This paper systematically reports geochemical data of lamprophyres which are temporally andspatially related to Au mineralization in the Laowangzhai gold deposits, Yunnan Province. Majorelements show that lamprophyres...This paper systematically reports geochemical data of lamprophyres which are temporally andspatially related to Au mineralization in the Laowangzhai gold deposits, Yunnan Province. Majorelements show that lamprophyres in the orefield are alkalic series and potassic calc-alkaline lam-prophyres. Chondrite-normalized transition element patterns of the lamprophyres are "W" shapedwhich suggest that the rocks are mantle-derived. The lamprophyres are enriched in large ionlithophile elements (LlLE ), high field strength elements (HFSE ) and rare earth elements(REE), and have high 87Sr/86Sr but low 143Nd/144Nd ratios. All the characteristics above and cal-culation modelling suggest that the source of the lamprophyres is incompatible element-enrichedmetasomatic mantle.展开更多
Lamprophyres are widely spread over the Laowangzhai gold orefield in northern Mt. Ailao structure zone, Yunnan Province. Lamprophyres in the orefield are temporally and spatially related to gold mineralization. Lampro...Lamprophyres are widely spread over the Laowangzhai gold orefield in northern Mt. Ailao structure zone, Yunnan Province. Lamprophyres in the orefield are temporally and spatially related to gold mineralization. Lamprophyres in the orefield have anomalous Sr and Nd isotopic compositions, e.g. the 87Sr/ 86Sr ratios (0.706 665-0.707 960, the 87Sr/ 86Sr ratio of sample YLW-44 is 0.709 041) are higher than the modern value of the original mantle (0.704 5), the 143Nd/ 144Nd ratios (0.512 463-0.512 551) are lower than the modern value of the original mantle (0.512 638), and the calculated values ε Sr>0 (28.1-63.7) and ε Nd<0 (-1.34--3.07). The results of investigation indicate that lamprophyres in the Laowangzhai gold orefield with anomalous Sr and Nd isotopic compositions would not be produced as a result of contamination of the primary magma with the isotopic features of MORB by the crust materials high 87Sr/ 86Sr ratios and low 143Nd/ 144Nd ratios in the processes of rising or in the magma chamber, but the result of metasomatism of source mantle.展开更多
文摘This paper systematically reports geochemical data of lamprophyres which are temporally andspatially related to Au mineralization in the Laowangzhai gold deposits, Yunnan Province. Majorelements show that lamprophyres in the orefield are alkalic series and potassic calc-alkaline lam-prophyres. Chondrite-normalized transition element patterns of the lamprophyres are "W" shapedwhich suggest that the rocks are mantle-derived. The lamprophyres are enriched in large ionlithophile elements (LlLE ), high field strength elements (HFSE ) and rare earth elements(REE), and have high 87Sr/86Sr but low 143Nd/144Nd ratios. All the characteristics above and cal-culation modelling suggest that the source of the lamprophyres is incompatible element-enrichedmetasomatic mantle.
文摘Lamprophyres are widely spread over the Laowangzhai gold orefield in northern Mt. Ailao structure zone, Yunnan Province. Lamprophyres in the orefield are temporally and spatially related to gold mineralization. Lamprophyres in the orefield have anomalous Sr and Nd isotopic compositions, e.g. the 87Sr/ 86Sr ratios (0.706 665-0.707 960, the 87Sr/ 86Sr ratio of sample YLW-44 is 0.709 041) are higher than the modern value of the original mantle (0.704 5), the 143Nd/ 144Nd ratios (0.512 463-0.512 551) are lower than the modern value of the original mantle (0.512 638), and the calculated values ε Sr>0 (28.1-63.7) and ε Nd<0 (-1.34--3.07). The results of investigation indicate that lamprophyres in the Laowangzhai gold orefield with anomalous Sr and Nd isotopic compositions would not be produced as a result of contamination of the primary magma with the isotopic features of MORB by the crust materials high 87Sr/ 86Sr ratios and low 143Nd/ 144Nd ratios in the processes of rising or in the magma chamber, but the result of metasomatism of source mantle.
