Fluvial Transport of Human Crania

Organic staining on bone from exposure to wood and other plant materials

“…A combination of staining agents can affect a single set of remains, which allows an environmental reconstruction as well as the reconstruction of their position within the environment. In circumstances where remains are deposited on the ground surface, bones may display darker staining on the underside from contact with the soil or decomposing organic materials underneath, while displaying lighter colorations on the top from exposure to sunlight (Nawrocki et al 1997;Norris and Owsley 2014;Owsley et al 2014;Pokines 2016;Pokines and Higgs 2015). Even if the color staining from plant growth cannot allow the identification of a particular environment of deposition, certain environments may be excluded from an investigation.…”

“…As the organic material begins to decompose, humic acid leaches out and can leave etchings or shallow grooves, when in direct contact with the bone surface, due to acid decalcification of the bone (Behrensmeyer 1978;Buikstra and Ubelaker 1994;Byers 2011;Courty et al 1989;Dupras and Schultz 2014;Dupras et al 2012;Hall 1997;Nawrocki 2009;Schultz 1997;Schultz et al 2003;White et al 2012). Living organic material, such as moss or algae, that contacts the bone can also stain the bone surface from contact with the plant pigments (Buikstra and Ubelaker 1994;Dupras and Schultz 2014;Dupras et al 2012;Evans 2014;Nawrocki 2009;Nawrocki et al 1997;Pokines 2016). …”

“…Green algal staining suggests that the remains were placed in a moist or shaded environment, while bleaching or pale colorations suggest long-term sun exposure (Dupras and Schultz 2014;Nawrocki 2009;Nawrocki et al 1997;Norris and Owsley 2014;Owsley et al 2014;Pokines 2016;Pokines and Higgs 2015;Ubelaker 1997). A combination of staining agents can affect a single set of remains, which allows an environmental reconstruction as well as the reconstruction of their position within the environment.…”

“…Bones deposited in moist environments have an increased likelihood of algal or moss growth, which can leave greenish staining from pigments found in plants (Dupras and Schultz 2014;Dupras et al 2012;Evans 2014;Nawrocki 2009;Nawrocki et al 1997). Plant matter also can leave etchings or grooves on the bone surface due to the production of humic acid as a plant decays and contacts the bone (Behrensmeyer 1978;Buikstra and Ubelaker 1994;Byers 2011;Courty et al 1989;Dupras and Schultz 2014;Dupras et al 2012;Hall 1997;Nawrocki 2009;Pokines 2016;Schultz 1997;Schultz et al 2003;Ubelaker 1997;White et al 2012).…”

A comparison of surface features on submerged and non-submerged bone using scanning electron microscopy

“…Some work has demonstrated the issues surrounding element dispersal across a body of water, particularly in rivers [9] . Unfortunately, as is often the case with forensic taphonomic research, there are few highly controlled experimental studies which can be used to garner a base-line for changes from which conditions within the forensic context can be inferred.…”