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Mineralogical Characterization
 Provenance studies of soils at archaeological sites often rely
heavily upon chemical techniques such as ICP-AES. However, soils
with very similar chemical composition can have different
mineralogies (distinctive crystaline structures as well as
variations within the same mineral) that are not revealed by
multi-elemental techniques. Because mineralogical techniques are
often cheap and usually nondestructive, beginning with
mineralogy allows the researcher to gain valuable information
and then to be selective about how many samples are submitted
for expensive and somewhat destructive chemical analysis, thus
conserving both valuable samples and funds.
 Characterization techniques commonly employed in pedology,
namely the use of scanning electron microscopy (SEM) coupled
with energy dispersive X-ray (EDX) analysis, X-ray diffraction (XRD),
and photomicrograph were used to characterize the soils, slag,
and plaster at the site. XRD analysis of bulk plaster samples
showed that there are two main classes of plaster: calcite-rich
(dominant) and gypsum-rich. Calcite-rich plaster consisted
mainly of calcite and trace amounts of quartz. Photomicrograph
and SEM-EDX analysis of the calcite-rich plaster revealed that
calcite is a major mineral and Ca is a major element with Al and
Si (Figure 12). SEM and EDX analysis of gypsum-rich plaster
showed that Ca and S are major elements (Figure 13  ). XRD
analysis showed that slag mineralogy consists mainly of
K-feldspar (Leucite: KAlSi2O6), augite [Ca(Mg,Fe)Si2O6], calcite
CaCO3), and maghemite (Fe2O3) with trace amounts of quartz. SEM
and EDX analysis of slag showed that the chemical composition of
slag is Si, Ca, K, Al, P, Ca, and Fe (Figure 14). |
