To detect life or its remnants in opaque environments, such as inside soils, rocks, or loose mineral matrices, is one of the most challenging of problems that will face scientists. It is a major challenge both for in situ analyses (which rocks do we choose for bring from Mars to Earth, and which may have life that could be detected in situ?), and for returned samples (how can we certify samples as safe, or recommend those that should be examined further?).

When conditions get extreme much of the life moves from the clement surface environment into the pores and more clement environments inside of rocks, minerals and soils. Once encased in their lithic homes, these microbes become nearly impossible to study by standard techniques because of the opacity of the rocks. It is this problem that we propose to address in this presentation.

We were able to detect layers of microorganisms inside rocks from Dry Valley (Antarctica). Also we imaged fossilized samples of biological origin in ancient rocks. With increased resolution to 2-5 micron we hope to apply microtomography for detection thin layers of biofilms on rock surfaces.