Correlation and characterisation of individual glass shards from tephra deposits using trace element laser ablation ICP‐MS analyses: current status and future potential

Abstract

Pearce, Nicholas, Denton, J.S., Perkins, W.T., Westgate, J.A., (2007) 'Correlation and characterisation of individual glass shards from tephra deposits using trace element laser ablation ICP-MS analyses: current status and future potential', Journal of Quaternary Science 22(7) pp.721-736 RAE2008Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a high spatial resolution analytical method which has been applied to the analysis of silicic tephras. With current instrumentation, around 30 trace elements can be determined from single glass shards as small as 40 ?m, separated from tephra deposits. As a result of element fractionation during the ablation process using a 266 nm laser, a relatively complex calibration strategy is required. Nonetheless, such a strategy gives analyses which are accurate (typically within ?5%) and have an analytical precision which varies from ?2% at 100 ppm, to ?15% at 1 ppm. Detection limits for elements used in correlation and discrimination studies are well below 1 ppm. Examples of the application of trace element analysis by LA-ICP-MS in tephra studies are presented from the USA, New Zealand and the Mediterranean. Improvements in instrumental sensitivity in recent years have the potential to lower detection limits and improve analytical precision, thus allowing the analysis of smaller glass shards from more distal tephras. Laser systems operating at shorter wavelengths (e.g. 193 nm) are now more widely available, and produce a much more controllable ablation in glasses than 266 nm lasers. Crater sizes ofPeer reviewe

Source of the great A.D. 1257 mystery eruption unveiled, Samalas volcano, Rinjani Volcanic Complex, Indonesia

“…For all other major elements, the difference varies from a minimum of 0.03-1.08 (Table S2). Pearce et al (37,38) have shown that positive matching of source with distal tephra requires the difference in composition to be ≤1-2% for SiO 2 and Al 2 O 3 , and ≤5-10% for all other elements, therefore pointing to a very strong correlation between volcanic glass of the F1, F2, and F3 units of Samalas and the 1258/1259 ice-core tephra, with 1-σ error bars crossing each other for the eight major oxides.…”

Tephrochronology and its application: A review

“…Where mineralogical and major-element data are unavailable, or prove insufficient or equivocal, then the next step is to obtain analyses on glass of trace and rare-earth elements (REEs) (Pearce et al, 2002(Pearce et al, , 2007Knott et al, 2007;Allan et al, 2008;Turney et al, 2008;Kuehn et al, 2009). A recent example of such a situation is that for the Sheep Creek group of tephras in western Canada and Alaska as described by Westgate et al (2008).…”

Geochemical signatures of tephras from Quaternary Antarctic Peninsula volcanoes

“…deposits (Alloway et al, 2007;Pearce et al, 2007;Lowe, 2008Lowe, , 2011. However, not every volcanic center or volcanic eruption creates globally distributed tephra layers.…”

“…However, not every volcanic center or volcanic eruption creates globally distributed tephra layers. Several regional tephrochronological frameworks have been established in the last decade, e.g., for Europe (Turney et al, 2004;Newton et al, 2007;Lane et al, 2011Lane et al, , 2012 and New Zealand (Alloway et al, 2007), as well as some databases that include a wider variety of volcanic and igneous rocks. A number of regional database projects, including Tephrabase, NAVDAT, Central Andes, GeoMapApp, and GEOROC, implement data storage and availability for specific geographical regions.…”

“…Recent studies in other regions (Alloway et al, 2007;Pearce et al, 2007) demonstrate that trace element signatures could provide a unique chemical 'fingerprint' for individual volcanic centers, because trace elements tend to vary more strongly between different volcanoes than major elements do, refining considerably the resulting geochemical information.…”