The results of 118 REE analyses of Li\|F granites from South China and other countries indicate that there are three variation types of REE pattern curves with different evolution trends from early to late stages of L...The results of 118 REE analyses of Li\|F granites from South China and other countries indicate that there are three variation types of REE pattern curves with different evolution trends from early to late stages of Li\|F granite complex or from lower to upper petrofacies of the Li\|F granite body: (1) the decreasing, (2) the increasing, and (3) the saltatory variation types. The first variation type is called the positive evolution type, attributed to crystallization differentiation. The second is called the reversion evolution type, which represents liquid segregation dominated by vapor\|liquid distillation. The third is called the saltatory variation type, which is formed from liquid segregation dominated by immiscibility. Therefore, the indicatrices of liquid segregation dominated by immiscibility are the saltatory variation type of REE pattern evolution and the separation of the main evolution trend lines either from the sub\|evolution trend lines or from the composition points of Li\|F granites in the diagrams of REE\|(La/Yb)\-N and La/Sm\|La. The indicatrices of liquid segregation dominated by vapor\|liquid fractional distillation are the reverstion evolution type of REE pattern curves and the main evolution trend lines of Li\|F granites directing to the upper right\|hand on the REE\|(La/Yb)\-N and La/Sm\|La diagrams.展开更多
Three carbonate ocelli-bearing lamprophyre dykes have been found in the Laowangzhai and Beiya gold orefields in the northern sector of the Ailaoshan gold deposit zone, Yunnan Province. Ocelli in the lamprophyre dykes ...Three carbonate ocelli-bearing lamprophyre dykes have been found in the Laowangzhai and Beiya gold orefields in the northern sector of the Ailaoshan gold deposit zone, Yunnan Province. Ocelli in the lamprophyre dykes are carbonates composed mainly of dolomite and calcite. Their trace elements, REE and C isotopic compositions are characteristic of carbonatite and the main mineral assemblages, major elements, trace elements and REE in the matrix are similar to those in the carbonate ocelli-barren lamprophyre dykes in the orefields, which are calc-alkaline lamprophyres that derived from the fertile mantle. The results indicate that the carbonate ocelli-bearing lamprophyre dykes in this area were produced at the time when the Himalayan lamprophyre magma evolved to a relatively late stage of silicate-carbonate liquid immiscibility. In the process of magmatic evolution there took place magmatic degassing with CO2 and H2O as the dominant released gases.展开更多
文摘The results of 118 REE analyses of Li\|F granites from South China and other countries indicate that there are three variation types of REE pattern curves with different evolution trends from early to late stages of Li\|F granite complex or from lower to upper petrofacies of the Li\|F granite body: (1) the decreasing, (2) the increasing, and (3) the saltatory variation types. The first variation type is called the positive evolution type, attributed to crystallization differentiation. The second is called the reversion evolution type, which represents liquid segregation dominated by vapor\|liquid distillation. The third is called the saltatory variation type, which is formed from liquid segregation dominated by immiscibility. Therefore, the indicatrices of liquid segregation dominated by immiscibility are the saltatory variation type of REE pattern evolution and the separation of the main evolution trend lines either from the sub\|evolution trend lines or from the composition points of Li\|F granites in the diagrams of REE\|(La/Yb)\-N and La/Sm\|La. The indicatrices of liquid segregation dominated by vapor\|liquid fractional distillation are the reverstion evolution type of REE pattern curves and the main evolution trend lines of Li\|F granites directing to the upper right\|hand on the REE\|(La/Yb)\-N and La/Sm\|La diagrams.
基金This work was supported by the State Basic Research and Development Program (Grant No.1999043203) the State Climbing Program (Grant No. 95-yu-39) and the Innovational Program of the Chinese Academy of Sciences (Grant No. KZCX 2-101). Geological fiel
文摘Three carbonate ocelli-bearing lamprophyre dykes have been found in the Laowangzhai and Beiya gold orefields in the northern sector of the Ailaoshan gold deposit zone, Yunnan Province. Ocelli in the lamprophyre dykes are carbonates composed mainly of dolomite and calcite. Their trace elements, REE and C isotopic compositions are characteristic of carbonatite and the main mineral assemblages, major elements, trace elements and REE in the matrix are similar to those in the carbonate ocelli-barren lamprophyre dykes in the orefields, which are calc-alkaline lamprophyres that derived from the fertile mantle. The results indicate that the carbonate ocelli-bearing lamprophyre dykes in this area were produced at the time when the Himalayan lamprophyre magma evolved to a relatively late stage of silicate-carbonate liquid immiscibility. In the process of magmatic evolution there took place magmatic degassing with CO2 and H2O as the dominant released gases.
