| An evaluation of current techniques used in the forensic analysis of soils and geologic evidence. Research was performed to determine the discriminative qualities of the various procedures to see at what point soils could not be distinguished from one another. Included in this research is an assessment of the techniques from a worker standpoint to determine what level of advanced instrumental analysis is required to segregate samples from one another.;One hundred samples were collected from three different sites; a beach, an island isolated by a river, and a bus parking lot. The samples were analyzed using color determination using the Munsell Color Charts, particle size distribution analysis utilizing Mean, Median and Dispersion measurements as described by Pettijohn, and mineralogical profiles of the twenty-five most common soil minerals. Of the three hundred samples examined, over one-half could be discriminated by color alone, the remainder needing only particle size distributions analysis to differentiate them, negating the need for lengthy mineralogical profile examinations.;The unique feature of this analysis is the use of eight sieves in the particle analysis. This allowed a broader statistical base in which the distributions could be better assessed by environmental interactions. These examinations were performed with very inexpensive equipment that could be operated and calculations performed with a minimum of training and cost.;The overall conclusions drawn from this experiment is that soils can be individualized down to distances of 10 meters apart and that examinations can be economical and easily performed. This contradicts the old ideas that soil analysis is of little forensic value and that extensive geologic training and equipment is required to perform them. |
