## 4 Analytical Results
### Whole-Rock Geochemistry  
The major- and trace-element compositions for the monzogranites and their dark enclaves are shown in Figure 5 and Table A1. The rocks analyzed all have small loss on ignition (LOI) between 0.43% and 1.33% (Table A1), suggesting that these samples did not suffer any significant post-magmatic alteration, which is in accordance with the petrographic observations both in the field and from the thin sections (Figure 2). Figure 5: (**a**) Total alkali versus silica (TAS) diagram [61]. (**b**) K\({}_{2}\)O vs. SiO\({}_{2}\) classification diagram [62]. (**c**) A/NK (molar Al\({}_{2}\)O\({}_{3}\)/(Na\({}_{2}\)O + K\({}_{2}\)O)) vs. A/CNK (molar Al\({}_{2}\)O\({}_{3}\)/(CaO + Na\({}_{2}\)O + K\({}_{2}\)O)) diagram [63]. (**d–f**) Harker variation diagrams show the correlations of Al\({}_{2}\)O\({}_{3}\), MgO and CaO with SiO\({}_{2}\). The data for middle Early Cretaceous graninidoids (132–122 Ma) [64; 65; 66] and Late Early Cretaceous graninoids (118–110 Ma) [49; 50] previously published are also shown on the Figures. Granitoids of the Dazeshan pluton are acidic in composition and have SiO\({}_{2}\) contents ranging from 68.25 wt.% to 71.56 wt.% (Table A1; Figure 5a). They show high total alkalis (Na\({}_{2}\)O + K\({}_{2}\)O = 7.29-9.00 wt.%), mainly falling into the domain of the sub-alkaline monozgranite on the diagram of SiO\({}_{2}\) vs. (Na\({}_{2}\)O + K\({}_{2}\)O) (Figure 5a). These samples have relatively high K\({}_{2}\)O concentrations of 3.44-5.50 wt.%, with K\({}_{2}\)O/Na\({}_{2}\)O of 0.89-1.57, and are in the domains of high-K calc-alkaline and shoshonite on the K\({}_{2}\)O vs. SiO\({}_{2}\) diagram (Figure 5b) [62], indicating the overall potassic character (Figure 5b). They have a narrow range in contents of Al\({}_{2}\)O\({}_{3}\) (13.91-15.70 wt.%), CaO (2.17-2.79 wt.%), TiO\({}_{2}\) (0.26-0.36 wt.%), TFe\({}_{2}\)O\({}_{3}\) (1.98-2.69 wt.%) and P\({}_{2}\)O\({}_{5}\) (0.10-0.161 wt.%) (Table A1). Based on the aluminum saturation index A/CNK (molar Al\({}_{2}\)O\({}_{3}\)/(CaO + Na\({}_{2}\)O + K\({}_{2}\)O)), granitoids of the Dazeshan pluton show metaluminous to weakly peraluminous character, with A/CNK of 0.94-1.01 (Figure 5c). All these analyzed granitoids have a very narrow range of low MgO concentrations (0.76-1.11%), with the Mg# molar 100*MgO/(MgO + FeO\({}_{7}\)) of 40-43. Enclaves in the Dazeshan pluton, having the SiO\({}_{2}\) concentrations of 54.25-56.84 wt.%, are intermediate in composition and correspond to syenoidorite (Figure 5a). They have higher contents of TiO\({}_{2}\) (0.70-1.02 wt.%), Al\({}_{2}\)O\({}_{3}\) (16.93-17.96 wt.%), TFe\({}_{2}\)O\({}_{3}\) (6.86-8.65 wt.%), CaO (3.81-4.85 wt.%), P\({}_{2}\)O\({}_{5}\) (0.45-0.67 wt.%) and MgO (3.05-4.39 wt.%), with a higher Mg# of 44-49 as compared those of the host granitoids (Table A1). These enclave samples have relatively high total alkalis concentrations of 7.69-9.97%, with variable K\({}_{2}\)O contents of 2.64-6.15 wt.% and K\({}_{2}\)O/Na\({}_{2}\)O ratios of 0.49-1.61, showing alkaline and shoshonite characteristics (Figure 5b), and they are metalluminous, having A/CNK of 0.84-0.91 (Figure 5c). For granitoids and their enclaves, the major oxides of MgO, Al\({}_{2}\)O\({}_{3}\) and CaO concentrations generally have negative correlations with SiO\({}_{2}\) values (Figure 5d-f). As shown in Table A1 and the chondrite-normalized REE diagrams (Figure 6a), both granitoids of the Dazeshan pluton and their enclaves are characterized by high total REE concentrations, with the \(\Sigma\)REE being 138-220 ppm and 359-572 ppm, respectively. Both are rich in LREE, with the ratios of (La/Yb)\({}_{\rm N}\) varying between 32 and 50 for the granitoids and varying between 15 and 47 for the enclaves. The enclaves show moderate negative Eu anomalies, having Eu/Eu* values of 0.45-0.65 (Figure 6a), whereas the granitoids possess unclearly negative Eu anomalies (Eu/Eu* = 0.73-1.00), except that one sample has Eu/Eu* ratio of 0.66 (Figure 6a).