Zircon U–Pb Ages and Geochemistry of Granite Porphyries in the Yangla Cu Deposit, SW China: Constraints on Petrogenesis and Tectonic Evolution of the Jinshajiang Suture Belt
Table 7
Characteristics of the granite porphyries and granodiorite in Yangla copper deposit, Yunnan, China.
Sample
Color
Minerals
Texture and structure
Diagenetic age
Characteristics of major elements
Characteristics of trace elements
Characteristics of REEs
Tectonic setting
Reference
GP
Grayish-white
Quartz: 20–35% Plagioclase: approximately 10–20% Biotite: 5–10% Secondary minerals: sericite, chlorite, and carbonate minerals
Porphyritic/localized porphyritic texture Massive, veined, and banded structure
213, 198.40, and 195.3 Ma (zircon U-Pb dating)
(avg. 68.11 wt.%), (avg. 0.28 wt.%), (avg. 12.26 wt.%), (avg. 3.92 wt.%), MgO =0.50-1.48% (avg. 0.93 wt.%), (avg. 0.05 wt.%), (avg. 4.77 wt.%), (avg. 0.07 wt.%), (avg. 2.39 wt.%), (avg. 0.03 wt.%), (avg. 0.25), (avg. 1.35), (avg. 40.82), (avg. 2.46 wt.%), (avg. 1.24), (avg. 3.53). Trend of negative correlations between SiO2 and TiO2, Al2O3, Fe2O3T, MgO, and CaO. Trend of positive correlations between SiO2 and MnO, K2O, and P2O5. Low Na2O, Na, Fe, Mg, Mn, and P contents. Overall enrichment in Si, Al, K, and Ca. Based on the aforementioned attributes should be metaluminous-peraluminous S-type granite in a calc-alkaline series.
Low content of transition elements Sc, V, Cr, Co, and Ni. Low contents of LILEs Rb, Sr, and Cs. Relative deficit of HFSEs Nb, Zr, ta, Th, U, Hf, and Y. Relatively high contents of ore-forming elements (). Trend of negative correlations between SiO2 and Sc, V, Cr, Co, Ni, Cu, Ga, Sr, Pb, Zn, and Y. Trend of positive correlations between SiO2 and Rb, Cs, Hf, Ta, Th, and U. Zr and Nb contents is relatively stable.
,,,,, (avg. 0.70), (avg. 0.20). Relatively high total REE contents. Significant fractionation between LREEs and HREEs. Strongly enriched in LREEs. Relatively depleted in HREEs with obvious fractionation. Prominently right-trending distribution curve. Significant weak negative Eu anomalies.
Medium- to coarse-grained texture Massive structure
208-239 Ma (zircon U-Pb and hornblende Rb-Sr dating)
(avg. 67.37 wt.%), (avg. 0.37 wt.%), (avg. 15.34 wt.%), (avg. 3.44 wt.%), (avg. 1.37 wt.%), (avg. 0.05 wt.%), (avg. 2.97 wt.%), Na2O =2.72-4.65 wt.% (avg. 3.32 wt.%), (avg. 3.46 wt.%), (avg. 0.09 wt.%), (avg. 1.91), (avg. 2.22), (avg. 1.08), (avg. 6.77 wt.%), (avg. 1.05), (avg. 1.68). Trend of negative correlations between SiO2 and TiO2, Al2O3, Fe2O3T, MgO, MnO, CaO, and Na2O. Trend of positive correlations of SiO2 and K2O with P2O5. Low Fe, Mg, Mn, and P contents. Overall enrichment in Si, Al, K, Na, and Ca. Based on the aforementioned attributes should be metaluminous-peraluminous I-type granite in a calc-alkaline series and high potassium-alkaline series.
Low content of transition elements Sc, V, and Co. Relatively high contents of Cr and Ni. Relatively high contents of LILEs Rb and Sr (>100 ppm). Low contents of LILE Cs. Relative deficit of HFSEs Nb, Zr, Ta, Th, U, Hf, and Y. Relatively low contents of ore-forming elements (). Trend of negative correlations between SiO2 and Sc, V, Cr, Co, Ni, Ga, Sr, Zr, Zn, and Y. Trend of positive correlations between SiO2 and Rb, Cs, Hf, Ta, Pb, Th, and U. Cu and Nb contents relatively stable.
,,,,, (avg. 0.77), (avg. 0.18). Relatively high total REE contents. Significant fractionation between LREEs and HREEs. Strongly enriched in LREEs. HREE fractionation is not obvious. Smooth and right-trending distribution curve. Insignificant weak negative Eu anomalies.
