Throughout biologic history, microbe-level life has been ubiquitous, abundant, metabolically diverse, and for the earliest (Precambrian) seven-eighths of geological time, biotically predominant. Understanding of this earliest stage of biologic development has progressed markedly in past decades, but problems of interpreting the preserved fossil record still remain. Perhaps foremost among such problems is the difficulty of unambiguously distinguishing true microbial biologic remnants from nonbiologic (e.g., mineralic) look-alikes. This problem can be addressed by demonstrating in objects claimed to be microscopic fossils a one-to-one correlation, in three dimensions and at a micron scale, of preservable "biological morphology" with geochemically altered "biological chemistry." We have now developed two non-destructive, non-intrusive techniques, both new to paleobiology/astrobiology, that meet this need:

1. Confocal laser optical microscopy provides means to image in three dimensions at micron-scale the visible characteristics of organic-walled microscopic fossils in situ; and
2. Laser-Raman spectroscopic imagery provides means to map, in situ and in three dimensions at micron-scale, the distribution of the carbonaceous matter that comprises such fossils, a technique that also provides salient information regarding the geochemical maturity of such carbonaceous (kerogenous) material.

Applicable to samples returned to Earth from other planets, the use of these new techniques can be expected to revolutionize studies of microbial Precambrian life.

Figure 1.