Soil Staining
Definition
The dark, organo-mineral discolouration of soil directly surrounding a decomposing body, caused by leaching of fats, decomposition fluids, and breakdown products. It persists in the soil matrix long after the body itself has skeletonised and can outline a body plan where bones have dissolved.
- Cause
- Leaching of fats, decomposition fluids and breakdown products into surrounding soil
- Persistence
- Outlasts the body, remains visible after full skeletonisation
- Use
- Can outline a body plan where bones themselves have dissolved
- Field
- Burial taphonomy and clandestine grave excavation
Common questions
How is soil staining located during excavation?+
Excavators look for a discoloured, often darker or greasy-textured zone against the surrounding soil matrix, usually mapped and photographed in plan view as digging proceeds layer by layer, since the stain can extend beyond where visible skeletal material remains.
Why does soil staining outlast skeletal remains?+
Fats and decomposition fluids bind to soil minerals and organic matter, forming compounds that resist further breakdown far longer than bone survives in acidic or otherwise unfavourable burial soils, so the stain can be the only surviving evidence of body position.
Related terms
- Adipocere
- A waxy, soap-like substance formed by saponification of body fat under anaerobic, wet, cool-to-moderate conditions. Replaces unsaturated fatty acids with saturated palmitic...
- Autolysis
- Self-digestion of cells after death caused by the release of lysosomal enzymes. No microbial involvement is required. Autolysis begins within minutes of...
- Grave Wax
- A synonym for adipocere in field parlance, though strictly the term refers to the solid end-product of long-run saponification rather than the...
- Putrefaction
- Decomposition of tissues by microorganisms, principally anaerobic bacteria from the gastrointestinal tract. Products include hydrogen sulphide, methane, ammonia, and putrescine, which cause...
- Taphonomy
- The systematic modification of bone by environmental processes after death, operating over the burial or exposure interval. Includes weathering, soil staining, sun...