Two-dimensional impurity imaging in deep Antarctic ice cores: snapshots of three climatic periods and implications for high-resolution signal interpretation

Due to its micrometer-scale resolution and inherently micro-destructive nature, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is particularly suited to exploring the thin and closely spaced layers in the oldest sections of polar ice cores. Recent adaptions to the LA-ICP-MS...

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Bibliographic Details
Published in:The Cryosphere
Main Authors: P. Bohleber, M. Roman, M. Ε ala, B. Delmonte, B. Stenni, C. Barbante
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2021
Subjects:
Environmental sciences
GE1-350
Geology
QE1-996.5
Antarctic
Talos Dome
Antarc*
Antarctica
EPICA
ice core
The Cryosphere
Online Access:https://doi.org/10.5194/tc-15-3523-2021
https://doaj.org/article/a89b79b45b4b43d6a8609dc0923ba159
Description
Summary:Due to its micrometer-scale resolution and inherently micro-destructive nature, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is particularly suited to exploring the thin and closely spaced layers in the oldest sections of polar ice cores. Recent adaptions to the LA-ICP-MS instrumentation mean we have faster washout times allowing state-of-the-art 2-D imaging of an ice core. This new method has great potential especially when applied to the localization of impurities on the ice sample, something that is crucial, to avoiding misinterpretation of the ultra-fine-resolution signals. Here we present the first results of the application of LA-ICP-MS elemental imaging to the analysis of selected glacial and interglacial samples from the Talos Dome and EPICA Dome C ice cores from central Antarctica. The localization of impurities from both marine and terrestrial sources is discussed, with special emphasis on observing a connection with the network of grain boundaries and differences between different climatic periods. Scale-dependent image analysis shows that the spatial significance of a single line profile along the main core axis increases systematically as the imprint of the grain boundaries weakens. It is demonstrated how instrumental settings can be adapted to suit the purpose of the analysis, i.e., by either employing LA-ICP-MS to study the interplay between impurities and the ice microstructure or to investigate the extremely thin climate proxy signals in deep polar ice.

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