Relating changes in melt genesis to dynamic conditions of the demise of a continental arc: Antarctic Peninsula arc

将融化成因的变化与大陆弧消亡的动态条件联系起来：南极半岛弧

• 批准号: 2899697
• 金额: --
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2899697
• 关键词: Relating; changes; melt; genesis; dynamic

The poorly understood Antarctic Peninsula volcanic arc was an active continental margin between the Early Late Jurassic and the Early Miocene. Although many expeditions have visited parts of the arc, and the northern end of the arc has been well-studied, there are vast tracts of the arc for which there are either no geochronological constraints or geochemical investigations of the arc development. A recent study of the available data (Leat and Riley, 2018) found four chemically distinct volcanic groups within the arc: calc-alkaline, high-Mg andesites, adakites and a peralkaline high-Zr group. However, few constraints between the groups are known, including their timing within arc development and their relation to each other, and what their significance was to the changing margin dynamics of the time. The Leat and Riley (2018) study has highlighted the perhaps unusual feature of numerous high-Mg andesites within the arc, but the significance of this is uncertain due to a lack of geochronological controls. A migration of the arc toward the trench is indicated to have occurred during the Cretaceous, but is also very poorly constrained due to the lack of age data. New isotopic ages will constrain the changing melt conditions along and across the arc and will be linked into the development of geodynamic models for the area.This project will take advantage of the exceptional collection of samples held by the British Antarctic Survey and access to it through BAS scientist Dr Riley. Furthermore, the link between UoL and BAS will be enhanced by two honorary Leicester scientists Drs Leat and Smellie who have formerly been BAS-scientists and whom collected many of the legacy samples. The aim of this project will be to learn how the high-Mg andesites and adakites fit into the development of the Antarctic Peninsula arc, what the controls their genesis, and what this tells us about the changing conditions of melt production along the Antarctic Peninsula arc during its life cycle of development and demise.The project will suit a student interested in geochemistry and geochronology, taking apart a poorly explored region, and with a keen interest in petrogenesis and arc magmatism.

人们知之甚少的南极半岛火山弧是晚侏罗世早期和早中新世之间的活跃大陆边缘。尽管许多探险队已经访问了弧的部分地区，并且对弧的北端进行了深入研究，但弧的大片区域要么没有地质年代学限制，要么没有对弧发育进行地球化学调查。最近对现有数据的一项研究（Leat 和 Riley，2018）发现弧内有四个化学性质不同的火山群：钙碱性、高镁安山岩、埃达克岩和过碱性高锆岩群。然而，人们对这些群体之间的限制知之甚少，包括它们在弧发展中的时间安排、它们之间的关系，以及它们对当时不断变化的边缘动态的重要性。 Leat 和 Riley（2018）的研究强调了弧内众多高镁安山岩可能不寻常的特征，但由于缺乏地质年代学控制，其重要性尚不确定。表明弧向海沟的迁移发生在白垩纪期间，但由于缺乏年龄数据，限制也很差。新的同位素年龄将限制沿弧线和跨弧线融化条件的变化，并将与该地区地球动力学模型的开发联系起来。该项目将利用英国南极调查局拥有的特殊样本收集，并通过 BAS 科学家 Riley 博士获取这些样本。此外，两位莱斯特大学荣誉科学家 Leat 和 Smellie 博士将加强伦敦大学学院和 BAS 之间的联系，他们曾是 BAS 科学家，收集了许多遗留样本。该项目的目的是了解高镁安山岩和埃达克岩如何适应南极半岛弧的发展，控制其成因的因素，以及这告诉我们在其发展和消亡生命周期中，南极半岛弧沿熔体生产条件的变化。该项目适合对地球化学和地质年代学感兴趣、对勘探程度较低的地区进行分解并对岩石成因有浓厚兴趣的学生 和弧岩浆作用。