Controls on the porphyry Cu-Au mineralizing potential of magmas in continental collision settings

本项目的目的是评价大陆碰撞背景下岩浆因素对斑岩型铜金成矿潜力的影响。一个流行的观点是，高肥力的碰撞后，富钾岩浆源于部分熔融的硫化物丰富的堆积物，沉积在下地壳在前一阶段的俯冲有关的岩浆活动。这一假设将使用一种双重方法进行检验，这种方法涉及对自然样品的实验和研究。在实验中，天然的，硫化物轴承累积将受到高压和高温，以诱导部分熔融，并获得运行产品将彻底的特点，就其组成，氧逸度，和硫，水和金属的丰度在硅酸盐熔体。对自然样品的研究旨在：（1）确定可用作实验起始材料的其他下地壳堆积物的特征，（2）重建与矿化和贫瘠系统有关的一些自然碰撞后岩浆的成分、形成条件和金属含量，以便可以将结果与实验结果直接进行比较。

The aim of this project is to evaluate the influence of magmatic factors on the porphyry Cu-Au mineralizing potential of magmas in continental collision settings. A popular view is that the high fertility of postcollisional, potassium-rich magmas stems from the partial melting of sulfide-rich cumulates that were deposited in the lower crust during a previous stage of subduction-related magmatism. This hypothesis will be tested using a dual approach that involves both experiments and studies on natural samples. In the experiments, natural, sulfide-bearing cumulates will be subjected to high pressures and temperatures to induce partial melting, and the obtained run products will be thoroughly characterized with regard to their composition, the oxygen fugacity, and the abundances of sulfur, H2O and metals in the silicate melt. The studies on natural samples aim at: (1) characterizing additional lower crustal cumulates that can be used as starting materials for the experiments, and (2) reconstructing the composition, formation conditions and metal content of a number of natural, postcollisional magmas associated with both mineralized and barren systems, such that the results can be directly compared with those obtained from the experiments.