A regolith lead isoscape of Australia
<p>We present the first national-scale lead (Pb) isotope maps of Australia based on surface regolith for five isotope ratios, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="s...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2024-03-01
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| Series: | Earth System Science Data |
| Online Access: | https://essd.copernicus.org/articles/16/1383/2024/essd-16-1383-2024.pdf |
| _version_ | 1797261531988099072 |
|---|---|
| author | C. U. Desem P. de Caritat J. Woodhead R. Maas G. Carr |
| author_facet | C. U. Desem P. de Caritat J. Woodhead R. Maas G. Carr |
| author_sort | C. U. Desem |
| collection | DOAJ |
| description | <p>We present the first national-scale lead (Pb) isotope maps of Australia based on surface regolith for five isotope ratios, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="e2b4c152d04a98c71ee6378c00fe9403"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00001.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00001.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="00c58db6d3703defb753bdb5f603e392"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00002.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00002.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="66f6e34b561fbf86cfd77d9762478a32"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00003.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00003.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ce5d752788a0b117b55e8c8cb1d33bf0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00004.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00004.png"/></svg:svg></span></span>, and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="fa062e689928bc0d0a62d3c3ecf8be6f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00005.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00005.png"/></svg:svg></span></span>, determined by single-collector sector field inductively coupled plasma mass spectrometry after an ammonium acetate leach followed by aqua regia digestion. The dataset is underpinned principally by the National Geochemical Survey of Australia (NGSA) archived floodplain sediment samples. We analysed 1219 samples (0–10 cm depth, <span class="inline-formula"><2</span> mm grain size), collected near the outlet of 1119 large catchments covering <span class="inline-formula">5.647×10<sup>6</sup></span> km<span class="inline-formula"><sup>2</sup></span> (<span class="inline-formula">∼75 <i>%</i></span> of Australia). The samples consist of mixtures of the dominant soils and rocks weathering in their respective catchments (and possibly those upstream) and are therefore assumed to form a reasonable representation of the average isotopic signature of those catchments. This assumption was tested in one of the NGSA catchments, within which 12 similar samples were also taken; results show that the Pb isotope ratios of the NGSA catchment outlet sediment sample are close to the average of the 12 upstream sub-catchment samples. National minimum, median, and maximum values were 15.56, 18.84, and 30.64 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ffef8776b2534d28d46fc09984919165"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00006.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00006.png"/></svg:svg></span></span>; 14.36, 15.69, and 18.01 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="644cd8561e5fabd509e03b9c7d5b7978"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00007.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00007.png"/></svg:svg></span></span>; 33.56, 38.99, and 48.87 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="597ffcfe4a926395d9c735544f6e2663"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00008.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00008.png"/></svg:svg></span></span>; 0.5880, 0.8318, and 0.9847 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="42414e031fe5fe7c245916ca825b02e0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00009.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00009.png"/></svg:svg></span></span>; and 1.4149, 2.0665, and 2.3002 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ba0f204cb8b72f56ad0a775e2e560850"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00010.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00010.png"/></svg:svg></span></span>, respectively. The new dataset was compared with published bedrock and ore Pb isotope data, and it was found to dependably represent crustal elements of various ages from Archaean to Phanerozoic. This suggests that floodplain sediment samples are a suitable proxy for basement and basin geology at this scale, despite various degrees of transport, mixing, and weathering experienced in the regolith environment, locally over protracted periods of time. An example of atmospheric Pb contamination around Port Pirie, South Australia, where a Pb smelter has operated since the 1890s, is shown to illustrate potential environmental applications of this new dataset. Other applications may include elucidating details of Australian crustal evolution and mineralisation-related investigations. The new regolith Pb isotope dataset for Australia is publicly available (Desem et al., 2023; <a href="https://doi.org/10.26186/5ea8f6fd3de64">https://doi.org/10.26186/5ea8f6fd3de64</a>).</p> |
| first_indexed | 2024-04-24T23:42:42Z |
| format | Article |
| id | doaj.art-cc95f92a72f4445e9b0c616c978dc931 |
| institution | Directory Open Access Journal |
| issn | 1866-3508 1866-3516 |
| language | English |
| last_indexed | 2024-04-24T23:42:42Z |
| publishDate | 2024-03-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Earth System Science Data |
| spelling | doaj.art-cc95f92a72f4445e9b0c616c978dc9312024-03-15T11:06:09ZengCopernicus PublicationsEarth System Science Data1866-35081866-35162024-03-01161383139310.5194/essd-16-1383-2024A regolith lead isoscape of AustraliaC. U. Desem0P. de Caritat1J. Woodhead2R. Maas3G. Carr4School of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Melbourne, VIC 3010, AustraliaGeoscience Australia, GPO Box 378, Canberra, ACT 2601, AustraliaSchool of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Melbourne, VIC 3010, AustraliaSchool of Geography, Earth and Atmospheric Sciences, The University of Melbourne, Melbourne, VIC 3010, AustraliaCommonwealth Scientific and Industrial Research Organisation, North Ryde, NSW, Australia<p>We present the first national-scale lead (Pb) isotope maps of Australia based on surface regolith for five isotope ratios, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M1" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="e2b4c152d04a98c71ee6378c00fe9403"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00001.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00001.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="00c58db6d3703defb753bdb5f603e392"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00002.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00002.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="66f6e34b561fbf86cfd77d9762478a32"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00003.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00003.png"/></svg:svg></span></span>, <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M4" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ce5d752788a0b117b55e8c8cb1d33bf0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00004.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00004.png"/></svg:svg></span></span>, and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M5" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="fa062e689928bc0d0a62d3c3ecf8be6f"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00005.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00005.png"/></svg:svg></span></span>, determined by single-collector sector field inductively coupled plasma mass spectrometry after an ammonium acetate leach followed by aqua regia digestion. The dataset is underpinned principally by the National Geochemical Survey of Australia (NGSA) archived floodplain sediment samples. We analysed 1219 samples (0–10 cm depth, <span class="inline-formula"><2</span> mm grain size), collected near the outlet of 1119 large catchments covering <span class="inline-formula">5.647×10<sup>6</sup></span> km<span class="inline-formula"><sup>2</sup></span> (<span class="inline-formula">∼75 <i>%</i></span> of Australia). The samples consist of mixtures of the dominant soils and rocks weathering in their respective catchments (and possibly those upstream) and are therefore assumed to form a reasonable representation of the average isotopic signature of those catchments. This assumption was tested in one of the NGSA catchments, within which 12 similar samples were also taken; results show that the Pb isotope ratios of the NGSA catchment outlet sediment sample are close to the average of the 12 upstream sub-catchment samples. National minimum, median, and maximum values were 15.56, 18.84, and 30.64 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M10" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ffef8776b2534d28d46fc09984919165"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00006.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00006.png"/></svg:svg></span></span>; 14.36, 15.69, and 18.01 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M11" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="644cd8561e5fabd509e03b9c7d5b7978"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00007.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00007.png"/></svg:svg></span></span>; 33.56, 38.99, and 48.87 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M12" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">204</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="597ffcfe4a926395d9c735544f6e2663"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00008.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00008.png"/></svg:svg></span></span>; 0.5880, 0.8318, and 0.9847 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M13" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">207</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="42414e031fe5fe7c245916ca825b02e0"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00009.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00009.png"/></svg:svg></span></span>; and 1.4149, 2.0665, and 2.3002 for <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M14" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">208</mn></msup><mi mathvariant="normal">Pb</mi><msup><mo>/</mo><mn mathvariant="normal">206</mn></msup><mi mathvariant="normal">Pb</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="63pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="ba0f204cb8b72f56ad0a775e2e560850"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="essd-16-1383-2024-ie00010.svg" width="63pt" height="15pt" src="essd-16-1383-2024-ie00010.png"/></svg:svg></span></span>, respectively. The new dataset was compared with published bedrock and ore Pb isotope data, and it was found to dependably represent crustal elements of various ages from Archaean to Phanerozoic. This suggests that floodplain sediment samples are a suitable proxy for basement and basin geology at this scale, despite various degrees of transport, mixing, and weathering experienced in the regolith environment, locally over protracted periods of time. An example of atmospheric Pb contamination around Port Pirie, South Australia, where a Pb smelter has operated since the 1890s, is shown to illustrate potential environmental applications of this new dataset. Other applications may include elucidating details of Australian crustal evolution and mineralisation-related investigations. The new regolith Pb isotope dataset for Australia is publicly available (Desem et al., 2023; <a href="https://doi.org/10.26186/5ea8f6fd3de64">https://doi.org/10.26186/5ea8f6fd3de64</a>).</p>https://essd.copernicus.org/articles/16/1383/2024/essd-16-1383-2024.pdf |
| spellingShingle | C. U. Desem P. de Caritat J. Woodhead R. Maas G. Carr A regolith lead isoscape of Australia Earth System Science Data |
| title | A regolith lead isoscape of Australia |
| title_full | A regolith lead isoscape of Australia |
| title_fullStr | A regolith lead isoscape of Australia |
| title_full_unstemmed | A regolith lead isoscape of Australia |
| title_short | A regolith lead isoscape of Australia |
| title_sort | regolith lead isoscape of australia |
| url | https://essd.copernicus.org/articles/16/1383/2024/essd-16-1383-2024.pdf |
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