Atomic force microscopy of Precambrian microscopic fossils

Area of Science:

• Paleontology
• Geochemistry
• Materials Science

Background:

• Organic-walled microfossils, such as sphaeromorph acritarchs, offer insights into Precambrian life.
• Understanding their fine structure is crucial for paleobiological and geochemical interpretations.
• Previous studies lacked high-resolution nanoscale imaging of these ancient organic structures.

Purpose of the Study:

• To analyze the submicron-scale structure of 650-million-year-old acritarch fossils.
• To determine the composition and arrangement of organic material within fossil walls.
• To explore the utility of advanced microscopy and spectroscopy for fossil analysis.

Main Methods:

• Application of Atomic Force Microscopy (AFM) for high-resolution imaging of fossil surfaces.
• Utilizing laser-Raman spectroscopy for in-situ chemical analysis of individual microfossil specimens.
• Correlating AFM topographical data with spectroscopic chemical signatures.

Main Results:

• AFM imaging revealed fossil walls composed of stacked, angular platelets approximately 200 nm in size.
• Laser-Raman spectroscopy confirmed these platelets are made of polycyclic aromatic kerogen.
• The study successfully elucidated the nanoscale architecture of the acritarchs' organic walls.

Conclusions:

• AFM and laser-Raman spectroscopy are effective tools for detailed microfossil analysis.
• The findings provide insights into the geochemical maturation and preservation mechanisms of ancient organic matter.
• This methodology can aid in distinguishing genuine microfossils from pseudofossils.