Phytolith taphonomy: a comparison of dry ashing and acid extraction on the breakdown of conjoined phytoliths formed in Triticum durum

Phytolith evidence for hearths and beds in the late Mousterian occupations of Esquilleu cave (Cantabria, Spain)

“…However, the data obtained through RI analysis indicates that the grass phytoliths are not burnt. In addition, the existence of relatively high percentages of multicellular structures suggests that those phytoliths have not been reworked, since these types of structures are fragile and sensitive to mechanical postdepositional processes (Cabanes et al, 2009;Jenkins, 2009). These results indicate that the grasses are not part of the reworked hearth material, and that a certain degree of diachrony must exist between the deposition of the two types of sediment (phytolith-rich beds and reworked hearth material).…”

Irrigation and phytolith formation: an experimental study

“…Before the processing of the modern plants began, an experiment was conducted to compare the impact that analytical methods have on conjoined phytoliths (Jenkins, 2009 processing methods were employed: dry ashing and acid extraction. The former method involves burning the plant samples in a muffle furnace to remove organic matter while the latter uses nitric acid to remove organic matter.…”

“…The first is that the oxidation of the organic matter during acid extraction forces the phytoliths apart and causes a mechanical breakdown of conjoined forms that does not occur with dry ashing or that acid extraction destroys the silica gel holding the phytoliths together (Hayward and Parry, 1980). The second is that dry ashing causes the silica to dehydrate, as proposed by , causing fusion between forms resulting in a stronger structure (Jenkins, 2009).…”

“…This is because these forms are single celled and not subject to break up, a problem with the conjoined phytolith method proposed by Rosen and Weiner (1994). Analytical experiments conducted by Jenkins (2009) demonstrated that conjoined phytolith forms do not remain stable from the time of formation to the time of analysis, and using this method to indicate water availability in assemblages with unknown taphonomic pathways is problematic.…”

Phytoliths: Preparation and Archaeological Extraction

“…An advantage of combustion is that it has been found to better retain some aspects of phytolith form compared with at least some forms of chemical digestion [6]. Combustion also produces higher frequencies of the aggregated phytoliths associated with agricultural irrigation; hence it is a better method for study of these contexts, although the precise mechanism that produces these higher frequencies is not clear [6,7]. Dry ashing (combustion) is the simpler and more widely used procedure, particularly as it is much safer for students and researchers with little background in chemistry and requires less specialized laboratory equipment.…”