Several laboratory analyzes of Antarctic minerals offer a better understanding of Mars

The results of multiple and complementary laboratory analyzes of minerals found in Antarctic material samples could give scientists a better understanding of the surface and subsurface environment of Mars, and indicate the locations of locations of potentially habitable subsurface areas, according to a new paper by Planetary Science Institute research scientist Elizabeth C. Sklute.

Samples of intermittent brine discharge at Blood Falls, at the terminus of Taylor Glacier, Antarctica, were collected by Jill Mikucki of the University of Tennessee at Knoxville over two field seasons. The brine flows from a groundwater body that has been isolated for perhaps thousands of years. The brine stream deposits materials that [is the] surface manifestation of a subterranean environment that supports a thriving community of microbial life. Initially, the brine is clear, but the deposits redden over time on the surface, giving Blood Falls its name. These surface grab samples were tested at Sklute’s laboratory using Fourier Transform Infrared, Raman, Visible Near Infrared, and Mössbauer spectroscopy. Samples were then characterized using microprobe and inductively coupled plasma optical emission spectroscopy for chemistry, and X-ray diffraction, scanning electron microscopy and microscopy transmission electronics for mineralogy, crystallography and chemistry.

“We took dry samples and analyzed them by illuminating them with different wavelengths. Each wavelength of light causes the bonds and atoms in a sample to react in a different way. Using them all together it allows us to understand what’s there,” said Sklute, lead author of “A Multi-Technique Analysis of Surface Materials From Blood Falls, Antarctica” which appears in Frontiers of astronomy and space science.

“We take each of these little pieces of information and we glue them together to form a whole picture because one technique can be very good at telling you if certain things are there and another technique can completely miss it, just because the bonds or the atoms let’s not react to those energies,” Sklute said. “These results highlight the strengths and weaknesses of different analytical methods and highlight the need for multiple complementary techniques to illuminate the complex mineralogy of this location.

“By combining these techniques, we determined the detailed mineralogical assemblage of this Mars-like site and learned that the deposit is primarily carbonates and that the red color of Bloody Falls comes from the oxidation of dissolved ferrous ions ( Fe2+) when exposed. Instead of forming ferric minerals (Fe3+), which usually happens on Earth, this brine turns into amorphous nanospheres (with no long-range structure) containing iron and a bunch of other elements, like chlorine and sodium. Amorphous materials have been found to be ubiquitous in the Gale crater on Mars by the Curiosity rover,” Sklute said. “To date, we have not been able to determine what is composed of amorphous material on Mars. Finding what could be a similar material in a natural environment on Earth is really exciting.

“We’re not saying it’s a biosignature because it’s not produced by the microbes but rather by the chemistry where the microbes live. It does, however, give us a roadmap for somewhere to look on a another frozen world,” Sklute said. .

“The method we used in this study will also provide a powerful tool to help us understand how things can change over time if they return from another planet. It helps us understand the variability of the phases that are really in below the detection limit of most common techniques,” Sklute said.

PSI Senior Scientist Dr. Darby Dyar is a co-author of the paper.