Measurements of bio-signature in ancient micrometre-sized fossils with a miniature laser mass spectrometer

Searches for the past and present life on the planetary surfaces will be involving multilevel characterisation of the planetary rocks and soils within potentially habitable environments. Some up to three billion years old stromatolites or fossilised bacterial colonies are particularly interesting. They are found on the Earth and thought to be earliest life forms preserved within the terrestrial sedimentary rocks and can be a benchmark for searches of bio-relevant objects on planetary surfaces. By combining the microscope-camera system and mass analyser one can identify micro-fossilised material within the rocks by means of specific morphological details and characteristic chemical composition. We discuss the results of the studies on ancient microfossils obtained by space-born instrumentation, microscope-camera system combined with laser mass spectrometer. Both, the microscope imaging and chemical analyses can be conducted with micrometre spatial resolution. We demonstrate that the morphological record is helpful but not sufficient to identify bio-relevant material. Yet, while combined with elemental and isotope and with help depth profiling method, the compositional analysis can distinguish between abiotic and biological nature of the material. Detection of biosignature in measurements of fossilised materials with a miniature laser ablation ionisation mass analyser.

 

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