Shallow sampling by multi-shot laser ablation and its application within U-Pb zircon geochronology
Item Type:Journal Article
Citation:Corbett, E.P., Simonetti, A., Shaw, P., Corcoran, L., Crowley, Q.G. & Hoare, B.C., Shallow sampling by multi-shot laser ablation and its application within U-Pb zircon geochronology, Chemical Geology, 2020
Multi-shot LA-ICP-MS (Eoghan Corbett).pdf (Published (author's copy) - Peer Reviewed) 12.64Mb
The interaction of incident laser radiation and sample substrate is complex and difficult to predict. Natural zircons are often both structurally and chemically heterogeneous in 3-dimensional space. Encountering growth-related, structural micro-heterogeneities, inclusions and chemical complexities is almost inevitable during a static ablation of several tens of seconds. A multi-shot approach to laser ablation described here implements a minimal sample exposure time to incident laser radiation by applying multiple 1 Hz shots to a single sample location in delayed succession. This process can be conceptualised as a “slowing down” of a high-frequency (5–20 Hz) static laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analysis until each laser pulse is distinct albeit transient. The ability to integrate and collate signal pulses for a small number of consecutive laser shots, as opposed to continuously pulsing the laser, produces precise age determinations (~1% reproducibility, 2σ level) on small sample volumes (698 ± 22 μm3 on 91500 zircon standard). The multi-shot LA-ICP-MS protocol employed here significantly reduces the effect of ‘downhole’ fractionation as the resultant craters are extremely shallow (as shallow as 0.56 ± 0.02 μm on 91500 zircon standard) and maintain an aspect ratio of ≪1. Further benefits include a reduced probability of thermally induced effects (e.g., substrate melting), plasma loading, and the potential for signal mixing (with depth) in a heterogeneous sample.
Author: Crowley, Quentin; Corbett, Eoghan P.; Simonetti, Antonio; Shaw, Phil; Corcoran, Loretta; Hoare, Brendan C.
Type of material:Journal Article
Series/Report no:Chemical Geology;
Availability:Full text available
Keywords:Low sample volum, Multi-shot LA-ICP-MS, Sub-micron sampling, Depth resolution, Downhole fractionation, LIEF
Subject (TCD):Nanoscience & Materials , Smart & Sustainable Planet , Mass Spectrometry , U-PB GEOCHRONOLOGY , ZIRCONS