Evaluation of crustal recycling and magma formation by subduction in the Trans Mexican Volcanic Belt: New insights from the Ceboruco volcano, Mexico

跨墨西哥火山带俯冲作用的地壳循环和岩浆形成评估：墨西哥塞博鲁科火山的新见解

• 批准号: 2902362
• 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-2902362
• 关键词: Evaluation; crustal; recycling; magma; formation

The Trans-Mexican Volcanic Belt (TMVB) is one of the most compositionally diverse magmatic arcs on Earth and therefore constitutes a prime location for testing emerging hypotheses on arc petrogenesis and continental evolution (Gómez-Tuena et al., 2018). Recycling of upper plate crust in subduction zones, or 'subduction erosion', is a major mechanism of crustal destruction at convergent margins. Assessing the impact of eroded crust on arc magmas is, however, difficult owing to the compositional similarity between the eroded crust, trench sediment and arc crustal basement that may all contribute to arc magma formation (Ferrari et al., 2011; Straub et al., 2015). Ceboruco volcano is one of a few active volcanoes in the western part of the TMVB and is compositionally diverse ranging from mafic to rhyolite magmas (Nelson, 1980; Nunez et al., 2022). It is known that Ceboruco produced three compositionally and volumetrically different magma types including two caldera-forming explosive eruptions. However, it remains unclear how these different magmas formed, what controls their composition including distinctively high-Nb magmas enriched in LILE and HFSE resembling those of enriched intraplate magmas. Volatile bearing minerals, common to other volcanoes within the TMVB, are rare at Ceboruco raising the question whether metasomatism can be held responsible for this enrichment? This project will focus on a field-based analysis of the volcano and geochemical and petrographic study of samples collected from various domes and lavas in order to gain a better understanding leading to the formation of a range of volcanic products. The aim is to create a schematic model of the Ceboruco magma system and to see whether the basaltic to rhyolitic magmas originated from the same reservoir or whether complex processes involving partial melting of different source regions, fractional crystallisation and magma mixing and/or crustal erosion was responsible for the diverse magmatism at Ceboruco. In order to achieve this, whole rock and in-situ analyses of the mineral budget will be applied and compared to data from other subduction zone volcanoes to outline a potential magmatic system for Ceboruco. This combination provides a unique opportunity to track the eruption history of subduction-related volcanism and magma enrichment processes.

跨墨西哥火山带（TMVB）是地球上成分最多样化的岩浆弧之一，因此构成了测试弧岩石成因和大陆演化新假说的主要地点（Gómez-Tuena等人，2018年）。板块上部地壳在俯冲带的再循环，或称“俯冲侵蚀”，是会聚边缘地壳破坏的主要机制。然而，评估侵蚀地壳对弧岩浆的影响是困难的，因为侵蚀地壳、海沟沉积物和弧地壳基底之间的成分相似，可能都有助于弧岩浆的形成（Ferrari等人，2011; Straub等人，2015年）。Ceboruco火山是TMVB西部少数几个活火山之一，其成分多样，从镁铁质到流纹岩岩浆不等（纳尔逊，1980年; Nunez等人，2022年）。据了解，Ceboruco产生了三种成分和体积不同的岩浆类型，包括两个破火山口形成的爆炸性喷发。然而，目前还不清楚这些不同的岩浆是如何形成的，是什么控制了它们的成分，包括独特的高铌岩浆富集LILE和HFSE类似的富集板内岩浆。挥发性矿物，常见的其他火山在TMVB，是罕见的Ceboruco提出的问题，是否交代可以负责这种富集？该项目将侧重于对火山进行实地分析，并对从各种穹丘和熔岩中收集的样本进行地球化学和岩相学研究，以便更好地了解各种火山产物的形成。其目的是创建一个示意图模型的Ceboruco岩浆系统，看看是否玄武流纹岩岩浆起源于同一个水库或复杂的过程，涉及不同的源区，部分结晶和岩浆混合和/或地壳侵蚀的部分熔融是负责不同的岩浆在Ceboruco。为了实现这一目标，将应用矿物预算的全岩和现场分析，并与其他俯冲带火山的数据进行比较，以概述Ceboruco潜在的岩浆系统。这种组合提供了一个独特的机会，以跟踪喷发历史的俯冲有关的火山作用和岩浆富集过程。