## 4 Result
### Geochemical Characteristics of Mineralization and Alteration Zone  
The mean compositions of major and trace elements of the analyzed samples are listed in Table 1. For six unaltered limestones from the Beiya Fm., they have a high content of CaO (34.64 wt.%) and MgO (17.67 wt.%), and a low content of Fe\({}_{2}\)O\({}_{3}\)\({}^{*}\) (0.43 wt.%), Al\({}_{2}\)O\({}_{3}\) (0.60 wt.%), SiO\({}_{2}\) (0.72 wt.%), MnO, K\({}_{2}\)O, Na\({}_{2}\)O, and TiO\({}_{2}\) (Table 1). The contents of metallogenic and rare earth elements in unaltered limestones are relatively low, with Cu,  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sections**} & \multirow{2}{*}{**Sample**} & \multirow{2}{*}{**Mo**} & \multirow{2}{*}{**Cu**} & \multirow{2}{*}{**Au**} & \multirow{2}{*}{**Fe**} & \multirow{2}{*}{**Pb**} & \multirow{2}{*}{**Zn**} & \multirow{2}{*}{**Ag**} & \multicolumn{3}{c}{**Ratios of Element Association**} \\ \cline{4-14}  & & & & & & & & & **Cu + Au  
Pb, and Zn contents of 3.60, 10.40, and 17.00 \(\times\) 10\({}^{-6}\), respectively, while the content of Au and Ag is between 0.01 and 0.02 \(\times\) 10\({}^{-6}\) (Table 1).  
While for fourteen altered or mineralized limestones in the wall-rock alteration zone, the abundances of CaO and MgO are 19.50 and 5.02 wt.%, respectively, there is also a high content of Fe2O3\({}^{*}\) (16.21 wt.%), SiO2 (6.79 wt.%), Al2O3 (2.29 wt.%), and MnO (1.28 wt.%) (Table 1). The contents of major metallogenic and rare earth elements from altered or mineralized limestones are high, with Cu, Pb, and Zn contents of 1540.00, 17,190.00, and 7234.00 \(\times\) 10\({}^{-6}\), respectively, and Au (3.45 \(\times\) 10\({}^{-6}\)) and Ag (15.70 \(\times\) 10\({}^{-6}\)) also showing a high content (Table 1). Significantly, the content of P2O5 between unaltered limestones (0.050 wt.%, n = 6) and altered or mineralized limestones (0.053 wt.%, n = 14) is almost consistent (Table 1).  
Unaltered quartz syenite porphyry has a high content of Al2O3 and SiO2 (16.98 and 67.78 wt.%, respectively, n = 3), and a low content of Fe2O3\({}^{*}\) (2.70 wt.%, n = 3), CaO, MgO, MnO, Na2O, and TiO2, with the content of K2O and P2O5 being about 7.11 and 0.060 wt.%, respectively (Table 1). The Cu, Pb, Zn, Au, and Ag contents of unaltered quartz syenite porphyry are about 14.27, 103.40, 82.90, 0.01, and 0.66 \(\times\) 10\({}^{-6}\), respectively, showing the characteristics of low content.  
With regard to the altered quartz syenite porphyry from four different porphyry alteration zones, they have various content and compositions of major and trace elements (Table 1). For instance, the altered quartz syenite porphyries in the potassic zone contain the highest amounts of Fe2O3\({}^{*}\) (10.53 wt.%), K2O (7.68 wt.%), Cu (20,770.00 \(\times\) 10\({}^{-6}\)), Au (5.88 \(\times\) 10\({}^{-6}\)), and Ag (84.84 \(\times\) 10\({}^{-6}\)) (Table 1), while they have the highest amounts of SiO2 (69.80 wt.%) and the lowest amounts of K2O (4.63 wt.%) in the phyllic zone (Table 1). The content of P2O5 of altered quartz syenite porphyries, in addition to that in the propylitic zone (P2O5 = 0.033 wt.%), is about 0.061, 0.064, and 0.067 wt.% in the potassic, phyllic, and argillic zones (Table 1), respectively, which is consistent with that of unaltered quartz syenite porphyry.  
In the contact alteration zone, exoskarn and endoskarn show different element compositions due to the difference of protoliths. Altered rocks in the exoskarn zone have a relatively high content of CaO (14.10 wt.%) and MgO (9.92 wt.%), while they have a high content of SiO2 (45.80 wt.%) in the endoskarn zone, which is preferred to the compositional features of the respective protoliths. Both exoskarn and endoskarn have a high content of Fe2O3\({}^{*}\) (Table 1). The P2O5 content varies greatly in the exoskarn zone (0.040 wt.%) and endoskarn zone (0.073 wt.%) (Table 1).