Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath
<p>An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes where glacial–interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene. The Last Glacial Maximum (LGM) was reached...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2024-04-01
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| Series: | Solid Earth |
| Online Access: | https://se.copernicus.org/articles/15/387/2024/se-15-387-2024.pdf |
| _version_ | 1797226093580648448 |
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| author | V. A. P. Muller V. A. P. Muller P. Sternai C. Sue C. Sue |
| author_facet | V. A. P. Muller V. A. P. Muller P. Sternai C. Sue C. Sue |
| author_sort | V. A. P. Muller |
| collection | DOAJ |
| description | <p>An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes where glacial–interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene. The Last Glacial Maximum (LGM) was reached <span class="inline-formula">∼26 000</span> yr BP (years before present). Significant deglaciation onsets between 21 000 and 17 000 yr BP were subject to an acceleration since the Little Ice Age (LIA), which was <span class="inline-formula">∼400</span> yr BP. Fast uplift rates of up to <span class="inline-formula">41±3</span> mm yr<span class="inline-formula"><sup>−1</sup></span> are measured by global navigation satellite system (GNSS) around the Southern Patagonian Icefield and are currently ascribed to post-LIA lithospheric rebound, but the possible longer-term post-LGM rebound is poorly constrained. These uplift rates, in addition, are 1 order of magnitude higher than those measured on other glaciated orogens (e.g. the European Alps), which raises questions about the role of the asthenospheric window in affecting the vertical surface displacement rates. Here, we perform geodynamic thermo-mechanical numerical modelling to estimate the surface uplift rates induced by post-LIA and post-LGM deglaciation, accounting for temperature-dependent rheologies and different thermal regimes in the asthenosphere. Our modelled maximum post-glacial rebound matches the observed uplift rate budget only when both post-LIA and post-LGM deglaciation are accounted for and only if a standard continental asthenospheric mantle potential temperature is increased by 150–200 °C. The asthenospheric window thus plays a key role in controlling the magnitude of presently observed uplift rates in the southern Patagonian Andes.</p> |
| first_indexed | 2024-04-24T14:19:26Z |
| format | Article |
| id | doaj.art-762da18d5ff94a898bba3c25722352cf |
| institution | Directory Open Access Journal |
| issn | 1869-9510 1869-9529 |
| language | English |
| last_indexed | 2024-04-24T14:19:26Z |
| publishDate | 2024-04-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Solid Earth |
| spelling | doaj.art-762da18d5ff94a898bba3c25722352cf2024-04-03T07:29:07ZengCopernicus PublicationsSolid Earth1869-95101869-95292024-04-011538740410.5194/se-15-387-2024Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneathV. A. P. Muller0V. A. P. Muller1P. Sternai2C. Sue3C. Sue4Dipartimento di Scienze dell'Ambiente e della Terra (DISAT), Università degli Studi di Milano-Bicocca, Piazza della Scienza 4, Milan, Italycurrently at: Department of Geosciences, University of Arizona, Tucson, USADipartimento di Scienze dell'Ambiente e della Terra (DISAT), Università degli Studi di Milano-Bicocca, Piazza della Scienza 4, Milan, ItalyInstitute des Sciences de la Terre (ISTerre), Université Grenoble Alpes, Université Savoie Mont Blanc, CNRS, IRD, IFSTTAR, Université Gustave Eiffel, Grenoble, France Geology Department, Université de Franche-Comté, Besançon, France<p>An asthenospheric window underneath much of the South American continent increases the heat flow in the southern Patagonian Andes where glacial–interglacial cycles drive the building and melting of the Patagonian Icefields since the latest Miocene. The Last Glacial Maximum (LGM) was reached <span class="inline-formula">∼26 000</span> yr BP (years before present). Significant deglaciation onsets between 21 000 and 17 000 yr BP were subject to an acceleration since the Little Ice Age (LIA), which was <span class="inline-formula">∼400</span> yr BP. Fast uplift rates of up to <span class="inline-formula">41±3</span> mm yr<span class="inline-formula"><sup>−1</sup></span> are measured by global navigation satellite system (GNSS) around the Southern Patagonian Icefield and are currently ascribed to post-LIA lithospheric rebound, but the possible longer-term post-LGM rebound is poorly constrained. These uplift rates, in addition, are 1 order of magnitude higher than those measured on other glaciated orogens (e.g. the European Alps), which raises questions about the role of the asthenospheric window in affecting the vertical surface displacement rates. Here, we perform geodynamic thermo-mechanical numerical modelling to estimate the surface uplift rates induced by post-LIA and post-LGM deglaciation, accounting for temperature-dependent rheologies and different thermal regimes in the asthenosphere. Our modelled maximum post-glacial rebound matches the observed uplift rate budget only when both post-LIA and post-LGM deglaciation are accounted for and only if a standard continental asthenospheric mantle potential temperature is increased by 150–200 °C. The asthenospheric window thus plays a key role in controlling the magnitude of presently observed uplift rates in the southern Patagonian Andes.</p>https://se.copernicus.org/articles/15/387/2024/se-15-387-2024.pdf |
| spellingShingle | V. A. P. Muller V. A. P. Muller P. Sternai C. Sue C. Sue Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath Solid Earth |
| title | Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath |
| title_full | Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath |
| title_fullStr | Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath |
| title_full_unstemmed | Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath |
| title_short | Fast uplift in the southern Patagonian Andes due to long- and short-term deglaciation and the asthenospheric window underneath |
| title_sort | fast uplift in the southern patagonian andes due to long and short term deglaciation and the asthenospheric window underneath |
| url | https://se.copernicus.org/articles/15/387/2024/se-15-387-2024.pdf |
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