Taphonomic History: Bone Exposure & Soft Tissue Modification

• Taphonomic history encompasses the events that affect organic remains after death, from the initial death event to the point of discovery and collection.

Actual Death Event

• This is the starting point of taphonomic history.
• Details surrounding the death event can influence subsequent taphonomic processes.
• Cause of death, location of death, and immediate environment all play a role.

Interval of Bone Exposure Through Modification of Soft Tissue

• This stage involves the decomposition of soft tissues, which exposes the underlying bones.
• The rate of soft tissue modification is affected by various factors.
• Temperature: Higher temperatures generally accelerate decomposition.
• Humidity: Moisture levels influence microbial activity and insect colonization.
• Scavenging: Animal activity can significantly alter the remains and scatter bones.
• Insect Activity: Insects, such as flies and beetles, contribute to soft tissue removal.
• Microbial Activity: Bacteria and fungi break down organic matter.
• Burial: If the body is buried, decomposition rates can be altered depending on soil composition, depth, and oxygen availability.
• This interval is critical because the condition of the bones at this stage can influence later taphonomic modifications.

Interval of Bone Modification

• Once bones are exposed, they undergo further modifications due to various factors:
• Weathering:
  • Sun exposure can cause bleaching and cracking.
  • Freeze-thaw cycles can lead to exfoliation of the outer bone layers.
  • Wet-dry cycles can cause warping and cracking.
• Soil Chemistry:
  • Acidic soils can dissolve bone minerals, leading to degradation.
  • Alkaline soils can preserve bone but may also cause surface alterations.
• Root Etching:
  • Plant roots can grow on and into bones, leaving characteristic etching patterns.
• Animal Modification:
  • Rodents gnaw on bones for calcium and to sharpen their teeth, leaving distinctive marks.
  • Carnivores may chew on bones for marrow, causing fragmentation and punctures.
• Trampling:
  • The movement of animals or humans over bones can cause breakage and scattering.
• Water Transport:
  • Bones can be transported by water, leading to abrasion and dispersal.
• Fire:
  • Exposure to fire can cause bones to become calcined, carbonized, or blackened, depending on the temperature and duration of exposure.
• Human Modification:
  • Cut marks from butchering or dismemberment.
  • Modifications from tool use.
  • Intentional burial or scattering.
• The accumulation of these modifications provides insights into the postmortem history of the remains.

Point of Discovery and Collection

• This final stage marks the end of active taphonomic processes and the beginning of analysis.
• The context of discovery is crucial for interpreting the taphonomic history.
• Location: Documenting the precise location of the remains is essential.
• Position: The spatial arrangement of bones can provide clues about taphonomic events.
• Associated artifacts: Any artifacts found with the remains can offer additional context.
• Collection methods: Proper techniques are necessary to avoid damaging the remains or altering the evidence.
• Documentation: Detailed notes, photographs, and maps are essential for preserving information.
• The condition of the remains at the point of discovery reflects the cumulative effects of all previous taphonomic processes.