# Chemical Signatures of Ge in Magnetic of Wugang BIF, China
## 3 Results and Discussion  
### Geochemical Properties of Ge in Magnetite in Various Ore Deposits  
Ge is used as a direct or indirect geochemical factor to evaluate the genetic condition of ore deposits because its concentration and chemical behavior are controlled by hydrothermal fluids, partition coefficients, and physicochemical conditions, such as temperature, and oxygen and sulfur fugacity [14; 39]. [PERSON], [PERSON], [PERSON] and [PERSON] [22] summarized the concentration and chemical behavior of Ge in magnetite from the Fe-Ti-(V) oxide deposit in the Emeishan large igneous province of SW China containing Taibe, Baima, Hongge, Panzhihua, and Anyi intrusions with Fe-Ti-P deposits [39]; Bushveld complex of South Africa, Sept-Iles intrusive Suite of Canada, and St. Charles de Bourget of Canada; Ni-Cu-platinum-group elements (PGE) deposits of the Sudbury igneous complex in Canada [40]; Voisey's Bay anorthosite complex in Canada [41]; Noril'sk-Talanakh intrusion in Siberia [42]; Huang-shandong intrusion in China [43; 44]; Sokoman iron formation in the Labrador Trough of Canada [11]; Skarn Fe deposits of the Nanjing Range, South China [38]; in Tongling, Eastern China [45]; and Vegas Peledas of Argentina [39]; IOCG deposits in the Kangdian metallogenic province of SW China [46; 47]; igneous derived hydrothermal Fe deposits of the Cihai Fe deposit in the Beishan terrane of NW China [48]; and Heifengshan, Shuangfengshan, and Shaquanzi Fe deposits in the Eastern Tianshan Orogenic Belt of NW China [49]. These studies provided information on the chemical behavior of Ge in each ore deposit. In the case of Fe-Ti-P deposits, the concentration of Ge in magnetite varies from 0.69 to 26.6 ppm, and its wide range is indicative of different degrees of magmatic evolution [39; 50]. High Ge content magnetite is enriched in Zn and Ga and depleted in Cr, Co, and Ni [39]. In Ni-Cu-PGE deposits, magnetite occurs as an accessory mineral with a concentration of 0.15-1.27 ppm of Ge with an average of 0.74 ppm [33]. The geochemical affinity of Ge is similar to those of Cr, Ti, V, Al, Mn, and Ga and is compatible with iron oxide in sulfide melts [33]. The concentration of these lithophilic elements in iron oxide gradually decreases during the continuous crystallization of iron oxide from the sulfide liquid [33]. [PERSON] et al. [11] investigated three types of magnetite (primary, altered, and volcanic breccia) in the Sokoman Iron Formation in the Labrador Trough of Canada, to compare trace element composition trends. The three types of magnetite exhibited different trends in trace element composition. The primary, altered, and volcanic breccia magnetites contain Ge concentrations of 13-39 ppm (average 23 ppm), 3.8-110 ppm (average 25 ppm), and 12.1-247 ppm (average 59 ppm), respectively [11]. The trace element composition of primary magnetite is homogeneous, whereas that of altered magnetite varies widely, indicating the role of exhalative volcanic processes and hydrothermal fluids in modifying the trace element composition of magnetite [11; 22]. The magnetite in the Fe-Ti-(V) oxide ore deposits exhibited extensive trellis or sandwich exsolution lamellae of ilmenite and spinel, and had variable trace element concentrations owing to their crystallography (such as the affinity of the ionic \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline  & **FeOT** & **MnO** & **Cr2O3** & **MgO** & **SiO2** & **K2O** & **CaO** & **TiO2** & **Na2O** & **Al2O3** & **Total** \\ \hline Min & 89.2 & - & - & - & - & - & - & - & - & - & 89.6 \\ Max & 94.2 & 0.2 & 0.1 & 0.1 & 0.3 & 0.2 & - & 0.1 & 0.4 & 0.1 & 94.5 \\ Median & 92.2 & 0.1 & - & - & - & - & - & - & - & - & - \\ Standard deviation & 1.0 & - & - & - & - & - & - & - & - & - & - \\ \hline \end{tabular}
\end{table} 
Table 1: Major element abundance of magnetite from Wugang BIF (n = 64, wt. %).