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Polygonated soils in the hyper-arid Atacama Desert and their relevance for patterned ground on Mars

Authors:

Abstract

Patterned grounds represent widespread and yet puzzling landscape features on Mars and periglacial regions on Earth and are believed to form through the repetitive deformation of the ground. A better knowledge of their distribution, morphological variability, and processes of formation can give clues about past and recent climatic conditions, the composition of the ground and presence of ground ice/water, which is critical for the search for life on Mars. The formation of patterned grounds in periglacial regions on Earth is based on the process of frost heave, where repeated freeze-thawing of water leads to the deformation of the ground (cryoturbation). On today’s Mars, the climatic conditions are not favorable for extensive freeze-thawing processes. However, vast quantities of ground ice enable frost heave processes through dry-cryoturbation. In addition, thermoturbation processes in ice-cemented soils are also assumed to be responsible for polygonated ground formation. Thereby, temperature di!erences lead to extensional and compressional forces in the salt cemented soil and can thus facilitate cracking and turbation processes. Patterned grounds are also observed in the hyper-arid Atacama Desert where cryoturbation can be excluded due to the high temperatures and thus polygonated soils do not necessarily indicate ground water. These features are assumed to have formed by a combination of thermoturbation and haloturbation where repeated precipitation and dissolution of salts deform the ground. Hence, in addition to periglacial processes (frost heave), patterned ground formation processes in hot hyper-arid regions (salt heave) should be considered for Mars as well. Therefore, we investigate the morphometric build-up of patterned grounds with photogrammetry techniques in combination with physicochemical soil analyses in the hyper-arid Atacama Desert and in periglacial Spitsbergen for comparing our results with those from Mars. Based on these data we aim to derive patterned ground formation processes and evaluate their habitability. A better understanding of patterned ground formation will also improve our understanding of the landscape evolution of the Atacama Desert, as well as for Mars and their potential past and present habitability
Polygonated soils in the hyper-arid Atacama Desert and their relevance for patterned
ground on Mars
CHRISTOF SAGER 1, ALESSANDRO AIRO1, FELIX L. ARENS1, MICKAEL BAQUÉ 2, JEAN-PIERRE DE VERA2, DIRK SCHULZE-MAKUCH 1
1Center of Astronomy & Astrophysics, Technical University Berlin, Berlin, Germany
2German Aerospace Center (DLR), Institute of Planetary Research, Management and Infrastructure, Research
Group Astrobiological Laboratories, Berlin, Germany
Presentation: Oral talk at AbGradE Symposium 2018, Berlin
Abstract:
Patterned grounds represent widespread and yet puzzling landscape features on Mars and periglacial regions on
Earth and are believed to form through the repetitive deformation of the ground (Hallet, 2013; Washburn, 1973).
A better knowledge of their distribution, morphological variability, and processes of formation can give clues
about past and recent climatic conditions, the composition of the ground and presence of ground ice/water,
which is critical for the search for life on Mars.The formation of patterned grounds in periglacial regions on Earth
is based on the process of frost heave, where repeated freeze-thawing of water leads to the deformation of the
ground (cryoturbation) (Warburton, 2013). On today’s Mars, the climatic conditions are not favorable for
extensive freeze-thawing processes (Barrett et al., 2017). However, vast quantities of ground ice enable frost
heave processes through dry-cryoturbation. In addition, thermoturbation processes in ice-cemented soils are
also assumed to be responsible for polygonated ground formation (Levy et al., 2009). Thereby, temperature
differences lead to extensional and compressional forces in the salt cemented soil and can thus facilitate cracking
and turbation processes. Patterned grounds are also observed in the hyper-arid Atacama Desert where
cryoturbation can be excluded due to the high temperatures and thus polygonated soils do not necessarily
indicate ground water. These features are assumed to have formed by a combination of thermoturbation and
haloturbation where repeated precipitation and dissolution of salts deform the ground (Buck et al. 2006). Hence,
in addition to periglacial processes (frost heave), patterned ground formation processes in hot hyper-arid regions
(salt heave) should be considered for Mars as well.
Therefore, we investigate the morphometric build-up of patterned grounds with photogrammetry techniques in
combination with physicochemical soil analyses in the hyper-arid Atacama Desert and in periglacial Spitsbergen
for comparing our results with those from Mars. Based on these data we aim to derive patterned ground
formation processes and evaluate their habitability. A better understanding of patterned ground formation will
also improve our understanding of the landscape evolution of the Atacama Desert, as well as for Mars and their
potential past and present habitability.
References:
Barrett, A. M., Balme, M. R., Patel, M. R., & Hagermann, A. (2017). Clastic patterned ground in Lomonosov
crater, Mars: examining fracture
controlled formation mechanisms. Icarus, 295, 125-139. doi:10.1016/j.icarus.2017.06.008
Buck, B. J., Rech, J., Howell, M., Prellwitz, J., & A.L, B. (2006). A New Formation Process for Patterned Ground,
Atacama Desert, Chile.
Geological Society of America Abstracts with Programs, v. 38(7), p.520.
Hallet, B. (2013). Stone circles: form and soil kinematics. Philos Trans A Math Phys Eng Sci, 371(2004).
doi:10.1098/rsta.2012.0357
Levy, J. S., Head, J. W., & Marchant, D. R. (2009). Cold and dry processes in the Martian Arctic:
Geomorphic observations at the Phoenix landing site and comparisons with terrestrial cold
desert landforms. Geophysical Research Letters, 36(21). doi:10.1029/2009gl040634
Warburton, J. (2013). 8.19 Patterned Ground and Polygons. In Treatise on Geomorphology (pp. 298-312).
Washburn, A. (1973). Periglacial Processes and Environments. In (pp. 49 -162).
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A New Formation Process for Patterned Ground
  • B J Buck
  • J Rech
  • M Howell
  • J Prellwitz
Buck, B. J., Rech, J., Howell, M., Prellwitz, J., & A.L, B. (2006). A New Formation Process for Patterned Ground, Atacama Desert, Chile. Geological Society of America Abstracts with Programs, v. 38(7), p.520.