Microbialites at Gusev Crater, Mars.

Abstract

The Mars Exploration Rover Spirit investigated plains at Gusev crater, where sedimentary rocks are present. The Spirit rover's Athena morphological investigation shows microstructures organized in intertwined filaments of microspherules: a texture we have also found on samples of terrestrial stromatolites and other microbialites. We performed a quantitative image analysis to compare 45 microbialites samplings with 50 rover's ones (approximately 25,000/20,000 microstructures). Contours were extracted and morphometric indexes obtained: geometric and algorithmic complexities, entropy, tortuosity, minimum and maximum diameters. Terrestrial and Martian textures resulted multifractals, while terrestrial abiogenic minerals showed a simple fractal structure. Mean values and confidence intervals from the Martian images overlapped perfectly with those from terrestrial samples. The probability of this occurring by chance was less than 1/2 8 , p<0.004. Our work show the presumptive evidence of microbialites in the Martian outcroppings explored by "Spirit", confirming our previous results concerning the Martian outcroppings explored by Opportunity at Meridiani Planum: unicellular life was widespread on the ancient Mars.

Seeding the Solar System with Life: Mars, Venus, Earth, Moon, Protoplanets

“…Subsequently, in 2009, Rizzo andCantasano (2009, 2017) re-ported evidence of fossilized microbialites based on a detailed examination of Martian sediments resembling stromatolites. Additional evidence of microbialites, microbial mats, thrombolites and stromatolites were subsequently provided by numerous investigators (Bianciardi et al 2014(Bianciardi et al , 2015Joseph et al 2019Joseph et al , 2020aRuff and Farmer 2016;Small 2015).…”

Searching for Life on Mars: the Role of Chaos

“…The fractal analysis of the Athena images shot by the Opportunity rover, analyzing 15,000 microstructures, showed fractal parameters that were overlapping the ones of terrestrial biogenic microbialites: the probability of this occurring by chance was less than 1/2 8 , p<0.004 (Table 2) (while, abiogenic pseudostromatolites presented morphometric indexes statistically different from the ones of biogenic stromatolites) (Bianciardi et al 2014). Analogous results were obtained analyzing 20,000 microstructures shot by the Spirit rover (Bianciardi et. al 2015).…”

Why should geological criteria used on Earth not be valid also for Mars? Evidence of possible microbialites and algae in extinct Martian lakes

“…7 in Rizzo and Cantasano, 2017). Other structures of 'constructive' type that on Earth are formed by continuous, biologically-related building up that assume peculiar shapes at different scales (columnar, spherical, filamentous, lamp-or donut-shaped) have a counterpart on Mars (Bianciardi et al, 2015;Rizzo and Cantasano, 2017). An example is the spherical concretions of hematite (the well-known 'blueberries') often cited as evidence for sea-lacustrine environments on Mars (Moore, 2004).…”