Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys
<p>Here, we present cosmogenic-<span class="inline-formula"><sup>10</sup></span>Be and cosmogenic-<span class="inline-formula"><sup>3</sup></span>He data from Ferrar dolerite pyroxenes in surficial rock samples and a bedrock c...
| Main Authors: | , , , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2023-07-01
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| Series: | Geochronology |
| Online Access: | https://gchron.copernicus.org/articles/5/301/2023/gchron-5-301-2023.pdf |
| _version_ | 1797256806359105536 |
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| author | A. Balter-Kennedy A. Balter-Kennedy J. M. Schaefer J. M. Schaefer R. Schwartz J. L. Lamp L. Penrose J. Middleton J. Hanley B. Tibari P.-H. Blard G. Winckler G. Winckler A. J. Hidy G. Balco |
| author_facet | A. Balter-Kennedy A. Balter-Kennedy J. M. Schaefer J. M. Schaefer R. Schwartz J. L. Lamp L. Penrose J. Middleton J. Hanley B. Tibari P.-H. Blard G. Winckler G. Winckler A. J. Hidy G. Balco |
| author_sort | A. Balter-Kennedy |
| collection | DOAJ |
| description | <p>Here, we present cosmogenic-<span class="inline-formula"><sup>10</sup></span>Be and cosmogenic-<span class="inline-formula"><sup>3</sup></span>He data
from Ferrar dolerite pyroxenes in surficial rock samples and a bedrock core
from the McMurdo Dry Valleys, Antarctica, with the goal of refining the
laboratory methods for extracting beryllium from pyroxene, further
estimating the <span class="inline-formula"><sup>10</sup></span>Be production rate in pyroxene and demonstrating the
applicability of <span class="inline-formula"><sup>10</sup></span>Be–<span class="inline-formula"><sup>3</sup></span>He in mafic rock. The ability to routinely
measure cosmogenic <span class="inline-formula"><sup>10</sup></span>Be in pyroxene will open new opportunities for
quantifying exposure durations and Earth surface processes in mafic rocks.
We describe scalable laboratory methods for isolating beryllium from
pyroxene, which include a simple hydrofluoric acid leaching procedure for
removing meteoric <span class="inline-formula"><sup>10</sup></span>Be and the addition of a pH 8 precipitation step
to reduce the cation load prior to ion exchange chromatography. <span class="inline-formula"><sup>10</sup></span>Be
measurements in pyroxene from the surface samples have apparent <span class="inline-formula"><sup>3</sup></span>He
exposure ages of 1–6 Myr. We estimate a spallation production rate for
<span class="inline-formula"><sup>10</sup></span>Be in pyroxene, referenced to <span class="inline-formula"><sup>3</sup></span>He, of 3.6 <span class="inline-formula">±</span> 0.2 atoms g<span class="inline-formula"><sup>−1</sup></span> yr<span class="inline-formula"><sup>−1</sup></span>. <span class="inline-formula"><sup>10</sup></span>Be and <span class="inline-formula"><sup>3</sup></span>He measurements in the bedrock core
yield initial estimates for parameters associated with <span class="inline-formula"><sup>10</sup></span>Be and
<span class="inline-formula"><sup>3</sup></span>He production by negative-muon capture (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi>f</mi><mn mathvariant="normal">10</mn><mo>∗</mo></msubsup><mo>=</mo><mn mathvariant="normal">0.00183</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="67pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b8d80758c5229555d2f87ecc0009ae48"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gchron-5-301-2023-ie00001.svg" width="67pt" height="14pt" src="gchron-5-301-2023-ie00001.png"/></svg:svg></span></span>
and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi>f</mi><mn mathvariant="normal">3</mn><mo>∗</mo></msubsup><msub><mi>f</mi><mtext>C</mtext></msub><msub><mi>f</mi><mtext>D</mtext></msub><mo>=</mo><mn mathvariant="normal">0.00337</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="83pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="9948fc960df7c711666d09b5b9e12773"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gchron-5-301-2023-ie00002.svg" width="83pt" height="14pt" src="gchron-5-301-2023-ie00002.png"/></svg:svg></span></span>).</p>
<p>Next, we demonstrate that the <span class="inline-formula"><sup>10</sup></span>Be–<span class="inline-formula"><sup>3</sup></span>He pair in pyroxene can be
used to simultaneously resolve erosion rates and exposure ages, finding that
the measured cosmogenic-nuclide concentrations in our surface samples are
best explained by 2–8 Myr of exposure at erosion rates of 0–35 cm Myr<span class="inline-formula"><sup>−1</sup></span>. Finally, given the low <span class="inline-formula"><sup>10</sup></span>Be in our laboratory blanks
(average of 5.7 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>3</sup></span> atoms), the reported measurement precision, and
our estimated production rate, it should be possible to measure 2 g samples
with <span class="inline-formula"><sup>10</sup></span>Be concentrations of 6 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>4</sup></span> and 1.5 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>4</sup></span> atoms g<span class="inline-formula"><sup>−1</sup></span> with 5 % and 15 % uncertainty, respectively. With
this level of precision, Last Glacial Maximum to Late Holocene surfaces can
now be dated with <span class="inline-formula"><sup>10</sup></span>Be in pyroxene. Application of <span class="inline-formula"><sup>10</sup></span>Be in
pyroxene, alone or in combination with <span class="inline-formula"><sup>3</sup></span>He, will expand possibilities
for investigating glacial histories and landscape change in mafic rock.</p> |
| first_indexed | 2024-04-24T22:27:36Z |
| format | Article |
| id | doaj.art-d5a14dc692d848da803f3acd24109377 |
| institution | Directory Open Access Journal |
| issn | 2628-3697 2628-3719 |
| language | English |
| last_indexed | 2024-04-24T22:27:36Z |
| publishDate | 2023-07-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geochronology |
| spelling | doaj.art-d5a14dc692d848da803f3acd241093772024-03-19T22:37:25ZengCopernicus PublicationsGeochronology2628-36972628-37192023-07-01530132110.5194/gchron-5-301-2023Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry ValleysA. Balter-Kennedy0A. Balter-Kennedy1J. M. Schaefer2J. M. Schaefer3R. Schwartz4J. L. Lamp5L. Penrose6J. Middleton7J. Hanley8B. Tibari9P.-H. Blard10G. Winckler11G. Winckler12A. J. Hidy13G. Balco14Lamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USADepartment of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USALamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USADepartment of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USALamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USALamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USALamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USALamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USALamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USACRPG, CNRS, Université de Lorraine, 54 000 Nancy, FranceCRPG, CNRS, Université de Lorraine, 54 000 Nancy, FranceLamont–Doherty Earth Observatory, Columbia University, Palisades, NY 10964, USADepartment of Earth and Environmental Sciences, Columbia University, New York, NY 10027, USADepartment is Center for Accelerator Mass Spectrometry, Lawrence Livermore National Laboratory, Livermore, CA 94550, USABerkeley Geochronology Center, Berkeley, CA 94709, USA<p>Here, we present cosmogenic-<span class="inline-formula"><sup>10</sup></span>Be and cosmogenic-<span class="inline-formula"><sup>3</sup></span>He data from Ferrar dolerite pyroxenes in surficial rock samples and a bedrock core from the McMurdo Dry Valleys, Antarctica, with the goal of refining the laboratory methods for extracting beryllium from pyroxene, further estimating the <span class="inline-formula"><sup>10</sup></span>Be production rate in pyroxene and demonstrating the applicability of <span class="inline-formula"><sup>10</sup></span>Be–<span class="inline-formula"><sup>3</sup></span>He in mafic rock. The ability to routinely measure cosmogenic <span class="inline-formula"><sup>10</sup></span>Be in pyroxene will open new opportunities for quantifying exposure durations and Earth surface processes in mafic rocks. We describe scalable laboratory methods for isolating beryllium from pyroxene, which include a simple hydrofluoric acid leaching procedure for removing meteoric <span class="inline-formula"><sup>10</sup></span>Be and the addition of a pH 8 precipitation step to reduce the cation load prior to ion exchange chromatography. <span class="inline-formula"><sup>10</sup></span>Be measurements in pyroxene from the surface samples have apparent <span class="inline-formula"><sup>3</sup></span>He exposure ages of 1–6 Myr. We estimate a spallation production rate for <span class="inline-formula"><sup>10</sup></span>Be in pyroxene, referenced to <span class="inline-formula"><sup>3</sup></span>He, of 3.6 <span class="inline-formula">±</span> 0.2 atoms g<span class="inline-formula"><sup>−1</sup></span> yr<span class="inline-formula"><sup>−1</sup></span>. <span class="inline-formula"><sup>10</sup></span>Be and <span class="inline-formula"><sup>3</sup></span>He measurements in the bedrock core yield initial estimates for parameters associated with <span class="inline-formula"><sup>10</sup></span>Be and <span class="inline-formula"><sup>3</sup></span>He production by negative-muon capture (<span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M23" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi>f</mi><mn mathvariant="normal">10</mn><mo>∗</mo></msubsup><mo>=</mo><mn mathvariant="normal">0.00183</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="67pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="b8d80758c5229555d2f87ecc0009ae48"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gchron-5-301-2023-ie00001.svg" width="67pt" height="14pt" src="gchron-5-301-2023-ie00001.png"/></svg:svg></span></span> and <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M24" display="inline" overflow="scroll" dspmath="mathml"><mrow><msubsup><mi>f</mi><mn mathvariant="normal">3</mn><mo>∗</mo></msubsup><msub><mi>f</mi><mtext>C</mtext></msub><msub><mi>f</mi><mtext>D</mtext></msub><mo>=</mo><mn mathvariant="normal">0.00337</mn></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="83pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="9948fc960df7c711666d09b5b9e12773"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="gchron-5-301-2023-ie00002.svg" width="83pt" height="14pt" src="gchron-5-301-2023-ie00002.png"/></svg:svg></span></span>).</p> <p>Next, we demonstrate that the <span class="inline-formula"><sup>10</sup></span>Be–<span class="inline-formula"><sup>3</sup></span>He pair in pyroxene can be used to simultaneously resolve erosion rates and exposure ages, finding that the measured cosmogenic-nuclide concentrations in our surface samples are best explained by 2–8 Myr of exposure at erosion rates of 0–35 cm Myr<span class="inline-formula"><sup>−1</sup></span>. Finally, given the low <span class="inline-formula"><sup>10</sup></span>Be in our laboratory blanks (average of 5.7 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>3</sup></span> atoms), the reported measurement precision, and our estimated production rate, it should be possible to measure 2 g samples with <span class="inline-formula"><sup>10</sup></span>Be concentrations of 6 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>4</sup></span> and 1.5 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>4</sup></span> atoms g<span class="inline-formula"><sup>−1</sup></span> with 5 % and 15 % uncertainty, respectively. With this level of precision, Last Glacial Maximum to Late Holocene surfaces can now be dated with <span class="inline-formula"><sup>10</sup></span>Be in pyroxene. Application of <span class="inline-formula"><sup>10</sup></span>Be in pyroxene, alone or in combination with <span class="inline-formula"><sup>3</sup></span>He, will expand possibilities for investigating glacial histories and landscape change in mafic rock.</p>https://gchron.copernicus.org/articles/5/301/2023/gchron-5-301-2023.pdf |
| spellingShingle | A. Balter-Kennedy A. Balter-Kennedy J. M. Schaefer J. M. Schaefer R. Schwartz J. L. Lamp L. Penrose J. Middleton J. Hanley B. Tibari P.-H. Blard G. Winckler G. Winckler A. J. Hidy G. Balco Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys Geochronology |
| title | Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys |
| title_full | Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys |
| title_fullStr | Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys |
| title_full_unstemmed | Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys |
| title_short | Cosmogenic <sup>10</sup>Be in pyroxene: laboratory progress, production rate systematics, and application of the <sup>10</sup>Be–<sup>3</sup>He nuclide pair in the Antarctic Dry Valleys |
| title_sort | cosmogenic sup 10 sup be in pyroxene laboratory progress production rate systematics and application of the sup 10 sup be sup 3 sup he nuclide pair in the antarctic dry valleys |
| url | https://gchron.copernicus.org/articles/5/301/2023/gchron-5-301-2023.pdf |
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