Time scales of syneruptive volatile loss in silicic magmas quantified by Li isotopes

被引：1

作者：

Neukampf, J. ^{[1
]}

Ellis, B. S. ^{[1
]}

Laurent, O. ^{[1
,2
]}

Steinmann, L. K. ^{[3
]}

Ubide, T. ^{[4
]}

Oeser, M. ^{[3
]}

Magna, T. ^{[5
]}

Weyer, S. ^{[3
]}

Bachmann, O. ^{[1
]}

机构：

[1] Swiss Fed Inst Technol, Inst Geochem & Petrol, CH-8092 Zurich, Switzerland

[2] Observ Midi Pyrenees, Geosci Environm Toulouse, CNRS, F-31400 Toulouse, France

[3] Leibniz Univ Hannover, Inst Mineral, D-30167 Hannover, Germany

[4] Univ Queensland, Sch Earth & Environm Sci, Brisbane, Qld 4072, Australia

[5] Czech Geol Survey, CZ-11821 Prague, Czech Republic

来源：

GEOLOGY | 2021年 / 49卷 / 02期

基金：

瑞士国家科学基金会;

关键词：

FRACTIONATION; EVOLUTION; DIFFUSION; LITHIUM; MELT; PLAGIOCLASE; INCLUSIONS; OLIVINE; GROWTH; ASCENT;

D O I：

10.1130/G47764.1

中图分类号：

P5 [地质学];

学科分类号：

0709 ; 081803 ;

摘要：

Most explosive, silicic volcanoes spend thousands of years in repose between eruptive events. The timing of the switch from repose to eruption is key to interpreting monitoring signals and improving the safety of people living close to active volcanoes. We addressed this question using a novel technique based on lithium isotopic (delta Li-7) and elemental concentration profiles within plagioclase crystals from the Mesa Falls Tuff of the Yellowstone volcanic system (Idaho and Wyoming, USA), constraining volatile degassing to occur on minimum time scales of tens of minutes prior to eruption. During this ephemeral time, Li abundances drop by a factor of four to 10 from crystal cores to rims, accompanied by an increase in delta Li-7 of as much as 10 parts per thousand, reflecting diffusion-driven equilibration between plagioclase cores and outgassed, Li-poor melt. New times scales obtained in this study show the potential for rapid syneruptive changes in the volatile inventory of magmas.

引用

页码：125 / 129

页数：5