Bone Diagenesis

Diagenesis

postmortem alterations in the physical, chemical, and microstructural composition of bone following its deposition in the environment

• Destruction

• Fossilization

Destruction

bone decay

Fossilization

minerals replace organic material of bone

• minerals retain the shape of bone

• very specific process

Main Diegenetic Processes

1. Accelerated collagen hydrolysis

2. Catastrophic dissolution

3. Microbial bioerosion

Accelerated Collagen Hydrolysis

chemical degradation of collagen

Catastrophic Dissolution

chemical degradation of both collagen and hydroxyapatite

Microbial Bioerosion

biological degradation of collagen and hydroxyapatite

• Most common form of diagenesis

• invasive organisms degrade bone proteins

• create micro-foci of destruction

Micro-Foci of Destruction

characteristic tunnels in the internal microstructure of the bone

Wedl Tunneling

associated with blue-green algae destruction in aquatic environments

• clue that body was immersed in water that contains algae

Non-Wedl Microfocal Destruction (MFD) Tunneling

Found in archaeological bone from terrestrial contexts

Methods

• Thin Section Light Microscopy

  • thin cross section of bone

  • cross section is mounted on a slide and examined

• Scanning Electron Microscopy

• Micro CT Scans

Enteric Gut Bacteria

death → mucosal membranes confining enteric bacteria break down → bacteria migrates via circulatory system within hours → involved in initial putrefaction stages of decomposition → bacteria gain access to bone via haversian system → infiltrate bone and impact osteocytes

When is osteolytic microbiome obtained?

• after birth

  • bacterial bioerosion not present in stillborns; present in live births