In-Situ Multispectral Investigation of the Biogeochemistry of the Geldingadalir Lava Field

Scientific payload demonstration in volcanic environments for astrobiological research understanding microbial colonization of fresh basalt. The volcanic eruption in at Geldingadalir (Iceland) in 2021 is an ideal analog site for studying the biogeochemistry of volcanism on other planetary bodies, both those with active (e.g. Io) and extinct (e.g. Mars) volcanic systems. The recent eruption enables comparative studies between the "fresh" lava field at Geldingadalir and older, inactive lava fields present throughout Iceland. Studying these systems provides insight into (1) the conditions necessary for microorganisms or other biotic materials to colonize barren environments and (2) how life transforms its environment over time. These investigations, while interesting in their own right for characterizing the biogeochemical diversity of Iceland's landscapes, have implications beyond Earth in the search for extant or extinct life in our solar system. To simulate planetary exploration missions, we deployed a suite of four handheld, low-SWaP (size, weight, and power), ruggedized spectroscopic instruments to enable in-situ investigation of the lava fields. We deployed a gamma ray spectrometer and laser induced breakdown spectroscopy (LIBS) probe for macroscopic and microscopic (respectively) assessment of the elemental composition of the natural samples; we used an ultraviolet (UV) fluorescence imager to investigate organic signatures present on the natural surfaces; and finally, we used a near-infrared (NIR) reflectance spectrometer for determining mineralogy and identifying hydrated bonding structures. These complementary measurement techniques enable a wholistic study of a samples' biogeochemistry and have a direct path for mission infusion in planetary science, as various embodiments of these spectroscopic techniques have been used to study planetary surfaces for decades. We collected co-registered spectroscopic measurements with all four instruments on several samples throughout the Geldingadalir lava field and at a control (i.e. inactive) field nearby. Additionally, we surveyed >10 surface and subsurface features throughout the lava field with one or more of the instruments. At the conclusion of this field campaign, we had collected >1000 UV fluorescence images, 10s of NIR reflectance and LIBS spectra, and >10 gamma ray measurements. Along with this, samples from the fresh and inactive lava fields were taken back to the lab for further investigation of microbial diversity using laboratory instrumentation.

Abstract of an Oral Presentation or a Poster

(15) géologie