Controls on authigenic mineralization in experimental Ediacara-style preservation

Area of Science:

• Paleontology
• Geochemistry
• Sedimentology

Background:

• Ediacara-style preservation represents the earliest evidence of complex macroscopic life.
• The fossilization mechanisms of these soft-bodied organisms in siliciclastic deposits remain debated.
• This preservation occurs in various sandstone facies, from quartzose to clay-rich types.

Purpose of the Study:

• To investigate the mechanisms behind Ediacara-style preservation.
• To test the role of dissolved silica and mineral substrates in fossilization.
• To understand the preservation potential of soft tissues in early Earth environments.

Main Methods:

• Experimental simulation using diverse mineral substrates (quartz, kaolinite, iron oxides).
• Testing with various soft-bodied organisms (microalgae, cyanobacteria, invertebrates).
• Varying dissolved silica (DSi) concentrations to mimic Ediacaran seawater conditions (0.5–2.0 mM).

Main Results:

• Observed extensive amorphous silica and authigenic clay coatings on organic substrates.
• Documented a progressive drawdown of dissolved silica in experimental solutions.
• Demonstrated rapid preservation of soft tissues under varied conditions.

Conclusions:

• Silicate mineral precipitation, influenced by seawater DSi, rapidly preserves soft tissues.
• Substrate composition and DSi levels are key factors in Ediacara-style fossilization.
• These interactions provide plausible mechanisms for the preservation of early complex ecosystems.