Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time
The composition and the evolution of the silicate Earth during the Hadean-Eoarchean is widely debated and largely unknown due to the limited geological record. The first undisputable evidence for a very early differentiation of the mantle came from the extinct 146Sm-142Nd chronometer. The 142Nd exce...
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Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
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Online Access: | https://theses.hal.science/tel-00861891 https://theses.hal.science/tel-00861891/document https://theses.hal.science/tel-00861891/file/Rizo-2012CLF22270.pdf |
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ftclermontuniv:oai:HAL:tel-00861891v1 2024-09-15T18:09:48+00:00 Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time Différenciation précoce de la terre silicatée enregistrée dans les roches archéennes d'Isua (Groenland) : implications sur la dynamique du manteau au cours du temps Rizo Garza, Hanika Laboratoire Magmas et Volcans (LMV) Observatoire de Physique du Globe de Clermont-Ferrand (OPGC) Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) Université Blaise Pascal - Clermont-Ferrand II Maud Boyet Hervé Martin 2012-09-27 https://theses.hal.science/tel-00861891 https://theses.hal.science/tel-00861891/document https://theses.hal.science/tel-00861891/file/Rizo-2012CLF22270.pdf fr fre HAL CCSD NNT: 2012CLF22270 tel-00861891 https://theses.hal.science/tel-00861891 https://theses.hal.science/tel-00861891/document https://theses.hal.science/tel-00861891/file/Rizo-2012CLF22270.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-00861891 Sciences de la Terre. Université Blaise Pascal - Clermont-Ferrand II, 2012. Français. ⟨NNT : 2012CLF22270⟩ Archean Isua Silicate Earth Early differentiation 142Nd Hadean Archeen Hadéen Terre silicatée Différenciation précoce [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/doctoralThesis Theses 2012 ftclermontuniv 2024-09-03T05:22:44Z The composition and the evolution of the silicate Earth during the Hadean-Eoarchean is widely debated and largely unknown due to the limited geological record. The first undisputable evidence for a very early differentiation of the mantle came from the extinct 146Sm-142Nd chronometer. The 142Nd excesses measured in 3.7 billion year (Ga) old rocks from Isua (Southwest Greenland) relative to modern terrestrial samples imply their derivation from a depleted mantle formed in the Hadean. We have studied 146,147Sm–142,143Nd and 176Lu–176Hf isotope systematics in 3.8 Ga, 3.7 Ga, 3.4 Ga and 3.3 Ga mantle-derived samples from different tectonic domains of the Isua region. This dataset covers ~ 500 million years of the early history of the Earth and revealed precious information about the compositional evolution and dynamics of the early Earth mantle. Combined Lu-Hf and Sm-Nd of the 3.7 Ga Isua samples revealed that these isotopic systematics were decoupled, suggesting a deep-seated source for the Isua lavas. We have further expanded the dataset and confirmed the 142Nd excesses in these rocks, implying that their source was depleted and differentiated during the first 100 Ma of Earth’s history. The differentiation event that created this early-depleted reservoir had to also form a complementary enriched component. We have found the first evidence for this reservoir recorded in the 3.4 Ga samples that yielded negative 142Nd anomalies. However, the 3.3 Ga analyzed samples showed no resolvable 142Nd anomalies compared to terrestrial Nd standards. This suggests that the Hadean heterogeneities were likely isolated for more than 1 Ga before being completely rehomogeneized by 3.3 Ga. The remixing by 3.3 Ga could have been achieved by subduction processes due to the onset of modern plate tectonics at ~3.2 Ga, as proposed by other recent studies. L’enregistrement géologique de l’Hadéen et de l’Eoarcheén étant limité, la composition et l’évolution de la Terre silicatée au cours de ces périodes reste très débattue et peu connue. ... Doctoral or Postdoctoral Thesis Greenland Groenland HAL Clermont Auvergne (Université Blaise Pascal Clermont-Ferrand/Université d'Auvergne) |
institution |
Open Polar |
collection |
HAL Clermont Auvergne (Université Blaise Pascal Clermont-Ferrand/Université d'Auvergne) |
op_collection_id |
ftclermontuniv |
language |
French |
topic |
Archean Isua Silicate Earth Early differentiation 142Nd Hadean Archeen Hadéen Terre silicatée Différenciation précoce [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
Archean Isua Silicate Earth Early differentiation 142Nd Hadean Archeen Hadéen Terre silicatée Différenciation précoce [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Rizo Garza, Hanika Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time |
topic_facet |
Archean Isua Silicate Earth Early differentiation 142Nd Hadean Archeen Hadéen Terre silicatée Différenciation précoce [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
The composition and the evolution of the silicate Earth during the Hadean-Eoarchean is widely debated and largely unknown due to the limited geological record. The first undisputable evidence for a very early differentiation of the mantle came from the extinct 146Sm-142Nd chronometer. The 142Nd excesses measured in 3.7 billion year (Ga) old rocks from Isua (Southwest Greenland) relative to modern terrestrial samples imply their derivation from a depleted mantle formed in the Hadean. We have studied 146,147Sm–142,143Nd and 176Lu–176Hf isotope systematics in 3.8 Ga, 3.7 Ga, 3.4 Ga and 3.3 Ga mantle-derived samples from different tectonic domains of the Isua region. This dataset covers ~ 500 million years of the early history of the Earth and revealed precious information about the compositional evolution and dynamics of the early Earth mantle. Combined Lu-Hf and Sm-Nd of the 3.7 Ga Isua samples revealed that these isotopic systematics were decoupled, suggesting a deep-seated source for the Isua lavas. We have further expanded the dataset and confirmed the 142Nd excesses in these rocks, implying that their source was depleted and differentiated during the first 100 Ma of Earth’s history. The differentiation event that created this early-depleted reservoir had to also form a complementary enriched component. We have found the first evidence for this reservoir recorded in the 3.4 Ga samples that yielded negative 142Nd anomalies. However, the 3.3 Ga analyzed samples showed no resolvable 142Nd anomalies compared to terrestrial Nd standards. This suggests that the Hadean heterogeneities were likely isolated for more than 1 Ga before being completely rehomogeneized by 3.3 Ga. The remixing by 3.3 Ga could have been achieved by subduction processes due to the onset of modern plate tectonics at ~3.2 Ga, as proposed by other recent studies. L’enregistrement géologique de l’Hadéen et de l’Eoarcheén étant limité, la composition et l’évolution de la Terre silicatée au cours de ces périodes reste très débattue et peu connue. ... |
author2 |
Laboratoire Magmas et Volcans (LMV) Observatoire de Physique du Globe de Clermont-Ferrand (OPGC) Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS) Université Blaise Pascal - Clermont-Ferrand II Maud Boyet Hervé Martin |
format |
Doctoral or Postdoctoral Thesis |
author |
Rizo Garza, Hanika |
author_facet |
Rizo Garza, Hanika |
author_sort |
Rizo Garza, Hanika |
title |
Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time |
title_short |
Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time |
title_full |
Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time |
title_fullStr |
Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time |
title_full_unstemmed |
Early differentiation of silicate soil recorded in Archean rocks of Isua (Greenland) : implications on mantle dynamics over time |
title_sort |
early differentiation of silicate soil recorded in archean rocks of isua (greenland) : implications on mantle dynamics over time |
publisher |
HAL CCSD |
publishDate |
2012 |
url |
https://theses.hal.science/tel-00861891 https://theses.hal.science/tel-00861891/document https://theses.hal.science/tel-00861891/file/Rizo-2012CLF22270.pdf |
genre |
Greenland Groenland |
genre_facet |
Greenland Groenland |
op_source |
https://theses.hal.science/tel-00861891 Sciences de la Terre. Université Blaise Pascal - Clermont-Ferrand II, 2012. Français. ⟨NNT : 2012CLF22270⟩ |
op_relation |
NNT: 2012CLF22270 tel-00861891 https://theses.hal.science/tel-00861891 https://theses.hal.science/tel-00861891/document https://theses.hal.science/tel-00861891/file/Rizo-2012CLF22270.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1810447397872992256 |