Bubbles in Youngest Toba Tuff melt inclusions reveal pre-eruptive magma vesicularity and perhaps why the eruption was so big

IF 2.3 3区地球科学 Q2 GEOSCIENCES, MULTIDISCIPLINARY

Journal of Volcanology and Geothermal Research Pub Date : 2026-04-01 Epub Date: 2026-01-30 DOI:10.1016/j.jvolgeores.2026.108556

Tyler Cadena, Michael Manga, Stephen Self

{"title":"Bubbles in Youngest Toba Tuff melt inclusions reveal pre-eruptive magma vesicularity and perhaps why the eruption was so big","authors":"Tyler Cadena, Michael Manga, Stephen Self","doi":"10.1016/j.jvolgeores.2026.108556","DOIUrl":null,"url":null,"abstract":"<div><div>The 75 ka eruption of the Youngest Toba Tuff is one of few eruptions proposed to be initiated by volatile accumulation, a seldom identified eruption initiation mechanism in large silicic systems. We searched for evidence of pre-eruptive exsolved volatiles in the erupted products of the Youngest Toba Tuff by using x-ray microtomography to image six quartz crystals, which contain populous bubbly melt inclusions. Analysis of 84 melt inclusions show an average of 8.6 bubble vol.% and 2.2 bubbles (maximum 11 bubbles) per inclusion. We find that 70% of inclusions have a bubble vol.% greater than 3, the maximum vol.% that could be caused by post-entrapment bubble growth, implying that these bubbly inclusions sampled an at-depth exsolved vapor phase that was co-entrapped with the melt. These physical observations support previous chemical analyses that suggest the eruption of the Youngest Toba Tuff was initiated by volatile accumulation. Using our vesicularity measurements and models for compressibility of multiphase materials, the exsolved vapor phase can increase magma compressibility by an order of magnitude. These changes in magma compressibility can promote especially large eruptions such as that responsible for the Youngest Toba Tuff.</div></div>","PeriodicalId":54753,"journal":{"name":"Journal of Volcanology and Geothermal Research","volume":"472 ","pages":"Article 108556"},"PeriodicalIF":2.3000,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Volcanology and Geothermal Research","FirstCategoryId":"89","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0377027326000296","RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2026/1/30 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"GEOSCIENCES, MULTIDISCIPLINARY","Score":null,"Total":0}

引用次数: 0

Abstract

The 75 ka eruption of the Youngest Toba Tuff is one of few eruptions proposed to be initiated by volatile accumulation, a seldom identified eruption initiation mechanism in large silicic systems. We searched for evidence of pre-eruptive exsolved volatiles in the erupted products of the Youngest Toba Tuff by using x-ray microtomography to image six quartz crystals, which contain populous bubbly melt inclusions. Analysis of 84 melt inclusions show an average of 8.6 bubble vol.% and 2.2 bubbles (maximum 11 bubbles) per inclusion. We find that 70% of inclusions have a bubble vol.% greater than 3, the maximum vol.% that could be caused by post-entrapment bubble growth, implying that these bubbly inclusions sampled an at-depth exsolved vapor phase that was co-entrapped with the melt. These physical observations support previous chemical analyses that suggest the eruption of the Youngest Toba Tuff was initiated by volatile accumulation. Using our vesicularity measurements and models for compressibility of multiphase materials, the exsolved vapor phase can increase magma compressibility by an order of magnitude. These changes in magma compressibility can promote especially large eruptions such as that responsible for the Youngest Toba Tuff.

Abstract Image

查看原文本刊更多论文

最年轻的鸟羽凝灰岩熔体包裹体中的气泡揭示了喷发前的岩浆泡状，这也许是火山喷发如此之大的原因

最年轻的多巴凝灰岩的75 ka喷发是为数不多的由挥发性堆积引发的喷发之一，这是大型硅质体系中很少发现的喷发启动机制。我们利用x射线显微断层摄影技术对6个石英晶体进行了成像，寻找最年轻的多巴凝灰岩喷发产物中喷发前挥发物的证据，这些石英晶体含有大量的气泡熔融包裹体。对84个熔体夹杂物的分析表明，平均每个夹杂物有8.6个气泡体积%和2.2个气泡（最大11个气泡）。我们发现70%的包裹体的气泡体积%大于3，这是由包裹后气泡生长引起的最大体积%，这意味着这些泡状包裹体取样了与熔体共包裹的深度溶解气相。这些物理观察结果支持了先前的化学分析，即最年轻的多巴凝灰岩的喷发是由挥发性积累引起的。利用我们对多相物质的可压缩性的泡度测量和模型，发现溶解的蒸汽相可以使岩浆的可压缩性提高一个数量级。岩浆可压缩性的这些变化可以促进特别大的喷发，比如最年轻的多巴凝灰岩。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Journal of Volcanology and Geothermal Research 地学-地球科学综合

CiteScore

5.90

自引率

13.80%

发文量

183

审稿时长

19.7 weeks

期刊介绍： An international research journal with focus on volcanic and geothermal processes and their impact on the environment and society. Submission of papers covering the following aspects of volcanology and geothermal research are encouraged: (1) Geological aspects of volcanic systems: volcano stratigraphy, structure and tectonic influence; eruptive history; evolution of volcanic landforms; eruption style and progress; dispersal patterns of lava and ash; analysis of real-time eruption observations. (2) Geochemical and petrological aspects of volcanic rocks: magma genesis and evolution; crystallization; volatile compositions, solubility, and degassing; volcanic petrography and textural analysis. (3) Hydrology, geochemistry and measurement of volcanic and hydrothermal fluids: volcanic gas emissions; fumaroles and springs; crater lakes; hydrothermal mineralization. (4) Geophysical aspects of volcanic systems: physical properties of volcanic rocks and magmas; heat flow studies; volcano seismology, geodesy and remote sensing. (5) Computational modeling and experimental simulation of magmatic and hydrothermal processes: eruption dynamics; magma transport and storage; plume dynamics and ash dispersal; lava flow dynamics; hydrothermal fluid flow; thermodynamics of aqueous fluids and melts. (6) Volcano hazard and risk research: hazard zonation methodology, development of forecasting tools; assessment techniques for vulnerability and impact.