Behavior of chalcophile elements in subduction zones

俯冲带中亲铜元素的行为

• 批准号: 616-2009
• 负责人: Hattori, Keiko
• 金额: $ 3.5万
• 依托单位: University of Ottawa
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=568137
• 关键词: Behavior; chalcophile; elements; subduction; zones

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. The project will contribute to targeting the regions that may contain major metal deposits, and volcanoic regions that dangerously discharge SO2. Students participating to this project gain valuable research experience and theoretical and practical knowledge in geoscience that are not available in classrooms and useful in their career advances.

我将研究在弧火山形成的俯冲带中亲铜（类铜）元素的行为。这些元素与地壳浅层岩石中的硫有亲和力，包括我们社会所必需的许多金属，如铜。 大多数岩石主要由硅酸盐组成，亲铜元素仅以痕量浓度存在。具有开采经济价值的金属矿床出现在火山弧中，这些火山弧是在大洋岩石俯冲的地方形成的。金属矿床和俯冲带之间的这种空间联系表明了一种联系;然而，在俯冲导致岩石熔化从而导致弧火山作用的极深处，金属的行为却鲜为人知。在过去的研究中，我的团队已经表明，氧化的岩浆含有高浓度的硫和金属，氧化状态反映了底层地幔的性质。大量的SO2从Mt.菲律宾的皮纳图博火山是火山下地幔高度氧化的结果。我们在喜马拉雅山和南喜马拉雅山的工作也表明了这一点。地幔氧化条件受俯冲物质的影响。地幔含硫量低，需要从俯冲板块供给火山大量释放的硫。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的，以及这些金属是如何出现在贫硫地幔中的？在我们的研究中，我们将研究三种类型的岩石;那些已经被深深俯冲并带回地表的岩石，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。 该项目将有助于针对可能含有主要金属矿床的地区和危险排放二氧化硫的火山地区。参加该项目的学生获得了宝贵的研究经验和地球科学的理论和实践知识，这些知识在课堂上是无法获得的，对他们的职业发展很有用。