COG3

Identifying Traces of Primitive Life in Ancient Rocks

The early life fossil record is based upon a limited
number of often controversial graphitic microfossils.
The main complication resides in the poor
preservation of organic biosignatures in the
(meta)sedimentary rock record. Biodegradation and
fossilization processes, as well as the increase of
temperature and pressure conditions during
diagenesis and metamorphism inevitably alter the
original biochemical signatures of organic molecules.
Thus, at a certain stage, biogenic and abiotic organics
may become very difficult to distinguish.
During this talk, I will show how combining
characterization of natural samples using advanced
spectroscopic techniques (STXM-based XANES &
Raman microspectroscopies) and simulation of
fossilization processes in the laboratory sheds new
light on the potential preservation of microorganism
molecular biosignatures in ancient rocks.