Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives
International audience The chemical weathering of rocks with sulfuric acid is usually not considered in reconstructions of the past evolution of the carbon cycle, although this reaction delivers cations and alkalinity to the ocean without involvement of atmospheric CO2. The contribution of sulfuric...
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ftunivparis:oai:HAL:hal-00310625v1 2023-10-09T21:53:25+02:00 Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives Calmels, Damien Gaillardet, Jérôme Brenot, Agnès France-Lanord, Christian Institut de Physique du Globe de Paris (IPGP) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS) Centre de Recherches Pétrographiques et Géochimiques (CRPG) Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS) 2007 https://hal.science/hal-00310625 https://doi.org/10.1130/G24132A.1 en eng HAL CCSD Geological Society of America info:eu-repo/semantics/altIdentifier/doi/10.1130/G24132A.1 hal-00310625 https://hal.science/hal-00310625 doi:10.1130/G24132A.1 ISSN: 0091-7613 EISSN: 1943-2682 Geology https://hal.science/hal-00310625 Geology, 2007, 35, pp.1003-1006. ⟨10.1130/G24132A.1⟩ carbonate weathering sulfide oxidation mechanical erosion Mackenzie River atmospheric CO2 [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry info:eu-repo/semantics/article Journal articles 2007 ftunivparis https://doi.org/10.1130/G24132A.1 2023-09-13T16:21:00Z International audience The chemical weathering of rocks with sulfuric acid is usually not considered in reconstructions of the past evolution of the carbon cycle, although this reaction delivers cations and alkalinity to the ocean without involvement of atmospheric CO2. The contribution of sulfuric acid as a weathering agent is still poorly quantified; the identification of riverine sulfate sources is difficult. The use of δ34S and δ18O of dissolved sulfate allows us to demonstrate that most of the sulfate in surface waters of the Mackenzie River system, Canada, derives from pyrite oxidation (85% ± 5%) and not from sedimentary sulfate. The calculated flux of pyrite-derived sulfate is 0.13 × 1012 mol/yr, corresponding to 20%–27% of the estimated global budget. This result suggests that the modern global ocean delivery of sulfide-derived sulfate, and thus chemical weathering with sulfuric acid, may be significantly underestimated. A strong correlation between sulfide oxidation rates and mechanical erosion rates suggests that the exposure of fresh mineral surfaces is the rate-limiting factor of sulfide oxidation in the subbasins investigated. The chemical weathering budget of the Mackenzie River shows that more than half of the dissolved inorganic carbon discharged to the ocean is ancient sedimentary carbon from carbonate (62%) and not atmospheric carbon (38%). The subsequent carbonate precipitation in the ocean will thus release more CO2 in the atmosphere-ocean system than that consumed by continental weathering, typically on glacial-interglacial time scales. Article in Journal/Newspaper Mackenzie river Université de Paris: Portail HAL Canada Mackenzie River Geology 35 11 1003 |
institution |
Open Polar |
collection |
Université de Paris: Portail HAL |
op_collection_id |
ftunivparis |
language |
English |
topic |
carbonate weathering sulfide oxidation mechanical erosion Mackenzie River atmospheric CO2 [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
spellingShingle |
carbonate weathering sulfide oxidation mechanical erosion Mackenzie River atmospheric CO2 [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry Calmels, Damien Gaillardet, Jérôme Brenot, Agnès France-Lanord, Christian Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives |
topic_facet |
carbonate weathering sulfide oxidation mechanical erosion Mackenzie River atmospheric CO2 [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry |
description |
International audience The chemical weathering of rocks with sulfuric acid is usually not considered in reconstructions of the past evolution of the carbon cycle, although this reaction delivers cations and alkalinity to the ocean without involvement of atmospheric CO2. The contribution of sulfuric acid as a weathering agent is still poorly quantified; the identification of riverine sulfate sources is difficult. The use of δ34S and δ18O of dissolved sulfate allows us to demonstrate that most of the sulfate in surface waters of the Mackenzie River system, Canada, derives from pyrite oxidation (85% ± 5%) and not from sedimentary sulfate. The calculated flux of pyrite-derived sulfate is 0.13 × 1012 mol/yr, corresponding to 20%–27% of the estimated global budget. This result suggests that the modern global ocean delivery of sulfide-derived sulfate, and thus chemical weathering with sulfuric acid, may be significantly underestimated. A strong correlation between sulfide oxidation rates and mechanical erosion rates suggests that the exposure of fresh mineral surfaces is the rate-limiting factor of sulfide oxidation in the subbasins investigated. The chemical weathering budget of the Mackenzie River shows that more than half of the dissolved inorganic carbon discharged to the ocean is ancient sedimentary carbon from carbonate (62%) and not atmospheric carbon (38%). The subsequent carbonate precipitation in the ocean will thus release more CO2 in the atmosphere-ocean system than that consumed by continental weathering, typically on glacial-interglacial time scales. |
author2 |
Institut de Physique du Globe de Paris (IPGP) Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS) Centre de Recherches Pétrographiques et Géochimiques (CRPG) Institut national des sciences de l'Univers (INSU - CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS) |
format |
Article in Journal/Newspaper |
author |
Calmels, Damien Gaillardet, Jérôme Brenot, Agnès France-Lanord, Christian |
author_facet |
Calmels, Damien Gaillardet, Jérôme Brenot, Agnès France-Lanord, Christian |
author_sort |
Calmels, Damien |
title |
Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives |
title_short |
Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives |
title_full |
Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives |
title_fullStr |
Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives |
title_full_unstemmed |
Sustained sulfide oxidation by physical erosion processes in the Mackenzie River basin: Climatic perspectives |
title_sort |
sustained sulfide oxidation by physical erosion processes in the mackenzie river basin: climatic perspectives |
publisher |
HAL CCSD |
publishDate |
2007 |
url |
https://hal.science/hal-00310625 https://doi.org/10.1130/G24132A.1 |
geographic |
Canada Mackenzie River |
geographic_facet |
Canada Mackenzie River |
genre |
Mackenzie river |
genre_facet |
Mackenzie river |
op_source |
ISSN: 0091-7613 EISSN: 1943-2682 Geology https://hal.science/hal-00310625 Geology, 2007, 35, pp.1003-1006. ⟨10.1130/G24132A.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1130/G24132A.1 hal-00310625 https://hal.science/hal-00310625 doi:10.1130/G24132A.1 |
op_doi |
https://doi.org/10.1130/G24132A.1 |
container_title |
Geology |
container_volume |
35 |
container_issue |
11 |
container_start_page |
1003 |
_version_ |
1779316676825710592 |