A spectroscopic tool for the detection of biocarbonates

In previous laboratory work we have investigated the infrared spectral modifications induced by thermal processing on different terrestrial carbonates,in form of fresh shells and fossils of different ages, whose biotic origin is easily recognizable. The goal was to find a method able to distinguish between biotic and abiotic origin of the samples. In the present work we apply our analysis to problematic carbonate samples, in which there are no clear evidences of controlled or induced biomineralization. This analysis indicates a very likely biotic origin of the aragonite samples under study, in agreement with the conclusion previously reported by some of us who followed a completely different approach based on a complex set of sedimentary, petrographic, geochemical and biochemical analyses. We show that our method is actually reliable for discriminating between biotic and abiotic carbonates, and therefore it is a powerful tool for the search for life on Mars in the next generation of space missions to the planet.