What does a forensic archaeologist do?
Archaeologists have training in a variety of skills to help them locate and excavate grave sites. Whether these are modern or archaeological in nature, the techniques for the location and excavation of buried human remains are broadly the same. These skills include:
1) Expertise in landscapes and in identifying and interpreting changes in vegetation or soils that may be linked to disturbance associated with a clandestine burial. For example, see the differences in vegetation in the images below. In the top image the soil has essentially been aerated during grave construction and the presence of the body has provided nutrients to the soil, resulting in greater vegetation growth, as well as the presence of colonising plants (e.g. weeds). In the bottom image rocks were placed over the body and this has diminished the plant growth immediately above them.
2) Experience of conducting or interpreting aerial surveys and field walking surveys in order to identify potential sites of interest. For example, differences in vegetation associated with a grave site.
3) A good understanding of geology and soil and the feasibility of burial within the area, as well as the likely effects of the burial environment on human remains.
4) A good knowledge of the different techniques of remote sensing and which geophysical methods are likely to yield the best results in a given terrain (we’ll look at this in Week 2).
5) Expertise in the time-consuming and laborious process of carefully excavating and recording a site. Excavation is destructive and information lost at this point is irretrievable.
Most police and crime scene investigators are not trained in these techniques and it is therefore essential that they work alongside archaeologists and have an understanding of the importance of these methods
What is Stratigraphy?
An understanding of stratigraphy is fundamental to archaeological excavation. Stratigraphy refers to the layered deposition of soil and materials over time (both natural and made by humans). The basic principle is that lower layers are older and the upper layers were deposited more recently. Any objects or features within the layers can then be dated relative to those above and below. Archaeologists can examine the edges of features made by humans such as ditches, post-holes or graves to see which layers they disturb and which they are overlain by. This can help to establish a relative chronology.
Stratigraphic layers highlighting the different deposits and objects buried in relation to each other
In areas with complex stratigraphy (particularly in urban environments) archaeological skills are extremely important for establishing relationships between different soil layers and objects/bodies within them. This is vital for establishing a relative time sequence of events (see Post-Mortem interval). Archaeologists are particularly good at differentiating between subtleties in soil types to reveal different layers. Archaeological excavation involves what’s referred to as single context recording, whereby each layer is removed and recorded sequentially so that the archaeologist is effectively moving backwards in time as they dig.
Archaeologists are crucial for interpreting and distinguishing between natural and cultural events relating to site formation processes. For example, was a body buried within a deliberate grave cut? If so, this indicates disposal by another person. Or was the body simply laying in a natural depression? If so, this may indicate death through exposure and natural causes. These skills are important, therefore, for differentiating between criminal and natural activity and interpreting the site. In Week 2 will will explore the importance of archaeological techniques of excavation.
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