## 5 Discussion
### Petrological Classification and Petrogenesis
However, all these features contradict those shown in the Dazeshan granitoids studied here. Thus, it is impossible that the NCC Archean lower crust is the exclusive or direct source for these granitoids. Furthermore, the melting of the mafic to felsic granulite rocks need high melting temperatures [85,99]. In addition, the middle Early Cretaceous granitoids (132-122 Ma), which have higher SiO\({}_{2}\) (>70.89 wt.%) and lower MgO (<0.62 wt.%) concentrations, and higher (\({}^{87}\)Sr/\({}^{86}\)Sr) values (0.71071-0.71172), were suggested to be derived from the mingling of the felsic melts, produced by the partial melting of Precambrian basement rocks of the Jiaobei terrane, with the intermediate magmas generated by the partial melting of juvenile mafic lower crust [100]. Therefore, it was proposed that Dazeshan granitoids are products of partial melting of the continental lower crust containing subduction-related materials induced by the injection of mantle-derived basic magmas. However, given the very low MgO concentrations and relatively high (\({}^{87}\)Sr/\({}^{86}\)Sr)\({}_{h}\) combined with the lack of any significant fractionation, it is suggested that likely only a few melts or mainly fluids came from the mantle, which is in accordance with the small portion of dark enclaves presented in the Dazeshan granitoids. In the Jiaodong Peninsula, two types of coeval lampprobyres, i.e., low-Ti and high-Ti lampprobyres, were identified to be emplaced at c. 121 Ma. The low-Ti lampprobyres have high SiO\({}_{2}\) concentrations of 49.5-53.9 wt.% and high Mg# (63-74), and show enrichment in both LILEs and LREEs but high depletion in HFSEs, with strongly negative anomalies  
Figure 11: Ratios of REE elements (**a**) and trace elements (**b**) in dark enclaves to their corresponding host granitoids. Ranges for ratios of REE elements (**a**) and trace elements (**b**) in silicic liquid to those in mafic liquid are based on data from [80,89,93,94]. in Zr, Hf, Nb, Ti and Ta (Figures 6e and 7e). They possess highly negative \(\varepsilon\)Nd(t) values (-13.9 to -15.5) and \(\varepsilon\)Hf(t) values (-23.1 to -19.3) and are considered to originate from an enriched subcontinental lithospheric mantle that was metasomatized by subduction-related fluids [47]. The high-Ti lampprohyres have low SiO\({}_{2}\) concentrations of 46.9-49.2 wt.% and Mg# (51-58) and show enrichment in LREEs, but lack Nb-Ta depletion and LILE enrichment (Figures 6f and 7f). They possess higher \(\varepsilon\)Nd(t) values (-0.79 to 1.76) and \(\varepsilon\)Hf(t) values (-4.7 to 2.1) and are considered to originate from an asthenospheric mantle unaffected by subduction-related materials [47]. The elemental and isotopic compositions of the dark enclaves in the Dazeshan granitoids are much closer to those of enriched subcontinental lithospheric mantle beneath the Jiaodong Peninsula as indicated by low-Ti lampprohyres (Figures 6e, 7e and 8), distinct from those of asthenospheric mantle-derived high-Ti lampprohyres in the Jiaodong Peninsula (Figures 6f, 7f and 8). Therefore, it is most likely the enriched subcontinental lithospheric mantle is the source for the mantle-derived materials. Given the very small variations in major- and trace-element contents, such as SiO\({}_{2}\) (68.25-71.56 wt.%), Al\({}_{2}\)O\({}_{3}\) (13.91-15.70%), CaO (2.17-2.79%), Y (7.2-10.9 ppm) and Yb (0.66-1.00 ppm), and the narrow ranges of (La/Yb)\({}_{\rm N}\) ratios (32-50) for the Dazeshan granitoids, it is suggested that the crust-derived materials were likely from almost the same depth.