Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas
The understanding of climatic mechanisms and rapid climate changes requires a high-resolution, robust, and precise timescale which allows long-distance and multi-archives correlations.An appropriate tool to construct such a timescale is provided by the Earth magnetic field (EMF). The EMF is independ...
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ftuniparissaclay:oai:HAL:tel-01266050v1 2024-06-16T07:40:43+00:00 Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas Développement d'un outil chronostratigraphique pour les archives climatiques : datations absolues (K/Ar,⁴⁰Ar/³⁹Ar) et paléomagnétisme appliqués aux laves Sasco, Romain Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Université Paris Sud - Paris XI Hervé Guillou 2015-01-28 https://theses.hal.science/tel-01266050 https://theses.hal.science/tel-01266050/document https://theses.hal.science/tel-01266050/file/VA2_SASCO_ROMAIN_28012015.pdf fr fre HAL CCSD NNT: 2015PA112009 tel-01266050 https://theses.hal.science/tel-01266050 https://theses.hal.science/tel-01266050/document https://theses.hal.science/tel-01266050/file/VA2_SASCO_ROMAIN_28012015.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01266050 Sciences de la Terre. Université Paris Sud - Paris XI, 2015. Français. ⟨NNT : 2015PA112009⟩ Earth magnetic field Paleomagnetism Paleointensity K-Ar dating ⁴⁰Ar/³⁹Ar dating Age-paleointensity data Timescale calibration Ardèche Canary Islands Champ magnétique terrestre Paléomagnétisme Paléointensité Datation K-Ar Datation ⁴⁰Ar/³⁹Ar Couple âge-paléointensité Calibration d’échelle de temps Îles Canaries [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2015 ftuniparissaclay 2024-05-17T00:14:23Z The understanding of climatic mechanisms and rapid climate changes requires a high-resolution, robust, and precise timescale which allows long-distance and multi-archives correlations.An appropriate tool to construct such a timescale is provided by the Earth magnetic field (EMF). The EMF is independent from climatic variations and its past evolution, global at the surface of the Earth, is recorded by most of the geological/climatic archives. Sedimentary sequences provide continuous records of relative intensities of the EMF on timescales usually based on ice core age models or orbital tuning. Lavas, though discontinuously emitted through time, record the absolute intensity of the EMF during their cooling at the surface of the Earth. Lavas are dated using 2 complementary methods: ⁴⁰Ar/³⁹Ar and K-Ar, both independent from climatic parameters. Lavas have therefore the potential to deliver tie-points (age-paleointensity couples) enabling the time calibration of sedimentary sequences and their transfer onto absolute intensity scale and chronological time scale. This timescale can then be transferred to other climatic archives. The present study focusses on the last 200 ka with lavas sampled from young volcanoes of Ardèche (South Massif Central, France) and recent phases of volcanism in the Canary Islands.Lava flows from Ardèche provided unexploitable paleointensity results and ages with large uncertainties. Therefore, they failed to provide suitable tie-points. However, our geochronological results evidence how crucial the combination of both the K-Ar and 40Ar/39Ar methods is to test the accuracy and geological meaning of the ages. Ardèche lavas have abundant mantellic and crustal xenoliths, potential carriers of excess ⁴⁰Ar*. Our study suggests that the argon excess is located in sites that decrepitate at low temperature (<600°C). Because ⁴⁰Ar/³⁹Ar ages are not affected by excess ⁴⁰Ar*, they provide reliable results. The new age dataset indicates that the volcanic activity of Ardèche can be divided in 3 phases: ... Doctoral or Postdoctoral Thesis ice core Archives ouvertes de Paris-Saclay |
institution |
Open Polar |
collection |
Archives ouvertes de Paris-Saclay |
op_collection_id |
ftuniparissaclay |
language |
French |
topic |
Earth magnetic field Paleomagnetism Paleointensity K-Ar dating ⁴⁰Ar/³⁹Ar dating Age-paleointensity data Timescale calibration Ardèche Canary Islands Champ magnétique terrestre Paléomagnétisme Paléointensité Datation K-Ar Datation ⁴⁰Ar/³⁹Ar Couple âge-paléointensité Calibration d’échelle de temps Îles Canaries [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Earth magnetic field Paleomagnetism Paleointensity K-Ar dating ⁴⁰Ar/³⁹Ar dating Age-paleointensity data Timescale calibration Ardèche Canary Islands Champ magnétique terrestre Paléomagnétisme Paléointensité Datation K-Ar Datation ⁴⁰Ar/³⁹Ar Couple âge-paléointensité Calibration d’échelle de temps Îles Canaries [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Sasco, Romain Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas |
topic_facet |
Earth magnetic field Paleomagnetism Paleointensity K-Ar dating ⁴⁰Ar/³⁹Ar dating Age-paleointensity data Timescale calibration Ardèche Canary Islands Champ magnétique terrestre Paléomagnétisme Paléointensité Datation K-Ar Datation ⁴⁰Ar/³⁹Ar Couple âge-paléointensité Calibration d’échelle de temps Îles Canaries [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
The understanding of climatic mechanisms and rapid climate changes requires a high-resolution, robust, and precise timescale which allows long-distance and multi-archives correlations.An appropriate tool to construct such a timescale is provided by the Earth magnetic field (EMF). The EMF is independent from climatic variations and its past evolution, global at the surface of the Earth, is recorded by most of the geological/climatic archives. Sedimentary sequences provide continuous records of relative intensities of the EMF on timescales usually based on ice core age models or orbital tuning. Lavas, though discontinuously emitted through time, record the absolute intensity of the EMF during their cooling at the surface of the Earth. Lavas are dated using 2 complementary methods: ⁴⁰Ar/³⁹Ar and K-Ar, both independent from climatic parameters. Lavas have therefore the potential to deliver tie-points (age-paleointensity couples) enabling the time calibration of sedimentary sequences and their transfer onto absolute intensity scale and chronological time scale. This timescale can then be transferred to other climatic archives. The present study focusses on the last 200 ka with lavas sampled from young volcanoes of Ardèche (South Massif Central, France) and recent phases of volcanism in the Canary Islands.Lava flows from Ardèche provided unexploitable paleointensity results and ages with large uncertainties. Therefore, they failed to provide suitable tie-points. However, our geochronological results evidence how crucial the combination of both the K-Ar and 40Ar/39Ar methods is to test the accuracy and geological meaning of the ages. Ardèche lavas have abundant mantellic and crustal xenoliths, potential carriers of excess ⁴⁰Ar*. Our study suggests that the argon excess is located in sites that decrepitate at low temperature (<600°C). Because ⁴⁰Ar/³⁹Ar ages are not affected by excess ⁴⁰Ar*, they provide reliable results. The new age dataset indicates that the volcanic activity of Ardèche can be divided in 3 phases: ... |
author2 |
Laboratoire des Sciences du Climat et de l'Environnement Gif-sur-Yvette (LSCE) Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)) Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA) Université Paris Sud - Paris XI Hervé Guillou |
format |
Doctoral or Postdoctoral Thesis |
author |
Sasco, Romain |
author_facet |
Sasco, Romain |
author_sort |
Sasco, Romain |
title |
Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas |
title_short |
Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas |
title_full |
Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas |
title_fullStr |
Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas |
title_full_unstemmed |
Developing a chronostratigraphic tool for climatic archives : absolute dating (K/Ar and ⁴⁰Ar/³⁹Ar) and paleomagnetism applied to lavas |
title_sort |
developing a chronostratigraphic tool for climatic archives : absolute dating (k/ar and ⁴⁰ar/³⁹ar) and paleomagnetism applied to lavas |
publisher |
HAL CCSD |
publishDate |
2015 |
url |
https://theses.hal.science/tel-01266050 https://theses.hal.science/tel-01266050/document https://theses.hal.science/tel-01266050/file/VA2_SASCO_ROMAIN_28012015.pdf |
genre |
ice core |
genre_facet |
ice core |
op_source |
https://theses.hal.science/tel-01266050 Sciences de la Terre. Université Paris Sud - Paris XI, 2015. Français. ⟨NNT : 2015PA112009⟩ |
op_relation |
NNT: 2015PA112009 tel-01266050 https://theses.hal.science/tel-01266050 https://theses.hal.science/tel-01266050/document https://theses.hal.science/tel-01266050/file/VA2_SASCO_ROMAIN_28012015.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1802007702672506880 |