# Age and Source of the Jinjingzui Skarn-Type Gold Deposit in the Southeastern Hubei Province, China
## 5 Discussion
### Implications of Regional Mineralization
There are divergent perspectives within the academic community regarding the tectonic background of rock formation and mineralization in the middle and lower reaches of the Yangtze River. Some scholars argue that this region's tectonic setting is intraplate, while others propose a subduction-related tectonic setting [4; 5; 45; 46; 47]. Despite these differing views, an increasing body of evidence supports the formation of skarn-type polymetallic deposits in this area under conditions of lithospheric extension and thinning [48; 49]. During the Late Jurassic to Early Cretaceous, the middle and lower reaches of the Yangtze River and the broader eastern China area experienced a significant transition from a north-south Indonesian tectonic regime to a northeast-oriented Paleo-Pacific tectonic regime [50]. Regional mineralization events during this period are likely closely associated with this major tectonic transformation. Geophysical data show that the primary metal deposits in the MLYRVB are located in areas of minimal crustal thickness, further corroborating the strong link between lithospheric extension and large-scale mineralization [9]. Through their analysis of deep seismic reflection profiles in the region, [PERSON] et al. (2004) concluded that the delamination and extension of the lithospheric mantle triggered the underplating of mafic or ultramafic magmas [51]. The relatively uniform \(\varepsilon\)Nd(t) and zircon Hf isotopic compositions suggest that the Jinjingzui diorite likely originated from an enriched lithospheric mantle [28]. The Mg# values (30.18 to 39.17) are significantly lower than those of mantle peridotite equilibrium \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Deposit** & **Mineral** & **Method** & **Age (Ma)** & **Cite** \\ \hline Jinjingzui Au deposit & molybden & Re–Os & \(138.5\pm 2.7\)Ma & This study \\ \hline \multirow{3}{*}{Tongshankou Cu-Mo deposit} & molybden & Re–Os & \(143.8\pm 2.6\) & \multirow{3}{*}{[7]} \\  & phlogopite & \({}^{40}\)Ar–\({}^{39}\)Ar & \(143.8\pm 0.8\) & \\ \cline{2-4}  & phlogopite & \({}^{40}\)Ar-\({}^{39}\)Ar & \(143\pm 0.3\) & [44] \\ \cline{2-4}  & molybden & Re–Os & \(142.9\pm 1.8\) & \multirow{3}{*}{[11]} \\ \hline Tonglushan Cu-Fe-Au deposit & molybden & Re–Os & \(138.1\pm 1.8\) & \\ \cline{2-4}  & molybden & Re–Os & \(137.8\pm 1.7\) & \\ \cline{2-4}  & & Re–Os & \(137.3\pm 2.4\) & [10] \\ \cline{2-4}  & phlogopite & \({}^{40}\)Ar-\({}^{39}\)Ar & \(140.3\pm 1.1\) & [11] \\ \hline Qianjiawan Cu-Au deposit & molybden & Re–Os & \(137.7\pm 1.7\) & [10; 40] \\ \hline Ruanjiran W-Cu deposit & molybden & Re–Os & \(143.6\pm 1.7\) & \multirow{3}{*}{[11]} \\ Fengshandong Cu-Mo deposit & molybden & Re–Os & \(144.0\pm 2.1\) & \\ \cline{2-4}  & molybden & Re–Os & \(150.8\pm 0.82\) & [17] \\ \cline{2-4}  & molybden & Re–Os & \(149.5\pm 1.2\) & [41] \\ \hline Jiguanzui Au-Cu deposit & molybden & Re–Os & \(138.2\pm 2.2\) & [10] \\ \cline{2-4}  & molybden & Re–Os & \(138.2\pm 2.2\) & [10] \\ \hline Tieshan Fe deposit & phlogopite & \({}^{40}\)Ar-\({}^{39}\)Ar & \(140.9\pm 1.2\) & \multirow{3}{*}{[43]} \\ Chengchao Fe & phlogopite & \({}^{40}\)Ar-\({}^{39}\)Ar & \(132.6\pm 1.4\) & \\ \cline{2-4}  & molybden & \({}^{40}\)Ar-\({}^{39}\)Ar & \(131.6\pm 1.2\) & \\ \cline{2-4}  & molybden & Re–Os & \(139.4\pm 2.0\) & \\ \cline{2-4}  & molybden & \({}^{40}\)Ar-\({}^{39}\)Ar & \(139.9\pm 1.1\) & [11] \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Ages of deposits in Edong district. mels (70 to 80) [14; 29], indicating that the diorite could not have been directly formed by low-temperature partial melting of mantle peridotite. Instead, it is more plausible that the diorite formed through partial melting of an enriched mantle source region, producing basaltic magma that subsequently underwent magmatic evolution and differentiation. Additionally, the absence of inherited zircons suggests that crustal contamination was minimal during the petrogenesis of the ore-forming rocks [14].