# Autochthonous or Allochthonous, the Prehistoric Pottery of Cueva de Los Postes
## 4 Discussion
\begin{table}
\begin{tabular}{l c c c c c c} \hline \hline  & \multicolumn{3}{c}{**Aluminum Silicates**} & & & \\ \hline \multirow{3}{*}{**Al-Oh**} & \multicolumn{3}{c}{**T[A]Si-**} & \multicolumn{3}{c}{**T[A]SI-**} & \multicolumn{3}{c}{**T[A]SI-**} \\  & **O T=A1 o** & **O T=A1** & **Stretching** & & & \\ \hline POST-1E & & 989 vs & & & 3370 sh & \\ \hline POST-1I & & 982 vs & & 2853 w & 2924 w & 3360 sh & \\ \hline POST-2E & & 978 vs & & & 3400 sh & \\ \hline POST-2I & & 988 vs & & & 3396 w & 3530 sh & \\ \hline POST-3E & 916 m & 999 vs & & & 3384 vw & 3618 w & 3694 sh \\ \hline POST-3I & & 994 vs & & & 3400 sh & 3619 vw & 3695 vw \\ \hline POST-4E & 914 m & 999 vs & & 2929 vw & 3364 sh & 3619 w & 3694 vw \\ \hline POST-4I & & 984 vs & & & 3368 sh & \\ \hline POST-5E & & 988 vs & & & 3386 sh & 3600 w & \\ \hline POST-5I & & 987 vs & & & 3399 sh & \\ \hline POST-6E & & 984 vs & 2851 vw & 2925 vw & 3385 sh & 3616 w & \\ \hline POST-6I & & 983 vs & & & 3384 sh & 3616 w & \\ \hline POST-7E & 908 s & 984 vs & & & 3618 w & 3694 vw \\ \hline POST-7I & 911 m & 998 vs & & & 3619 w & 3694 vw \\ \hline POST-8E & & 984 vs & & & 3386 sh & 3620 vw & \\ \hline POST-8I & & 983 vs & & & 3389 sh & 3613 w & \\ \hline POST-9E & & 986 vs & & & 3384 sh & \\ \hline POST-9I & & 995 vs & 2851 vw & 2923 vw & 3386 sh & 3616 w & \\ \hline POST-10E & & 981 vs & & & 3395 sh & \\ \hline POST-11E & & 990 vs & & & 3383 sh & \\ \hline POST-11I & & 990 vs & & & 3376 sh & 3607 w & \\ \hline POST-12E & & 990 vs & & & 3382 sh & 3613 w & \\ \hline POST-12I & & 991 vs & & & 3387 sh & 3600 w & \\ \hline POS22/01 & 913 w & 996 vs & & & 3371 sh & 3617 w & \\ \hline POS22/02 & 916 m & & 1007 vs & 2118 w & 3367 sh & 3618 w & 3692 vw \\ \hline CAB22/01 & 915 m & & 1005 vs & & 2521 vw & 3617 w & 3694 vw \\ \hline CAB22/02 & & & 1005 vs & & 3292 sh & 3615 w & 3689 vw \\ \hline JAR22/01 & 912 m & 996 vs & & & 3362 sh & 3617 w & \\ \hline JAR22/02 & 910 m & & 1002 vs & 1030 vs & & 3622 w & 3694 w \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Table in which only the relative peaks of water and the main aluminum silicates peaks found in the clays are shown. Peaks of different intensities are identified in the spectra, reported in the Table as very strong (vs), strong (s), medium (m), weak (w), very weak (vw), and shoulder (sh). (Edited by [PERSON] and [PERSON]). the pottery vessel and fire it, then add another layer to the surface and fire it again [39; 40]. Macroscopic observation does not show a surface treatment. The only sample in which it is possible to identify this element in both surfaces is POST-6, and only one of the samples analyzed, POST-9, has a decorative grip element to its design (Figure 2). The comparison between the different spectra in Figures 4 and 5 allows us to observe that the composition of the analyzed pottery is substantially homogeneous, with differences in the presence of water, a factor that could be connected to the preparation and firing of the pottery body. Another element that can be seen from the spectra reading is that, in some samples, there is a concentration of organic substances. This concentration is only found in a few samples and is not only found on the inner surfaces but also on the outer surfaces of the pottery fragments. This factor is considered to be due to post depositional actions inside the cave. The presence of organic residues found in the ATR-FTIR spectra is believed to be the result of the use of this pottery and its past origins or alternatively the result of post depositional action and soil contamination (which is considered to be the more plausible explanation in this context). This explanation is supported by the low concentration of organic substances found on the internal surfaces (samples POST-1 peak 2924 and 2853 cm\({}^{-1}\) and POST-9 peak 2923 and 2852 cm\({}^{-1}\)) and external surfaces (samples POST-4 peak 2929 cm\({}^{-1}\), POST-6 peak 2925 and 2851 cm\({}^{-1}\) and POST-10 peak 2978 cm\({}^{-1}\)).