Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites?
International audience Apatite fission track thermochronology has been widely used to constrain the timing and rate of crustal exhumation at passive continental margins and cratonic settings by providing a record of rock cooling through c. 110 – 60 °C. Resolving more recent and smaller scale (c. <...
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ftunivrennes1hal:oai:HAL:insu-01734873v1 2024-05-19T07:40:09+00:00 Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? Wildman, Mark, M Gallagher, Kerry Gautheron, Cécile Géosciences Rennes (GR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) New Orleans, United States 2017-12-11 https://insu.hal.science/insu-01734873 en eng HAL CCSD insu-01734873 https://insu.hal.science/insu-01734873 American Geophysical Union Fall Meeting 2017 https://insu.hal.science/insu-01734873 American Geophysical Union Fall Meeting 2017, Dec 2017, New Orleans, United States. pp.T11D-06 [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/conferenceObject Conference papers 2017 ftunivrennes1hal 2024-05-02T00:02:35Z International audience Apatite fission track thermochronology has been widely used to constrain the timing and rate of crustal exhumation at passive continental margins and cratonic settings by providing a record of rock cooling through c. 110 – 60 °C. Resolving more recent and smaller scale (c. < 2 km) exhumation requires a thermochronometer with a lower temperature sensitivity. Apatite (U-Th-Sm)/He (AHe) thermochronology can potentially provide information that fills the gap in the thermal history of these settings. However, at such ancient and slowly cooled settings AHe datasets are commonly over-dispersed and their geological significance is difficult to interpret.A major source of AHe age dispersion is attributed to the effect of radiation damage within apatite, which acts to lower He diffusivity and increase the closure temperature of an apatite grain. It is appreciated that the role of radiation damage is particularly significant for apatite enriched in U and Th with slow or complex cooling histories over c. 100 million year timescales but while models of radiation damage accumulation and annealing have been able to explain many AHe datasets and extract useful thermal history information, many uncertainties in these models remain. New developments in our understanding of how He diffusion changes depending on damage shape, size, and connectivity and how composition affects defect annealing may be able to explain the most complex AHe datasets.Using data from African passive continental margins and cratonic settings in South Africa and Fennoscandia we evaluate the factors causing AHe age dispersion (i.e. radiation damage, grain size, fragmentation) and jointly invert the data alongside independent AFT data. By allowing the energy required for He atoms to escape damage defects (i.e. trapping energy) to vary we show that the AHe data can be well reproduced and important thermal history information can be obtained. Conference Object Fennoscandia Université de Rennes 1: Publications scientifiques (HAL) |
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Open Polar |
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Université de Rennes 1: Publications scientifiques (HAL) |
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ftunivrennes1hal |
language |
English |
topic |
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
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[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Wildman, Mark, M Gallagher, Kerry Gautheron, Cécile Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
topic_facet |
[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
International audience Apatite fission track thermochronology has been widely used to constrain the timing and rate of crustal exhumation at passive continental margins and cratonic settings by providing a record of rock cooling through c. 110 – 60 °C. Resolving more recent and smaller scale (c. < 2 km) exhumation requires a thermochronometer with a lower temperature sensitivity. Apatite (U-Th-Sm)/He (AHe) thermochronology can potentially provide information that fills the gap in the thermal history of these settings. However, at such ancient and slowly cooled settings AHe datasets are commonly over-dispersed and their geological significance is difficult to interpret.A major source of AHe age dispersion is attributed to the effect of radiation damage within apatite, which acts to lower He diffusivity and increase the closure temperature of an apatite grain. It is appreciated that the role of radiation damage is particularly significant for apatite enriched in U and Th with slow or complex cooling histories over c. 100 million year timescales but while models of radiation damage accumulation and annealing have been able to explain many AHe datasets and extract useful thermal history information, many uncertainties in these models remain. New developments in our understanding of how He diffusion changes depending on damage shape, size, and connectivity and how composition affects defect annealing may be able to explain the most complex AHe datasets.Using data from African passive continental margins and cratonic settings in South Africa and Fennoscandia we evaluate the factors causing AHe age dispersion (i.e. radiation damage, grain size, fragmentation) and jointly invert the data alongside independent AFT data. By allowing the energy required for He atoms to escape damage defects (i.e. trapping energy) to vary we show that the AHe data can be well reproduced and important thermal history information can be obtained. |
author2 |
Géosciences Rennes (GR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR) Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS) Géosciences Paris Sud (GEOPS) Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS) |
format |
Conference Object |
author |
Wildman, Mark, M Gallagher, Kerry Gautheron, Cécile |
author_facet |
Wildman, Mark, M Gallagher, Kerry Gautheron, Cécile |
author_sort |
Wildman, Mark, M |
title |
Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
title_short |
Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
title_full |
Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
title_fullStr |
Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
title_full_unstemmed |
Obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
title_sort |
obtaining thermal history information from old geological settings: how useful are radiation damaged apatites? |
publisher |
HAL CCSD |
publishDate |
2017 |
url |
https://insu.hal.science/insu-01734873 |
op_coverage |
New Orleans, United States |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_source |
American Geophysical Union Fall Meeting 2017 https://insu.hal.science/insu-01734873 American Geophysical Union Fall Meeting 2017, Dec 2017, New Orleans, United States. pp.T11D-06 |
op_relation |
insu-01734873 https://insu.hal.science/insu-01734873 |
_version_ |
1799479727739633664 |