ARCL 228 - MOD 4

What happns to a body after death (long term)

• Become covered in sediment

• After a few years this could be a small amount of Humus/top soil

• After decades, body will be interred in the ground and diagenesis will occur

What is archaeology

Study of past cultures through material culture that survives as part of archaeological record

• largely destructive to the sites

  • When we excavate the site we destroy much of the evidence at that area

    • We must document everything

Archaeological terms

Sediment: dirt

Stratigraphy: study of the structured/texture of the sediments → the layers of the dirt

Stratum: single layer of the soil/rock

Law of superposition

Law that outermost layer of the dirt/soil is the youngest (what’s on top)

Law of Crosscutting

Law that intrusions will be youngest compared to layers A/B

• the layers must be there before the intrusion is able to slice through

Phases of an archaeological investigation

1. Systematic search for sites

• surfaces surveys with transects and/or remote surveys using radar or aerial photography

2. Evaluation of an area for significance

• Digging a pits to determine site boundaries and focus areas, often done to determine if a full scale investigation is required

3. Recovery

• system excavation of the site and collection of associated artifacts to gain knowledge of the culture

4. Interpretation and reporting

• report is generated based on the information gained in previous phases including a site map, interpretations and conclusions

How does archaeology come into forensics

Application of archaeological theory/methods to the resolution of medicolegal issues

Differences between traditional archaeology and forensic archaeology

• traditional can take months to years to complete, forensics must occur much quicker as evidence can be lost/destroyed

• Forensic scenes are generally simpler that traditional scenes

Phase one of forensic archaeology investigation (part 1)

Systematic search

• search for human remains that have either been buried/on surface → grid search

• Line survey (pedestrian search): link arms/walk in straight line, and put down flag each time they see something that could be suspicious

• Helps find evidence that has been dispersed by scavengers

• Cadaver dogs can be used as well

Phase 1 of forensic archaeology investigation (part 2)

Locating burials

• during surface searches we looks for vegetation/soil disturbances

• After burial soil will compress and a depression will form in its shape

• Subsurface probing: sticking probe into ground to detect different soil consistencies as part of a linear search

Using remote sensing/imaging technologies

• resistivity technologies: detect disturbances using electrical current and resistance

• Ground penetrating radar: electromagnetic pulses used to detect disturbance in soil

• Magnetomtry: detects magnetic changes in disturbed soil

• Infrared imaging: shows differences in heat in soil resulting from disturbance

Forensic archaeology investigation: phase 2

Evaluation of an area for significance

• quick → only evaluating whether or not they have a burial

• Extensive photographs

• medicolegal authority must be contacted by the investigators before recovery of body

• Recovery of body will remove evidence in a way that tries to keep context/reconstruction of the events

Forensic archaeology investigation: phase 3

Recovery

• aim to preserve the context/evidence in order to reconstruct the death event

• Includes the deposition and spatial arrangements of body and taphonomic modifications

• If remains are found they will be processed, collected as evidence and brought to lab

How is evidence recovered

Step 1: remove/screene the overburden from the scene and expose the evidence

Step 2: photograph and map all the evidence

Step 3: excavation: exposure/recovery of remains through slow/careful digging

How do we excavate?

Slow removal of the soil surrounding remains layer by layer

• whenever evidence is exposed it must be photographed, mapped then removed

• After remains are removed the base of burial should be swept with metal detector to check for additional evidence

Documentation of burials

Establish a datum: primarily reference point that will remain consistent and can be mapped throughout recovery (like a building)

Documenting scene

• note taking

• Photographs

• Videography

Collecting evidence

Evidence including remains must be packaged

• all must be marked with the date/location of recovery/name of person who packaged it

• Packaging should be paper/soft cardboard

• If bones are burnt and/or very fragile additional precautions might need to be taken, like wrapping remains in foil before packaging/using gelatin to preserve the remains for transport

  • This helps to prevent moulding

Forensic archaeology investigation: phase 4

Interpretation and reporting

• Contact Investigating agency (police coroner)

• Summarizes the methods used and the interpretation of evidence

• Report is completed even if search didn’t find any remains

State of remains as they arrive to lab

• sometimes bones are already clean/dry

• A lot of the time, there is adhering material → leaves/soil

  • When skeletoal processing comes in

  • This is done in a wet lab/autopsy suite

Types of adhering material

Clothing, jewelry, personal items/effects, debris from decomposition sites

Processing the skeleton with mechanical removal of soft tissue

• soft tissue removed mechanically (scalpels)

• Generally we don’t use sharp edges bc it can harm the bone

  • Damage can impact future analysis

• Goal = articulate the skeleton into individual bones

Processing skeleton: maceration

Softening the tissues by soaking bones in warm water, aided by bacterial decomposition in large pots

• different methods have different temps/soak times or add different enzymes detergents and levels of ammonia - generally done multiple times

  • Warm water is more common for adult remains as its much faster to break down

Processing: carrion beetles

Beetles consume remaining soft tissues at any stage of decay with no damage to the bones

• processing time depoends on amount of beetles used and the condition of the remains or amount of soft tissues

• Maintaining colony is time consuming and requires constant feeding

Processing of skeleton using chemicals

• can involve bleach and other chemicals

• Quickly removes soft tissues, useful when trying to perverse bones as well

• But often degrades bone, hazardous to those working with them and more expensive

Reassembling the skeleton

• bones must be reassembled in the correct position and side

• Important for conducting analyses that attempt to estimate identity and examining patterns of trauma

Reassembling skeleton with what

• not usually done with glue (can take apart again if done incorrectly)

• Tape/putty/wax is used to adhere contents together

• Substances should be able to breakdown with solution/water if done incorrectly

Commingling remains

When more than one skeleton is present or the intermixing of skeletal element from more than 1 individual

• common in mass graves

• anthropologists attempt to identify how many bodied are present/seperate the remains into individuals

How we resolve commingling

Step 1: during recovery

• careful documentation of the providence and the remains located

Step 2: creating inventory/labeling specimen

Step 3: sort all elements by type and side

• eg 1 pair of humeri, 2 left humeri, 7 right femurs, 2 left tibias

  • Sorting can tell us about the minimum amount of individuals or most likely number of individuals

  • Take the highest collected element and that is minimum amount of individuals (7 people bc of 7 femurs found)

Calculating minimum number of individuals (MNI)

1. Sort all elements by side and take the hightest number

   1. 1 pair of humeri (2 bones), 2 left humeri, 3 right humeri, 3 left femurs

      1. Sort between left and right for all

      2. The highest number is 4 right humeri

Calculating most likely number of individuals

Formula = [(R+1)(L+1)/(P+1)-1]

• 1 pair of humeri (2 bones), 2 left humeri, 3 right humeri, 3 left femurs and one left tibia

• Pick one bone type and sort into R, L, and pairs

• I choose humeri =

  • MLNI: [(3+1)(2+1)/(1+1)-1]

  • = 6-1=5

  • Most likely number of individuals are 5