DETECTION OF PAST BIOLOGICAL ACTIVITY IN MARTIAN SEDIMENTS UNDER CATHODOLUMINESCENCE

摘要

The cathodoluminescence (CL) consists in irradiating the sample with an electron beam of energy range 10 to 20 keV. This process induces a luminescence (in the visible wave length); its spectrum analysis gives data on the mineralogical composition; images at different scales give data on the growing process. Looking for a fossil biological activity may be approached by the search of cells or fossil cells, but also by the study of the results of their activity and their interface with the mineralogical environment. Such bio-sedimentations are known among the oldest terrestrial fossils and testify of the earliest terrestrial bioactivity. A discovery of such bio-sedimentations on the Martian surface would be of a prime interest for the exobiology concept. CL seems to be such a relevant method, allowing to reach these analytic goals and fitting well with robotics facilities. It could be an optional subsystem to any optical microscopic experiment using an autonomous "electron lamp".