【摘要】 本文根据新几内亚安山岩的化学分析数据与典型埃达克岩进行对比,讨论了巴布亚新几内亚埃达克岩的地球化学特征及其大地构造环境意义。对比结果表明:巴布亚新几内亚埃达克岩微量元素特征为高锶(一般>于400×10-6),Sr/Y比值平均>41.7,重稀土元素Y和Yb含量很低(分别为≤20×10-6和1.9×10-6)。在微量元素蛛网图上有Sr,Ba正异常峰和明显的Nb,Th负异常。稀土元素表现为LREE富集模式,(La/Yb)N比值平均为2.19~18.69。巴布亚新几内亚埃达克岩的M g#值>0.45,87Sr/86Sr值一般<0.7045与典型埃达克岩一相致。巴布亚新几内亚埃达克岩分别位于弧-陆碰撞带大地构造环境中的大洋岛弧和大陆边缘造山带中。埃达克岩的分布区域与世界级斑岩铜-金矿和浅成热泉金矿的成矿带的分布相一致。更多还原

【Abstract】 The geochemical characteristics of adakites in Papua New Guinea is reviewed and discussed on the basis of the results of chemical analysis for the so-called Andesites,and compared to the typical adakites.The comparative results show that the trace elements of adakites for Papua New Guinea are characterized by high Sr content(>400×10-6) and average high Sr/Y ratio >41.7.However,both Y and Yb of heavy REE contents are very low(Y≤20×10-6 and Yb≤1.9×10-6 respectively).There are strongly positive Sr and Ba anomaly peaks and relatively both negative Nb and Th anomaly on the spidergrams of trace element.The REE patterns exhibit LREE enrichment model with average(La/ Yb)N ratios from 2.19 to 18.69.Meanwhile,The adakites of the Papua New Guinea have lower Mg# values>0.45 and87 Sr/ 86Sr< 0.7045 like most typical adakites.The adakites of Papua New Guinea are respectively located at the oceanic island arcs and continental margin orogen zone within the tectonically setting of arc-continent collision zone and their distribution districts are corresponded to the world-scale porphyry copper-gold as well as hot-spring gold zones.更多还原