Multiple ice flow modelling to locate an old-ice coring site
Antarctic ice is an exceptional archive of ancient atmospheric air. The oldest available ice archive (800 ka) is not old enough to study a main climatic transition that occurred between 1.2 Ma and 0.9 Ma (mid-Pleistocene transition). Locating a future old-ice drill site is now one of the main goal o...
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ftunivnantes:oai:HAL:tel-01690458v2 2023-05-15T13:49:12+02:00 Multiple ice flow modelling to locate an old-ice coring site Localiser une archive glaciaire de 1.5 millions d'années par une approche multi-modèles Passalacqua, Olivier Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Université Grenoble Alpes Frédéric Parrenin Olivier Gagliardini 2017-10-13 https://theses.hal.science/tel-01690458 https://theses.hal.science/tel-01690458v2/document https://theses.hal.science/tel-01690458v2/file/PASSALACQUA_2017_diffusion.pdf fr fre HAL CCSD NNT: 2017GREAU024 tel-01690458 https://theses.hal.science/tel-01690458 https://theses.hal.science/tel-01690458v2/document https://theses.hal.science/tel-01690458v2/file/PASSALACQUA_2017_diffusion.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01690458 Glaciologie. Université Grenoble Alpes, 2017. Français. ⟨NNT : 2017GREAU024⟩ Modelling Glaciology Finite elements Dating Inversion Elmer/Ice Modélisation Glaciologie Éléments finis Datation [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology info:eu-repo/semantics/doctoralThesis Theses 2017 ftunivnantes 2023-03-08T06:27:54Z Antarctic ice is an exceptional archive of ancient atmospheric air. The oldest available ice archive (800 ka) is not old enough to study a main climatic transition that occurred between 1.2 Ma and 0.9 Ma (mid-Pleistocene transition). Locating a future old-ice drill site is now one of the main goal of the ice-core community. In the region of Dome C, several old-ice targets have required characteristics, from a thermal and mechanical point of view, to hosts very old ice. The goal of this work is to precisely locate suitable coring sites, using several glaciological models. First a 1D heat model to compute the local geothermal flux, that make us confident in the fact that bedrock heights have been free of basal melting for at least the last 800 ka. It is very likely that such sites are able to host a 1.5 Ma ice archive. Second, a 3D ice flow model, to describe the ice trajectories from the ice surface to the bed. Drilling less than 10 km from the surface ridge mimimizes the risks of stratigraphic disturbance, and drilling on the flanks of the bed relief - and not on its top - is mandatory to ensure a sufficient age resolution. Third, a 1D dating model constrained by isochrones let us describe the distribution of basal ages and age resolutions compatible with observed isochrones, and assess the risk of success or failure of the drilling. With currently available data and modelling tools, two drilling sites are proposed that are located 37 km from Dome C, at which 1.5 Ma-old ice is very likely to be archived in required conditions and with sufficient resolution. Les glaces de l'Antarctique constituent un matériau d'archivage unique pour garder la trace de l'atmosphère du passé. La plus ancienne archive glaciaire disponible (800 ka) ne permet malheureusement pas d'étudier une transition climatique majeure qui s'est déroulé entre 1.2 Ma et 0.9 Ma (transition du mi-Pleistocène). Localiser un site ayant permis la conservation d'une glace aussi ancienne est donc un enjeu majeur au sein de la communauté des carottes de ... Doctoral or Postdoctoral Thesis Antarc* Antarctic ice core Université de Nantes: HAL-UNIV-NANTES Antarctic |
institution |
Open Polar |
collection |
Université de Nantes: HAL-UNIV-NANTES |
op_collection_id |
ftunivnantes |
language |
French |
topic |
Modelling Glaciology Finite elements Dating Inversion Elmer/Ice Modélisation Glaciologie Éléments finis Datation [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology |
spellingShingle |
Modelling Glaciology Finite elements Dating Inversion Elmer/Ice Modélisation Glaciologie Éléments finis Datation [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology Passalacqua, Olivier Multiple ice flow modelling to locate an old-ice coring site |
topic_facet |
Modelling Glaciology Finite elements Dating Inversion Elmer/Ice Modélisation Glaciologie Éléments finis Datation [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology |
description |
Antarctic ice is an exceptional archive of ancient atmospheric air. The oldest available ice archive (800 ka) is not old enough to study a main climatic transition that occurred between 1.2 Ma and 0.9 Ma (mid-Pleistocene transition). Locating a future old-ice drill site is now one of the main goal of the ice-core community. In the region of Dome C, several old-ice targets have required characteristics, from a thermal and mechanical point of view, to hosts very old ice. The goal of this work is to precisely locate suitable coring sites, using several glaciological models. First a 1D heat model to compute the local geothermal flux, that make us confident in the fact that bedrock heights have been free of basal melting for at least the last 800 ka. It is very likely that such sites are able to host a 1.5 Ma ice archive. Second, a 3D ice flow model, to describe the ice trajectories from the ice surface to the bed. Drilling less than 10 km from the surface ridge mimimizes the risks of stratigraphic disturbance, and drilling on the flanks of the bed relief - and not on its top - is mandatory to ensure a sufficient age resolution. Third, a 1D dating model constrained by isochrones let us describe the distribution of basal ages and age resolutions compatible with observed isochrones, and assess the risk of success or failure of the drilling. With currently available data and modelling tools, two drilling sites are proposed that are located 37 km from Dome C, at which 1.5 Ma-old ice is very likely to be archived in required conditions and with sufficient resolution. Les glaces de l'Antarctique constituent un matériau d'archivage unique pour garder la trace de l'atmosphère du passé. La plus ancienne archive glaciaire disponible (800 ka) ne permet malheureusement pas d'étudier une transition climatique majeure qui s'est déroulé entre 1.2 Ma et 0.9 Ma (transition du mi-Pleistocène). Localiser un site ayant permis la conservation d'une glace aussi ancienne est donc un enjeu majeur au sein de la communauté des carottes de ... |
author2 |
Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes 2016-2019 (UGA 2016-2019 ) Université Grenoble Alpes Frédéric Parrenin Olivier Gagliardini |
format |
Doctoral or Postdoctoral Thesis |
author |
Passalacqua, Olivier |
author_facet |
Passalacqua, Olivier |
author_sort |
Passalacqua, Olivier |
title |
Multiple ice flow modelling to locate an old-ice coring site |
title_short |
Multiple ice flow modelling to locate an old-ice coring site |
title_full |
Multiple ice flow modelling to locate an old-ice coring site |
title_fullStr |
Multiple ice flow modelling to locate an old-ice coring site |
title_full_unstemmed |
Multiple ice flow modelling to locate an old-ice coring site |
title_sort |
multiple ice flow modelling to locate an old-ice coring site |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://theses.hal.science/tel-01690458 https://theses.hal.science/tel-01690458v2/document https://theses.hal.science/tel-01690458v2/file/PASSALACQUA_2017_diffusion.pdf |
geographic |
Antarctic |
geographic_facet |
Antarctic |
genre |
Antarc* Antarctic ice core |
genre_facet |
Antarc* Antarctic ice core |
op_source |
https://theses.hal.science/tel-01690458 Glaciologie. Université Grenoble Alpes, 2017. Français. ⟨NNT : 2017GREAU024⟩ |
op_relation |
NNT: 2017GREAU024 tel-01690458 https://theses.hal.science/tel-01690458 https://theses.hal.science/tel-01690458v2/document https://theses.hal.science/tel-01690458v2/file/PASSALACQUA_2017_diffusion.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1766251000553799680 |