## 4 Petrography and Geochemistry
### Geochemical Characteristics  
ICP-MS, ICP-AES, and INAA analyses were performed to quantify the major, minor, and rare-earth elements (REEs) to gain an understanding of the lithologic characteristics of the rocks under study. Tables 3 and 4 summarize the results of these analyses. SiO\({}_{2}\) is the most abundant content in all of the rocks, followed by Al\({}_{2}\)O\({}_{3}\) and Fe\({}_{2}\)O\({}_{3}\) as major components. MgO and CaO were found to be the main minor components, and are more abundant in the amphibolite and diabase compared to other rocks. Across all rock types analyzed, SiO\({}_{2}\) content was lowest in the diabases (averaging 35.09 wt.%) and Fe\({}_{2}\)O\({}_{3}\) was highest in the diabases (averaging 27.52 wt.%). These amounts correspond to the high magnetic susceptibility and the magnetite. It was also confirmed that geochemical proportions in the other rock types correspond to their expected or known characteristics, especially in quartzite (Table 4). On the other hand, in the case of gneiss and schist, the schist excavated from Bangi-dong (BSC) shows a similar chemical composition to other gneiss, but the schist from \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Rock Type** & \multicolumn{6}{c}{**Gneiss**} & \multicolumn{6}{c}{**Schist**} \\ \hline
**Sample** & **SGN** & **BGN** & **PGN-1** & **PGN-2** & **PGN-3** & **PGN-4** & **BSC** & **GSC** & **PSC** \\ \hline SiO\({}_{2}\) & 64.92 & 72.16 & 55.96 & 64.02 & 68.29 & 71.60 & 60.07 & 42.76 & 45.69 \\ Al\({}_{2}\)O\({}_{3}\) & 15.60 & 13.30 & 19.18 & 14.13 & 15.51 & 12.97 & 15.77 & 17.94 & 13.61 \\ Fe\({}_{2}\)O\({}_{3}\) & 8.90 & 4.25 & 8.31 & 7.03 & 4.31 & 4.25 & 8.12 & 14.02 & 17.33 \\ MnO & 0.12 & 0.04 & 0.07 & 0.05 & 0.05 & 0.04 & 0.07 & 0.15 & 0.22 \\ MgO & 2.75 & 0.58 & 3.44 & 1.81 & 1.47 & 0.50 & 4.69 & 5.74 & 6.97 \\ CaO & 1.23 & 1.54 & 1.49 & 2.10 & 2.10 & 1.72 & 1.69 & 10.90 & 10.37 \\ Na\({}_{2}\)O & 1.41 & 2.51 & 2.18 & 2.04 & 2.73 & 2.28 & 2.05 & 2.29 & 1.88 \\ K\({}_{2}\)O & 3.36 & 4.43 & 4.15 & 4.12 & 2.96 & 4.68 & 3.78 & 0.25 & 0.61 \\ TiO\({}_{2}\) & 0.66 & 0.59 & 0.77 & 1.06 & 0.44 & 0.69 & 0.97 & 4.65 & 2.01 \\ P\({}_{2}\)O\({}_{5}\) & 0.05 & 0.25 & 0.09 & 0.31 & 0.15 & 0.21 & 0.18 & 0.02 & 0.21 \\ LOI & 1.69 & 0.59 & 3.60 & 2.22 & 1.85 & 0.74 & 3.03 & 1.15 & 1.57 \\ \hline Total & 100.70 & 100.20 & 99.23 & 98.88 & 100.70 & 99.69 & 100.40 & 99.86 & 100.50 \\ \hline Ba & 1450 & 905 & 2000 & 1740 & 647 & 2060 & 1130 & 134 & 207 \\ Cr & 111 & 16 & 214 & 43 & 88 & 1 & 357 & 1 & 161 \\ Hf & 4.8 & 8.5 & 4.8 & 10.1 & 4.5 & 13.8 & 4.0 & 1.3 & 3.9 \\ Rb & 160 & 280 & 170 & 160 & 220 & 150 & 210 & 20 & 20 \\ Sc & 23.1 & 7.0 & 12.0 & 12.5 & 8.2 & 7.0 & 15.5 & 26.3 & 41.8 \\ Sr & 212 & 157 & 310 & 248 & 223 & 276 & 373 & 1541 & 135 \\ Zr & 166 & 328 & 157 & 329 & 146 & 485 & 192 & 37 & 130 \\ Th & 19.8 & 28.5 & 53.0 & 5.0 & 17.4 & 23.0 & 17.1 & 0.5 & 0.5 \\ Ta & 1 & 1 & 1 & 2 & 1 & 1 & 1 & 1 & 1 \\ Y & 61 & 13 & 23 & 15 & 12 & 21 & 21 & 4 & 28 \\ \hline La & 65.4 & 75.8 & 109.0 & 62.0 & 37.7 & 84.3 & 48.8 & 7.1 & 12.9 \\ Ce & 120 & 152 & 205 & 118 & 71 & 173 & 96 & 13 & 29 \\ Ndd & 52 & 66 & 93 & 59 & 37 & 58 & 45 & 7 & 25 \\ Sm & 7.1 & 9.9 & 14.5 & 10.6 & 5.8 & 9.3 & 7.3 & 1.8 & 5.1 \\ Eu & 0.8 & 0.7 & 2.8 & 1.4 & 1.3 & 2.8 & 2.1 & 1.0 & 1.4 \\ Tb & 1.2 & 0.5 & 0.5 & 0.5 & 0.5 & 0.5 & 0.8 & 0.5 & 0.5 \\ Yb & 6.9 & 0.5 & 2.9 & 0.7 & 0.8 & 1.5 & 1.5 & 0.5 & 3.0 \\ Lu & 1.1 & 0.1 & 0.1 & 0.1 & 0.1 & 0.1 & 0.1 & 0.1 & 0.2 \\ \hline (La/Yb)\({}_{\rm N}\) & 6.4 & 102.4 & 25.4 & 59.9 & 31.8 & 38.0 & 22.0 & 9.6 & 2.9 \\ \hline \end{tabular}
\end{table} 
Table 3: Geochemical compositions of major oxides(wt.%) and selected minor and rare-earth elements(ppm) for gneiss and schist. Sample names are as used in Table 1. LOI; loss on ignition. Gamil-dong (GSC) and provenance site (PSC) have a relatively higher CaO content and lower K2O content than other gneiss (Table 3). It is considered to be the result of the difference in mineral composition as confirmed Figures 5 and 6.