Glacial erosion and history of Inglefield Land, northwestern Greenland
<p>We used mapping of bedrock lithology, bedrock fractures, and lake density in Inglefield Land, northwestern Greenland, combined with cosmogenic nuclide (<span class="inline-formula"><sup>10</sup></span>Be and <span class="inline-formula"><...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2025-06-01
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| Series: | The Cryosphere |
| Online Access: | https://tc.copernicus.org/articles/19/2067/2025/tc-19-2067-2025.pdf |
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| Summary: | <p>We used mapping of bedrock lithology, bedrock fractures, and lake density in Inglefield Land, northwestern Greenland, combined with cosmogenic nuclide (<span class="inline-formula"><sup>10</sup></span>Be and <span class="inline-formula"><sup>26</sup></span>Al) measurements in bedrock surfaces, to investigate glacial erosion and the ice sheet history of the northwestern Greenland Ice Sheet. The pattern of eroded versus weathered bedrock surfaces and other glacial erosion indicators reveal temporally and spatially varying erosion under cold- and warm-based ice. All of the bedrock surfaces that we measured in Inglefield Land contain cosmogenic nuclide inheritance with apparent <span class="inline-formula"><sup>10</sup></span>Be ages ranging from 24.9 <span class="inline-formula">±</span> 0.5 to 215.8 <span class="inline-formula">±</span> 7.4 ka. The <span class="inline-formula"><math xmlns="http://www.w3.org/1998/Math/MathML" id="M6" display="inline" overflow="scroll" dspmath="mathml"><mrow class="chem"><msup><mi/><mn mathvariant="normal">26</mn></msup><mi mathvariant="normal">Al</mi><msup><mo>/</mo><mn mathvariant="normal">10</mn></msup><mi mathvariant="normal">Be</mi></mrow></math><span><svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="50pt" height="15pt" class="svg-formula" dspmath="mathimg" md5hash="413c8bc7c901e512d748d90bf62188b6"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="tc-19-2067-2025-ie00001.svg" width="50pt" height="15pt" src="tc-19-2067-2025-ie00001.png"/></svg:svg></span></span> ratios require minimum combined surface burial and exposure histories of <span class="inline-formula">∼</span> 150 to 2000 kyr. Because our sample sites span a relatively small area that experienced a similar ice sheet history, we attribute differences in nuclide concentrations and ratios to varying erosion during the Quaternary. We show that an ice sheet history with <span class="inline-formula">∼</span> 900 kyr of exposure and <span class="inline-formula">∼</span> 1800 kyr of ice cover throughout the Quaternary is consistent with the measured nuclide concentrations in most samples when sample-specific subaerial erosion rates are between 0 and 2 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>−2</sup></span> mm yr<span class="inline-formula"><sup>−1</sup></span> and subglacial erosion rates are between 0 and 2 <span class="inline-formula">×</span> 10<span class="inline-formula"><sup>−3</sup></span> mm yr<span class="inline-formula"><sup>−1</sup></span>. These erosion rates help to characterize Arctic landscape evolution in crystalline bedrock terrains in areas away from focused ice flow.</p> |
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| ISSN: | 1994-0416 1994-0424 |