Chapter 5

taphonomy

the study of the processes by which organic remains pass from the biosphere into the lithosphere as the result of geological and biological processes

bones can be modified by .. and factors

animals - physical

animal factors

trampling, gnawing, digestion, movement of remains

physical processes

water transport, weathering, burial, rockfall, freezing and thawing, root activity, other environmental factors

animal and physical processes can cause

disarticulation (skeleton falling apart), scattering of bones, changes to the bone surface that may resemble injuries or tools marks

trampling - can create marks on bones that look very similar to

cut marks made by tools

animal chewing and trampling can cause .. fractures

spiral

weathering

taphonomic process that reflects how bone responds to environmental conditions such as sunlight, soil and exposure

methode van Behrensmeyer - 6 stages

0 = fresh bone with no weathering / 1 = initial cracking / 2 = flaking and loss of the outer bone layers / 3 = development of a rough, fibrous texture as outer layers are removed / 4 = deep weathering with splintering and penetration into inner cavities / 5 = severe deterioration, with the bone falling apart and losing its original shape

taphonomic analysis in forensic cases is used for

estimating PMI / reconstructing the environment / reconstructing postmortem events / distinguishing evidence of foul play from alterations caused by natural processes

human remains differ from animal remains because human bodies are often affected by cultural practices after death, such as

embalming - cremation or burning - burial - coffin enclosure - other mortuary treatments

the rate of decomposition is highy variable and influenced by numerous factors, including

temperature and rainfall / clothing and burial conditions / burial depth / animal scavenging and disarticulation / perimortem trauma / body weight / general environmental conditions

.. can result in skeletonization within as little as two weeks

tropical enviroments

… may promote mummification and long-term soft tissue preservation

dry enviroments

.. may produce adipocere, which can preserve remains for extended periods

wet environments

chemical compounds produced during decomposition, such as … and …, can accumulate in underlying soil and may be used to estimate PMI under certain conditions

volatile fatty acids - other ions

… indicate exposure to salt water

barnacles

… suggest a moist, shaded environment

green algae staining

bone bleaching

reflects prolonged sun exposure - salt water can produce similar effects

weathering cracks may look like …

blunt force trauma fractures

… causing black discoloration that can mimic burning

fungal activity

carnivore tooth marks can resemble …

sharp force trauma