Behavior of chalcophile elements in subduction zones

我将研究在弧火山形成的俯冲带中亲铜（类铜）元素的行为。这些元素与浅层地壳岩石中的硫有亲和关系，还包括许多我们社会所必需的金属，比如铜。大多数岩石主要由硅酸盐组成，亲铜元素仅以微量浓度存在。具有经济开采价值的金属矿床产于火山弧中，这些火山弧是在海洋岩石俯冲的地方形成的。这种金属矿床与俯冲带之间的空间联系表明了一种联系；然而，在极深的地方，由于俯冲作用导致岩石融化，从而导致弧火山作用，金属的行为却鲜为人知。在过去的研究中，我的团队已经证明，氧化岩浆含有高浓度的硫和金属，而氧化状态反映了底层地幔的性质。菲律宾皮纳图博火山喷出的大量二氧化硫是火山下面高度氧化的地幔造成的。我们还从喜马拉雅山和南美洲的工作中发现，地幔氧化条件受到俯冲物质的影响。地幔的硫含量很低，这就要求火山释放的大量硫由俯冲板块提供。我的研究将有助于回答几个问题：硫和金属是如何从俯冲板块转移到地幔，然后转移到可能爆发的岩浆中，这些金属是如何在s -贫地幔中出现的？为了我们的研究，我们将研究三种类型的岩石；那些被深深俯冲并带回地表的，在造山过程中被抬升的地幔碎片，以及被火山爆发带到地表的地幔碎片。

I will investigate the behaviour of chalcophile (copper-like) elements in subduction zones where arc volcanoes form. Such elements have an affinity for sulphur in shallow crustal rocks, and include many metals that are necessary for our society, such as copper. Most rocks consist largely of silicates, and the chalcophile elements are present in only trace concentrations. Metal deposits that are economic to mine occur in volcanic arcs that are formed where oceanic rocks are subducted. This spatial association between metal deposits and subduction zones indicates a linkage; however, metal behaviour at great depths, where subduction causes melting of rocks that leads to arc volcanism, is little known. In past research, my team has shown that oxidized magmas contain high concentrations of sulphur and metals, and that the oxidation state reflects the nature of the underlying mantle. The discharge of huge amounts of SO2 from Mt. Pinatubo, Philippines, was a consequence of the highly oxidized mantle below the volcano. We have also shown from work in the Himalayas and S. America that the mantle oxidation condition is affected by the subducted material. The mantle has low sulfur, requiring the large discharge of sulfur from volcanoes to be supplied from the subducted plates. My research will help to answer several questions: How are sulfur and metals transferred from the subducting plate to the mantle, then to magmas that may erupt, and how do these metals occur in the S-poor mantle? For our research, we will study three types of rocks; those that have been deeply subducted and brought back to the surface, pieces of mantle that were uplifted during mountain building, and mantle fragments that were brought to the surface by explosive volcanoes.