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8/3/2019 Current State and Disintegration of Rock-Glacier Landforms in Tempe Terra Mars - S Van Gasselt Et Al 2007
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European Space Agency
European Mars Science and Exploration Conference: Mars Express & ExoMars
ESTEC, Noordwijk, The Netherlands, 12 - 16 November, 2007
Current State and Disintegration of Rock-Glacier Landforms in Tempe Terra, Mars S. van Gasselt1, E.Hauber, G. Neukum
1. 1Institute of Geological Scienes, Planetary Sciences and Remote Sensing. 2German Aerospace Center,
Institute of Planetary Research. [email protected]
Abstract: The fretted terrain at the Martian
dichotomy boundary exhibits a variety of creep-related morphologies generally known as lobate
debris aprons and lineated valley fills [1-5]. We here
investigate debris aprons and adjacent terrain in the
Tempe Terra/Mareotis Fossae region (270-294E,
46-54N) and provide observational evidence for
several stages and mechanisms of debris supply at
remnant massifs, i.e., rock fall and landsliding in a
sequence with (cyclic) deposition and disintegration
of a widespread surficial mantling deposit.
The mantling deposit disintegrates by processes
similar to thermokarstic degradation as indicated by
heavily dissected areas and characteristic shallow
and aligned circular depressions. Correlations ofgeomorphometric key parameters in a global context
show that the Tempe Terra/Mareotis Fossae debris
aprons are comparable to other characteristic
locations of debris aprons on Mars. The values for
these key parameters do not show any significant
dependencies on geographic locations (e.g.,
latitudes), suggesting that an equilibrium state of
debris advance and deformation has been reached
globally before disintegration processes initiated.
The latest phase of apron deformation has been
active in a geologically recent time as
geomorphologic features appear pristine and crater
size-frequency measurements on selected apronsyield ages in the range of 50-100 Ma only and
would support the idea of climatically-driven
landform degradation at Martian mid-latitudes.
Degradation of surfaces is also confirmed by
observations of theoretically derived cross-profiles
of debris aprons and lineated valley fill units. Both
creep-related landforms show an unsatisfactory fit to
the model-curve. This divergence might either be
caused by limitations in the flow relation used for
the model or by the eroded state of these landforms,
similar to what is known from terrestrial rock-
glacier research [e.g., 6-7].
References: [1] Sharp, J. Geophys. Res., 78, pp.
4073, 1973; [2] Carr and Schaber, J. Geophys. Res.
82(11), pp. 4039, 1977; [3] Sqyures, Icarus 34(3), pp. 600,
1978; [4] Squyres, J. Geophys. Res., 84(B14), pp. 8087,
1979; [5] Lucchitta, J. Geophys. Res. 89(B1), pp. 409,
1984; [6] Ikeda and Matsuoka, Permafrost Perigl. Proc.,
13(2), pp.145, 2002 [7] Berthling et al., Permafrost Perigl.
Proc., 9(2), pp. 135, 1998; [8] Mangold and Allemand,
Geophys. Res. Lett., 28(3), pp. 407, 2001.
Figure 1. Map of the Mareotis Fossae/Tempe Terra region with location of lobate debris aprons that were investigated
morphologically and morphometrically, Frames refer to HRSC (H), Viking (V) and MOC (M) image data.