## 3 Results and Discussion
### FTIR Spectroscopy  
FTIR absorption spectra were recorded on both the surface layer and the inside bulk material of the samples in the entire mid-IR region (4000-400 cm\({}^{-1}\)). However, the mineral composition of the slags could be altered during burial, the alteration process depending on the environmental conditions. The altered layer forms starting from the surface and progresses over time deeper and deeper towards the bulk, the possible modifications affecting primarily the 4000-1500 cm\({}^{-1}\) (principally OH and CO\({}_{2}\) governed) region of the FTIR spectra. Considering that, for the time being, in this specific case, an adequate study of these aspects is not available, FTIR spectral data interpretation is limited to the less affected 2000-400 cm\({}^{-1}\) spectral domain (Figure 3). Except for a few cases (9445 and Vat), the absorption peaks of the FTIR spectra recorded on the outer layer and the inside bulk of the samples in the 2000-400 cm\({}^{-1}\) domain practically coincide, suggesting that, even if some geochemical processes took place during burial, their influence is mostly negligible. The \"deviancy\" of some findings probably must be ascribed to specific micro-environmental influences; an adequate explanation would necessitate a deeper investigation of the exact location of the unearthing. The frequency assignment of the main absorption peaks in the 2000-400 cm\({}^{-1}\) spectral domain is presented in Table 7; spectral data were interpreted considering literature data published [30; 31; 32; 33]. As the FTIR spectra recorded on the outer layer and the inside bulk of the samples in the 2000-400 cm\({}^{-1}\) region (in most cases) are practically superposed, it can be considered that the FTIR behavior is satisfactorily described by the inside (bulk) data. With minor differences, Table 7 data indicate a close spectral behavior of the samples, independently from the exact location of their uncovering. According to the absorption peaks appearing in the spectral domain 2000-400 cm\({}^{-1}\), the samples are mainly constituted from silicates, aluminosilicates, and aluminates. Carbonates, formed most probably in environmentally induced carbonation processes occurring during burial, are also present. Other additional differences can also be attributed to burial conditions. The CO\({}_{2}\) peaks on some spectra appeared probably due to the groundwater or humid soil caused deep carbonation. All this denotes the relative closeness of the smithery practiced on the different locations where most probably the iron objects were processed starting from pig-iron (bloom) of relatively close provenance, using a similar technology. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{6}{c}{**Iron Slag Sample**} \\ \cline{2-7}
**Mineral Phases** & **4137** & **4264** & **9487** & **9445** & **9454** & **Vat** \\ \cline{2-7}  & **C1/2034** & **C1/2038** & **A/1** & **A/3** & **A/3** & **V1** \\ \hline Quartz & ++++ & ++++ & ++++ & ++++ & ++++ & + \\ Cristobalite & tr & tr & ++ & ++ & + & tr \\ Goethite & ++++ & tr & ++ & ++ & + & tr \\ Magnetite & tr & + & nd & tr & tr & tr \\ Hedenbergite & tr & tr & tr & nd & nd \\ Glassy phase & ++ & ++ & ++++ & ++ & + & +++ \\ \hline \hline \end{tabular}
\end{table} 
Table 6: The most abundant PXRD—identified mineral phases of the selected slags. Figure 3: FTIR spectra recorded on the external layer (black line) and on the bulk (red pattern) of the selected samples (Bra: Brâncovenesti; Cal: Calugäareni; Vat: Vätava).