Collaborative Research: Rapid Magma Ascent Recorded in Volatile Diffusion Profiles

合作研究：挥发性扩散剖面记录的岩浆快速上升

• 批准号: 1524542
• 负责人: Terry Plank
• 金额: $ 30.76万
• 依托单位: Columbia University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1524542&HistoricalAwards=false
• 关键词: Collaborative; Research; Rapid; Magma; Ascent

Rapid Magma Ascent Recorded in Volatile Diffusion ProfilesWhat makes some eruptions more explosive than others? This fundamental questions is still largely unanswered, even after a given eruption has occurred. Theories link eruptive vigor to the amount of gas and stiffness of the magma, but magmas that have similar stiffness and gas-forming species can still erupt in a wide range of styles, some highly explosive, some quiescent. This project explores another fundamental parameter ? the rate at which magma rises in the volcanic conduit prior to eruption. The magma ascent rate will affect eruptive volume and vigor and also how bubbles form, grow and coalesce. In general, slow magma rise leads to more efficient bubble separation and less explosive eruption. This project aims to test the control of magma rise speed by extracting timescale information from erupted crystals and glass for several eruptions that span a range of exlosive magnitudes. This project will take advantage of new developments in using the zonation of volatile species in glass and crystals to obtain diffusive timescales that reflect ascent on the order of minutes to days prior to eruption. Four different chronometers will be used: 1) multi-species volatile diffusion through melt embayments, 2) water loss through olivine from melt inclusions of different sizes, 3) water zonation in olivine and clinopyroxene, and 4) zonation inside melt inclusions. Data will be obtained that derive from different microbeam techniques (NanoSIMS, FTIR, electron probe, laser ablation ICPMS) that record chemical zonation at the resolution of 5-25 microns. The proposed targets are a pair of well-documented eruptions from each of three volcanoes: Etna (2001 and 3930BP), Cerro Negro (1992 and 1995) and Paricutin (1943 and 1948), which span the range in mass eruption rates that characterize the transition from strombolian to subplinian styles. The eruptions targeted are specifically designed to test ideas as to the relationship between ascent rate and eruption rate in hydrous mafic magmas, among the most common but least well understood eruptions. This project will support a Ph.D. student and two high school interns from the Manhattan Center for Science and Mathematics, a public high school comprised largely of minority students from lower socioeconomic groups.

挥发性扩散剖面记录的岩浆快速上升是什么使一些喷发比其他喷发更具爆炸性？这个基本问题仍然在很大程度上没有答案，即使在特定的火山爆发发生后。理论将喷发的活力与岩浆的气体量和硬度联系起来，但是具有类似硬度和气体形成物种的岩浆仍然可以以各种各样的方式喷发，有些是高度爆炸性的，有些是静止的。这个项目探索了另一个基本参数？火山喷发前岩浆在火山管道中上升的速度。岩浆上升的速度会影响喷发的体积和活力，也会影响气泡的形成、生长和凝聚。一般来说，缓慢的岩浆上升导致更有效的气泡分离和更少的爆炸性喷发。该项目的目的是测试岩浆上升速度的控制，通过提取时间尺度的信息，从喷发的晶体和玻璃的几个爆发，跨越一个范围的exlosive量级。 该项目将利用玻璃和晶体中挥发性物质的分区的新发展，以获得反映喷发前几分钟至几天上升的扩散时间尺度。将使用四种不同的计时器：1）通过熔体海湾的多组分挥发分扩散，2）不同尺寸的熔体包裹体通过橄榄石的水分损失，3）橄榄石和单斜辉石中的水分分带，以及4）熔体包裹体内部的分带。将获得来自不同微束技术（NanoSIMS、FTIR、电子探针、激光消融ICPMS）的数据，这些微束技术以5-25微米的分辨率记录化学分区。拟议的目标是一对记录良好的喷发从三个火山：埃特纳（2001年和3930年BP），塞罗内格罗（1992年和1995年）和Pariclavia（1943年和1948年），其中跨越的范围内的大规模喷发率的特点从斯特龙博利亚到subplinian风格的过渡。所针对的喷发是专门设计来测试含水镁铁质岩浆的上升速率和喷发速率之间的关系的想法，这是最常见但最不了解的喷发之一。该项目将支持博士学位。一名学生和两名高中实习生来自曼哈顿科学和数学中心，这是一所公立高中，主要由来自较低社会经济群体的少数民族学生组成。