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Abstract EANA2025-93


Investigating Biogenicity in the 3.33 Ga Josefsdal Chert using Space-Prototype and Laboratory-Scale Laser Mass Spectrometry

Salome Gruchola (1), Andreas Riedo (1,2), Luca N. Knecht (1), Peter Keresztes Schmidt (1), Marek Tulej (1), Frances Westall (3), and Peter Wurz (1,2)
(1) Physics Institute, Space Research and Planetary Sciences, University of Bern, Switzerland (2) NCCR PlanetS, University of Bern, Switzerland (3) CNRS Centre de Biophysique Moléculaire, Orléans, France


In this contribution, we present the chemical composition analysis of the 3.33 Ga Josefsdal Chert from the Barberton Greenstone Belt, South Africa, using Laser Ablation Ionization Mass Spectrometry (LIMS). Two LIMS instruments were employed to investigate the sample’s biogenicity through morphology and element composition analyses: a spaceflight prototype (LMS, [1]) and a laboratory-scale instrument (LMS-GT, [2]). LMS was developed for in situ element, isotope, and organics composition analyses of solids on the surfaces of planetary bodies and moons within our Solar System, while LMS-GT, less constrained by size and design complexity, offers enhanced performance by means of e.g., mass resolving power and the potential for cross-validation of LIMS chemical data.

The investigated carbonaceous chert shows evidence of hydrothermal and volcanic activity, with erosional features suggesting deposition in shallow water environments [3]. The high abundance of carbonaceous matter (CM) is interpreted as a potential remnant of microbial communities entrapped in sediments and preserved during diagenesis. 2D element mapping of the sample surfaces performed with both LIMS instruments revealed the distribution of CM throughout the chert, and a close association with volcanic ash and dust layers was found. CM was identified in various forms, including wavy laminations, carbonaceous clots, and irregular coatings on volcanic clasts. The CHNOPS elements, the six most important elements that are found in various combinations in most biomolecules, were detected simultaneously in several locations within the CM. Additionally, transition metals, which are essential for the metabolic functions of anaerobic prokaryotic lifeforms [4], were identified using the high-resolution LMS-GT instrument and were found to spatially correlate with the CM. Positive detections of transition metals using the space-prototype LMS instrument were achieved through matching of characteristic isotope peak patterns. These observations support a biogenic origin of the CM within the Josefsdal Chert.

These results will be discussed in the context of early Earth origin-of-life studies as well as in the broader framework of the search for extraterrestrial life using laboratory-scale and space-prototype LIMS instrumentation, respectively. The dual-instrument approach highlights the potential synergy between LIMS systems for both in situ planetary exploration and future sample return missions.

 

[1] A. Riedo, et al., 2013, J. Mass Spectrom., 48, 1 - 15, doi:10.1002/jms.3104.

[2] R. Wiesendanger, et al., 2019, J. Anal. At. Spectrom., 34, 2061 - 2073, doi: 10.1039/C9JA00235A.

[3] F. Westall, et al., 2015, Geology, 43 (7): 615–618. doi: 10.1130/G36646.1.

[4] K. Hickman-Lewis, et al., 2020, Sci Rep 10, 4965, doi: 10.1038/s41598-020-61774-w.