on Bolshoj Lyahovsky island (74o N, 142o E). Photo
by M. Grigoriev.
Dunes: There are landforms and deposits of a distinct niveo-eolian origin on the Earth which can be
compared to martian ones [4]. Large dunes of different kinds are known to consist of ice-cemented sand
and snow layers on the Earth. In the Antarctic dry
valleys, dunes 100 m long and up to 13 m high form
an erg [S. M. Myagkov, personal communication; 12].
There are barchanoid and transverse ridges in this
area. The dunes in Thelon Basin (Canada) are even
taller - up to 24 m [2]. The fact that there are many
ventifacts near the boundary of Antarctic ice sheet also
shows that the eolian processes are active here.
Eolian dunes are much more common for the polar
regions of Mars than on the Earth. Studies of these
reveal recent (several million years) to modern eolian
activity [7, 8, 9, 11].
Although there is evidence of dunes forming out of
material from the polar layered deposits eroded by
wind [9], transverse ridges in the bell-shaped dilation
of Chasma Boreale remain giant current ripples
analogous to those in terrestrial catastrophic outflows,
described in [1, 3], only much larger. If this is the case
then it is possible that the catastrophic outflow could
have been caused by sudden melting of ice e.g. after
an asteroidal impact.
Conclusion: Martian polar terrains consist of silt
and sand cemented by volatiles [5, 6] similar to the
niveo-eolian complexes of the Arctic and Antarctic.
Both are probably formed by wind action and precipitation. So such geologically young landforms as icerich silt plains and niveo-eolian dunes of polar regions
of the Earth may be distant embrional analogues of
forming for a long time thick martian polar complexes.
References: [1] Baker V. (1982) The channels of
Mars, Univ. of Texas Press, Austin, 197 pp. [2] Bird
J. B. (1951) Geog. Bull. I, 14-29. [3] Butvilovsky V.
V. (1993) Paleogeography of the last glaciation and
Holocene of Altay (in Russian), Tomsk Univ. Press,
Tomsk, 253 p. [4] Cailleux A. (1972) Cahiers Geog.
Quebec 16(39), 377-409. [5] Condit C. D. and Soderblom L. A. (1978) USGS Map I-1076 (MC-30). [6]
Malin M. C. (1986) Geophys. Res. Lett. 13, 444-447.
[7] Marchenko A. G. et al. (1996) Space and Planet.
Sci. 14, Suppl. III, C792. [8] Marchenko A. G. et al.
(1997) LPS XXVIII, 867-868. [9] Thomas P. C. (1988)
NASA Conference Publication 10021, 32-34. [10]
Thomas P. C. and Weitz C. (1989) Icarus 81, 185215. [11] Tsoar H. et al. (1979) JGR 84, 8167-8180.
[12] Webb P. N. and McKelvey B. D. (1959) New
Zeland J. Geol. and Geophys. 2, 120-36. [13] Yershov
E. D. et al. (1987) Petrography of frozen rock (in
Russian), Moscow Univ. Press, Moscow, 311p.