Accessory minerals as fertility indicators in copper porphyry systems

斑岩铜矿占世界铜资源的四分之三。尽管人们对导致矿化的过程普遍达成了更大的共识，但人们仍然在争论是什么使岩浆系统“肥沃”，具有形成大型资源的能力。由于斑岩矿化的含水性质，整个岩石地球化学往往是扭曲的，并可能误导。分析强大的辅助矿物，如锆石，提供了独特的机会，透过蚀变和研究岩石成因期间以前活跃的岩浆条件。我的项目旨在比较“肥沃”和“贫瘠”岩浆（没有矿化潜力）中几种辅助矿物的地球化学。这将包括研究来自菲律宾吕宋岛世界级的圣托马斯II铜金矿床的成矿前、成矿同期和成矿后岩石。这些地球化学特征将与现代类似的“肥沃”（皮纳图博）和“贫瘠”（塔尔）系统中发现的地球化学特征进行比较。这将使我们能够研究导致斑岩铜肥力产生的关键岩浆过程，但这一过程仍然模糊不清。该项目还将调查据信在塔尔形成的岩浆盐水透镜的作用。

Porphyry copper deposits host three quarters of the worlds copper resources. Despite generally greater agreement on the processes leading to mineralization, it is still debated what makes a magmatic system 'fertile', possessing the ability to form large resources. Due to the hydrous nature of porphyry mineralization, whole rock geochemistry is often distorted and potentially misleading. Analysing robust accessory minerals e.g. zircon grants the unique opportunity to see through alteration and investigate the previously active magmatic conditions during petrogenesis. My project aims to compare the geochemistry of several accessory minerals within 'fertile' and 'barren' magmas (no potential for mineralisation). This will involve the study of pre-, syn- and post-mineralization rocks from the world class Santo Thomas II Cu-Au deposit, Luzon, Philippines. These geochemical signatures will be compared with those found in modern analogues of 'fertile' (Pinatubo) and 'barren' (Taal) systems. This will allow the investigation of key magmatic processes leading to the, still ambiguous, generation of porphyry copper fertility.This project will also investigate the role of magmatic brine lenses believed to be forming at Tall.