Evidence of mud volcanism due to the rapid compaction of martian tsunami deposits in southeastern Acidalia Planitia, Mars

Abstract

Thumbprint terrain was first recognized in Viking Orbiter data and described as sets of alternating continuous parallel ridges and depressions up to several tens of kilometres in length, with high and low albedo respectively. We performed a geomorphological analysis of these features using both Context Camera and High Resolution Imaging Science Experiment images, as well as topographic profiles based on Mars Orbiter Laser Altimeter data, with the aim to provide an origin for thumbprint terrain and constrain the geological evolution of southeastern Acidalia Planitia. The identification of runup lobate deposits, coupled with the putative presence of a Late Hesperian ocean in the northern lowlands, led to speculations that evidence of tsunamis may be present in the geologic record of the area. There are several hypotheses that have been proposed previously to explain the origin of thumbprint terrain and include ice-related, volcanicrelated, liquefaction and mud-volcanism driven processes. However, a tsunami-related origin provides a strong geological framework for the energy required for the associated lobes to flow uphill and leaving peripheral termination ridges as a result of viscosity. Numerical simulations indicate that-prior to their emplacement-the lobes sustained high velocities, thereby lending further support to the tsunami hypothesis and their origin from the Lomonosov crater impact. Wave interference patterns, formed during the propagation of the tsunamis over and around prominent topography, likely explain the thumbprint terrain spatial arrangement. The thumbprint terrain sedimentary cones are, herein, considered mud volcanoes related to a tsunami that occurred in southeastern Acidalia Planitia.

Megatsunamis and microbial life on early Mars

“…Thumbprint terrains are part of the geomorphological features of the Martian megatsunamis, discovered by geomorphological mapping, CTX and THEMIS imaging in the southeast of the Acidalia Planitia (northwest of the Arabia Terra), and the Chryse Planitia. Due to the high albedo of thumbprint terrains, they appear to be coarse-grained and made of sand, gravel and rock fragments (Costard et al, 2017;Di Pietro et al, 2021) (Fig. 3).…”

“…The first megatsunami caused by a collision occurred in a liquid ocean, and caused the boulder rocks to scatter on the surface of Mars. Nevertheless, the second megatsunami occurred in a frozen ocean (due to the cooling of the Martian climate), scattering ice-rich lobes on the surface of the Red Planet (Drake, 2016;Rodriguez et al, 2016;Sumner, 2016;Di Pietro et al, 2021). Some impact craters on the northern plains, such as the Lyot crater (48°33 ′ 42.7 ′′ N, 18°12 ′ 46.7 ′′ E), have the ice-rich ejecta from the second megatsunami (Di Pietro et al, 2021).…”

“…Studies of the geology of Mars have suggested the possibility of a shallow and vast ocean in the past (Mahaney et al, 2010;Iijima et al, 2014;Billings, 2016;Costard et al, 2017Costard et al, , 2019Di Pietro et al, 2021).…”

“…The collision of these large objects in the northern palaeo-ocean of Mars has certainly caused megatsunamis, and some researchers claim that there is evidence of tsunami-induced sediments on the surface (Billings, 2016;Witze, 2016;Costard et al, 2017Costard et al, , 2019Stanley, 2020;Di Pietro et al, 2021). Because tsunami waves on Earth affect marine microbial communities, the effect of Martian megatsunamis on the ancient microbial life on this planet is not unexpected.…”

High Resolution Apparent Thermal Inertia Mapping on Mars

“…Thirdly, Di Pietro et al [62] made a detailed thermal inertia map using differential apparent thermal inertia technique on a selected portion of the studied area (thumbprint terrains in Acidalia Planitia) to give information on the particle sizes and more generally, thermophysical properties of the soil. After analysing all the datasets (differential apparent thermal inertia technique, Context Camera, High-Resolution Imaging Science Experiment images, and topographic profiles based on Mars Orbiter Laser Al-timeter) they supported the tsunami-driven mud-volcanoes hypothesis in the study area.…”