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Into a new caldera cycle: volcanic and magmatic evolution of Santorini volcano after the Late Bronze Age eruption

进入新的火山口循环：青铜时代晚期喷发后圣托里尼火山的火山和岩浆演化

基本信息

批准号：
NE/X016374/1
负责人：
Ralf Gertisser
金额：
$ 3.28万
依托单位：
Keele University
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FX016374%2F1
关键词：
Into new caldera cycle volcanic

项目摘要

From December 2022 to February 2023, Expedition 398 of the International Ocean Discovery Program will carry out a drilling campaign in the Christiana-Santorini-Kolumbo (CSK) volcanic field in the Aegean Sea of Greece, a particularly hazardous area because its volcanoes have produced many and highly explosive eruptions in the past.The proposed project focuses on Santorini, the largest volcanic centre of the CSK volcanic field and an iconic volcano because of its well-known eruption in the Late Bronze Age, also known as the Minoan eruption. This eruption was so powerful that it led to the collapse of the volcano, forming the flooded caldera, surrounded by the islands of Thera, Therasia and Aspronisi, and with the islands of Palaea and Nea Kameni - the surface expression of the Kameni volcano - in the centre, we see today.The Late Bronze Age eruption was not the only caldera-forming eruption on Santorini. In total, at least four calderas existed on Santorini in the past ~ 360 thousand years, showing the cyclicity of caldera-forming eruptions.Previous research led to considerable progress in our understanding of the assembly of magma and the timescales involved in the lead-up of these large-magnitude, caldera-forming eruptions at Santorini. By contrast, the transition from caldera-forming to post-caldera activity - or the renewed eruptive activity at the beginning of a caldera cycle - has remained largely unstudied. In case of the current caldera cycle, this is because the volcanic products from this activity are not exposed on land but lie beneath the seafloor within Santorini's caldera, therefore requiring research to move offshore.The proposed project aims to investigate the onset of the latest caldera cycle of Santorini following the caldera-forming eruption in the Late Bronze Age, using samples from two Expedition 398 drill sites in the Santorini caldera, which, for the first time, provide the opportunity to recover previously inaccessible volcanic products from post-Late-Bronze-Age volcanic activity of the Kameni volcano. In particular, the research will characterise (1) the eruptive activity, (2) the styles and frequency of eruptions, (3) the magma storage conditions, and (4) the magmatic processes that occur at depth inside the volcano and their timescales, at the onset and during the early stages of the current caldera cycle of Santorini volcano.The project aims will be achieved by macroscopic and microscopic drill core description, textural analysis of samples, and by characterising the geochemical composition, mineral content and other components of the magma(s) that fed the early, mainly submarine eruptions of the Kameni volcano, using a combination micro-textural analytical techniques, geochemical and petrological tools, and elemental diffusion chronometry applied to pyroxene, one of the main minerals in the eruptive products.The results will then be used to develop a conceptual framework for the magmatic processes and their timescales at the transition from caldera-forming to post-caldera volcanic activity and the beginning of a new caldera cycle at Santorini volcano.

从2022年12月到2023年2月，国际海洋发现计划的第398远征队将在希腊爱琴海的克里斯蒂安娜-圣托里尼-科龙博（CSK）火山区开展钻探活动，这是一个特别危险的地区，因为其火山过去曾产生过多次高爆炸性的喷发。拟议的项目重点是圣托里尼，CSK火山区最大的火山中心，也是一座标志性火山，因其在青铜时代晚期的著名喷发（也称为米诺斯喷发）而闻名。这次火山爆发的威力如此之大，导致火山崩溃，形成了被洪水淹没的破火山口，周围环绕着锡拉岛、锡拉西亚岛和阿斯普罗尼西岛，中心是帕莱亚岛和新卡梅尼岛--卡梅尼火山的地表表现。青铜时代晚期的火山爆发并不是圣托里尼岛上唯一形成破火山口的火山爆发。在过去的36万年里，圣托里尼岛上至少有4个破火山口，这表明破火山口形成的喷发具有周期性。以前的研究使我们对岩浆的聚集和圣托里尼岛这些大规模破火山口形成喷发的时间尺度的理解取得了相当大的进展。相比之下，从破火山口形成到破火山口后活动的过渡--或者说破火山口周期开始时的重新喷发活动--在很大程度上仍然没有得到研究。就目前的破火山口周期而言，这是因为这种活动的火山产物没有暴露在陆地上，而是位于圣托里尼破火山口内的海底之下，因此需要将研究转移到海上。拟议的项目旨在调查青铜时代晚期形成破火山口的火山爆发后，圣托里尼最新的破火山口周期的开始，使用来自圣托里尼火山口的两个398号勘探队钻探点的样本，这是第一次提供机会，从卡梅尼火山青铜时代晚期后的火山活动中恢复以前无法获得的火山产物。特别是，该研究将揭示（1）喷发活动，（2）喷发的类型和频率，（3）岩浆储存条件，（4）火山内部深处发生的岩浆过程及其时间尺度，在圣托里尼火山当前破火山口周期的开始和早期阶段。该项目的目标将通过宏观和微观岩心描述来实现。对样品进行结构分析，并通过综合使用微观结构分析技术、地球化学和岩石学工具以及对辉石应用的元素扩散测时法，确定卡梅尼火山早期主要是海底喷发的岩浆的地球化学成分、矿物含量和其他成分的特征，喷发产物中的主要矿物之一。研究结果将用于制定从破火山口形成到后期过渡的岩浆过程及其时间尺度的概念框架。火山活动和一个新的火山周期在圣托里尼火山的开始。