Detection of bone particles in non-carbonate soils

Abstract

A routine geologic test for the presence of carbonate minerals in soil is the application of dilute hydrochloric acid (HCl) and observation for an effervescent reaction. This study tests whether non-carbonate soils can exhibit effervescence in the presence of HCl if bone particles are present in the soil. Five bone fragments displaying various taphonomic alterations were ground and sieved to achieve uniform particle size fractions. A non-carbonate soil was mixed with each bone particle fraction, and 1 molar HCl solution was applied while observing the reaction using a stereo microscope. All tests resulted in the effervescence of bone particles, which could be easily located within the soil based on the presence of small bubbles surrounding the bone particle. These results show that a simple, quick, cost-effective test can be used to presumptively determine whether soil may contain bone particles, even if they are too small to be identified morphologically. Results also suggest that, since bone particles in soil can produce the same type of effervescence expected in carbonate soil, additional tests may be needed to determine the source of an effervescent reaction. These findings also highlight the insight that can be gained through interdisciplinary discussions and investigations.