10.2 Fossil Preservation and Taphonomy

Fossil preservation and taphonomy are crucial for understanding our ancient past. These fields study what happens to organisms after death, from burial to fossilization. They help us interpret the fossil record, reconstruct past environments, and understand preservation biases.

Various modes of preservation exist, from freezing to permineralization. Biological, physical, and chemical processes alter fossil remains over time. By analyzing fossil conditions, sedimentary context, and taphonomic signatures, we can piece together the history of fossil assemblages and gain insights into ancient life.

Fossil Preservation and Taphonomy

Definition and importance of taphonomy

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  1.3 Types of fossil preservation | Digital Atlas of Ancient Life View original

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  Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi ... View original

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  1.3 Types of fossil preservation | Digital Atlas of Ancient Life View original

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  1.3 Types of fossil preservation | Digital Atlas of Ancient Life View original

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  Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi ... View original

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  1.3 Types of fossil preservation | Digital Atlas of Ancient Life View original

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  Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi ... View original

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  1.3 Types of fossil preservation | Digital Atlas of Ancient Life View original

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  1.3 Types of fossil preservation | Digital Atlas of Ancient Life View original

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  Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi ... View original

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• Taphonomy studies processes affecting organisms after death encompasses burial decay fossilization and preservation
• Significance in paleoanthropology helps understand biases in fossil record aids reconstructing past environments and ecosystems
• Provides context for interpreting fossil assemblages informs about preservation potential of different tissues and organisms (bones vs soft tissues)
• Crucial for accurate dating and environmental reconstruction influences interpretation of evolutionary trends

Modes of fossil preservation

• Unaltered preservation freezing preserves entire organisms (woolly mammoths) amber inclusions trap small organisms (insects)
• Permineralization mineral-rich groundwater fills pore spaces common in bones and wood creates detailed internal structure
• Replacement original material replaced by minerals petrification turns wood to stone pyritization replaces with iron sulfide
• Carbonization organic material reduced to carbon film preserves delicate structures (plant leaves fish scales)
• Molds and casts external molds leave impressions in sediment internal molds fill cavities casts form 3D replicas

Processes altering fossil remains

• Biological processes scavenging alters bone assemblages microbial decomposition breaks down soft tissues bioturbation mixes sediments
• Physical processes weathering erodes exposed fossils transport sorts remains by size and density compaction distorts shapes
• Chemical processes dissolution removes soluble minerals diagenesis alters chemical composition permineralization fills pores
• Environmental factors pH levels affect preservation temperature fluctuations cause expansion and contraction water and oxygen influence decay rates

Interpretation of fossil assemblage histories

• Analyze fossil condition articulation indicates rapid burial weathering stages show exposure time fragmentation patterns reveal transport
• Examine sedimentary context depositional environment influences preservation stratigraphic position provides temporal context
• Identify taphonomic signatures tooth marks indicate scavenging cut marks suggest tool use orientation of bones shows water flow direction
• Assess preservation biases hard tissues (teeth bones) overrepresented juveniles and small species often underrepresented
• Consider time-averaging mixing of fossils from different periods affects paleoecological interpretations requires careful analysis
• Evaluate spatial distribution clustering may indicate mass mortality events association with artifacts suggests human activity