Volumetric changes of mud on Mars: evidence from laboratory simulations

0579653 - GFÚ 2024 RIV US eng J - Journal Article
Brož, Petr - Krýza, Ondřej - Patočka, V. - Pěnkavová, Věra - Conway, S. J. - Mazzini, A. - Hauber, E. - Sylvest, M. E. - Patel, M. R.
Volumetric changes of mud on Mars: evidence from laboratory simulations.
Journal of Geophysical Research: Planets. Roč. 128, č. 12 (2023), č. článku e2023JE007950. ISSN 2169-9097. E-ISSN 2169-9100
R&D Projects: GA MŠMT(CZ) EF18_053/0016986
Institutional support: RVO:67985530 ; RVO:67985858
Keywords : Mars * mud flow * sedimentary volcanism * viscosity * low pressure environment
OECD category: Geology; Chemical process engineering (UCHP-M)
Impact factor: 4.8, year: 2022
Method of publishing: Limited access
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023JE007950

Subtle mounds have been discovered in the source areas of Martian kilometer-sized flows and on top of summit areas of domes. These features have been suggested to be related to subsurface sediment mobilization, opening questions regarding their formation mechanisms. Previous studies hypothesized that they mark the position of feeder vents through which mud was brought to the surface. Two theories have been proposed: (a) ascent of more viscous mud during the late stage of eruption and (b) expansion of mud within the conduit due to the instability of water under Martian conditions. Here, we present experiments performed inside a low-pressure chamber designed to investigate whether the volume of mud changes when exposed to a Martian atmospheric pressure. Depending on the mud viscosity, we observe a volumetric increase of up to 30% at the Martian average pressure of similar to 6 mbar. The reason is that the low pressure causes instability of the water within the mud, leading to the bubble formation that increases the volume of the mixture. This mechanism bears resemblance to the volumetric changes associated with the degassing of terrestrial lava or mud volcano eruptions caused by a rapid pressure drop. We conclude that the mounds associated with putative Martian sedimentary volcanoes might indeed be explained by volumetric changes in the mud. We also show that mud flows on Mars and elsewhere in the Solar System could behave differently to those found on Earth because mud dynamics are affected by the formation of bubbles in response to the different atmospheric pressures.
Permanent Link: https://hdl.handle.net/11104/0348454


Research data: Zenodo