<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD Journal Publishing DTD v3.0 20080202//EN" "https://jats.nlm.nih.gov/nlm-dtd/publishing/3.0/journalpublishing3.dtd">
<article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article" specific-use="SMUR" dtd-version="3.0" xml:lang="en">
<front>
<journal-meta>
<journal-id journal-id-type="publisher">EGUsphere</journal-id>
<journal-title-group>
<journal-title>EGUsphere</journal-title>
<abbrev-journal-title abbrev-type="publisher">EGUsphere</abbrev-journal-title>
<abbrev-journal-title abbrev-type="nlm-ta">EGUsphere</abbrev-journal-title>
</journal-title-group>
<issn pub-type="epub"></issn>
<publisher><publisher-name>Copernicus Publications</publisher-name>
<publisher-loc>Göttingen, Germany</publisher-loc>
</publisher>
</journal-meta>
<article-meta>
<article-id pub-id-type="doi">10.5194/egusphere-2025-355</article-id>
<title-group>
<article-title>New evidence on the microstructural localization of sulfur, chlorine &amp;amp; sodium in polar ice cores with implications for impurity diffusion</article-title>
</title-group>
<contrib-group><contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Bohleber</surname>
<given-names>Pascal</given-names>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff2">
<sup>2</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Stoll</surname>
<given-names>Nicolas</given-names>
<ext-link>https://orcid.org/0000-0002-3219-8395</ext-link>
</name>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Larkman</surname>
<given-names>Piers</given-names>
<ext-link>https://orcid.org/0000-0002-5374-7349</ext-link>
</name>
<xref ref-type="aff" rid="aff1">
<sup>1</sup>
</xref>
<xref ref-type="aff" rid="aff3">
<sup>3</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Rhodes</surname>
<given-names>Rachael H.</given-names>
<ext-link>https://orcid.org/0000-0001-7511-1969</ext-link>
</name>
<xref ref-type="aff" rid="aff4">
<sup>4</sup>
</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple"><name name-style="western"><surname>Clases</surname>
<given-names>David</given-names>
<ext-link>https://orcid.org/0000-0003-3880-9385</ext-link>
</name>
<xref ref-type="aff" rid="aff5">
<sup>5</sup>
</xref>
</contrib>
</contrib-group><aff id="aff1">
<label>1</label>
<addr-line>Alfred Wegener Institute Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany</addr-line>
</aff>
<aff id="aff2">
<label>2</label>
<addr-line>Goethe University Frankfurt am Main, Frankfurt am Main, Germany</addr-line>
</aff>
<aff id="aff3">
<label>3</label>
<addr-line>Ca’ Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Italy</addr-line>
</aff>
<aff id="aff4">
<label>4</label>
<addr-line>Department of Earth Sciences, University of Cambridge, Cambridge, UK</addr-line>
</aff>
<aff id="aff5">
<label>5</label>
<addr-line>Nano Micro LAB, Institute of Chemistry, University of Graz, Graz, Austria</addr-line>
</aff>
<pub-date pub-type="epub">
<day>05</day>
<month>03</month>
<year>2025</year>
</pub-date>
<volume>2025</volume>
<fpage>1</fpage>
<lpage>20</lpage>
<permissions>
<copyright-statement>Copyright: &#x000a9; 2025 Pascal Bohleber et al.</copyright-statement>
<copyright-year>2025</copyright-year>
<license license-type="open-access">
<license-p>This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit <ext-link ext-link-type="uri"  xlink:href="https://creativecommons.org/licenses/by/4.0/">https://creativecommons.org/licenses/by/4.0/</ext-link></license-p>
</license>
</permissions>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-355/">This article is available from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-355/</self-uri>
<self-uri xlink:href="https://egusphere.copernicus.org/preprints/2025/egusphere-2025-355/egusphere-2025-355.pdf">The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2025/egusphere-2025-355/egusphere-2025-355.pdf</self-uri>
<abstract>
<p>Aerosol-related impurities play an important part in the set of paleoclimate proxies obtained from polar ice cores. However, in order to avoid misinterpretation, post-depositional changes need to be carefully assessed, especially in deep ice. Na, S and Cl are among the relatively abundant impurity species in polar ice (albeit still at the low ppb level in bulk samples), with important applications to paleoclimate reconstructions and dating, e.g. via identification of volcanic eruptions. Especially S has been studied intensely with respect to peak broadening with depth/age related to diffusion, but the precise physical mechanisms remain unclear. Mapping the two-dimensional impurity distribution in ice with laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) has shown great potential for studying ice-impurity interactions, but the analytically more challenging elements S and Cl have not been targeted thus far. We show here that signals of S and Cl can be detected in Greenland and Antarctic ice not containing enhanced concentrations resulting from a volcanic eruption, by using LA-ICP-MS to obtain multi-elemental maps at high resolution up to 10 &amp;micro;m and, exemplarily even 1 &amp;micro;m. We find a high level of localization of S and Cl (and Na) at grain boundaries but also some dispersed occurrence within grain interiors in dust-rich ice. The new maps support a view on diffusive transport not only through ice veins but also along grain boundaries, but do not show any clear differences in this regard between samples from the Holocene and last glacial period in the EDC ice core. The results extend early studies targeting the localization of impurities, in particular S and Cl, and highlight the benefit of integrating such direct measurements with modelling efforts to determine the physical processes behind impurity diffusion.</p>
</abstract>
<counts><page-count count="20"/></counts>
<funding-group>
<award-group id="gs1">
<funding-source>H2020 Marie Skłodowska-Curie Actions</funding-source>
<award-id>101018266</award-id>
</award-group>
<award-group id="gs2">
<funding-source>European Research Council</funding-source>
<award-id>101088125</award-id>
</award-group>
</funding-group>
</article-meta>
</front>
<body/>
<back>
</back>
</article>