| Titre | Characteristics of Hg concentrations and isotopes in terrestrial and marine facies across the end-Permian mass extinction |
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| Auteur | Wang, X; Cawood, P A; Grasby, S E ; Zhao, L; Chen, Z -Q; Wu, S; Yuangeng, H |
| Source | Global and Planetary Change vol. 205, 103592, 2021 p. 1-16, https://doi.org/10.1016/j.gloplacha.2021.103592 |
| Image |  |
| Année | 2021 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20210501 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.gloplacha.2021.103592 |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Colombie-Britannique; Yukon |
| SNRC | 75; 85; 95; 105; 115; 76; 86; 96; 106; 116; 77; 87; 97; 107; 117 |
| Lat/Long OENS | -145.0000 -105.0000 72.0000 60.0000 |
| Sujets | températures au sol; vitesse des ondes sismiques; mouvements de la croûte; études de la croûte; manteau terrestre; Eocene; Cordillère canadienne; Faille de Tintina ; Zone de faille de Tintina ; Sciences
et technologie; géologie structurale; géologie des dépôts meubles/géomorphologie; tectonique; Cénozoïque |
| Illustrations | cartes de localisation; profils; graphiques; figures |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Terrane Pearya, Ellesmere nord de l'ouest de l'Arctique |
| Diffusé | 2021 07 30 |
| Résumé | (disponible en anglais seulement)
The end Permian mass extinction (EPME) is the greatest among the "Big Five" extinctions of the Phanerozoic, and is believed to have been triggered primarily by
the Siberian Traps Large Igneous Province (STLIP). This hypothesis is supported by the temporal correlation of STLIP with the EPME by radiometric ages and Hg enrichments in sedimentary rocks. However, how signatures of volcanic Hg emissions are
preserved in sediments, and how this may vary from deep basin to shelf to terrestrial successions, remain unclear. To examine variability in the Hg record in different environments, we systematically measured organic carbon isotopes, Hg
concentrations and isotopes, major elements, and total organic carbon (TOC) contents from: 1) a terrestrial section at Chahe, 2) a marine-nonmarine transitional section at Jinzhong both in Guizhou Province, Southwest China. Results show that Hg
versus TOC and Hg versus Al exhibit no correlation through the terrestrial section at Chahe, whereas there is positive correlation in the transitional Jinzhong section. These relationships indicate that organic matter and clay minerals would not
affect Hg fluctuations on land, but dominates Hg sequestration in transitional settings. Thus, Hg/TOC along with Hg/Al ratios were able to be employed to recognize abnormal Hg deposition in Jinzhong, and Hg concentrations were utilized to examine
records of Hg enrichments in Chahe. The studied sections all show synchronous changes between carbon isotopic perturbations and Hg deposition events with first Hg enrichment and associated negative carbon isotopic negative excursion coinciding with
terrestrial ecological disturbance and with a second Hg enrichment corresponding to the largest carbon isotopic negative excursion and marine biological crisis. These trends across the Permian-Triassic boundary are also observed in other 13 sections
around the world, indicating a common source that injected massive CO2 and Hg, impacting the global C and Hg cycles. Hg isotope (d199Hg values) of the first peak in Hg concentrations have similar characteristics in the terrestrial Chahe and
transitional Jinzhong sections along with other sections (e.g., Shangsi and Chaohu in South China, Guryul Ravine section in India and Buchanan Lake section in Canada), all showing positive values, indicative of predominantly atmospheric-derived
volcanic Hg. In contrast, d199Hg values at the second Hg peak, corresponding to the marine extinction horizon in Chahe and Jinzhong, are negative. This relationship indicates an elevated involvement of terrestrial sourced Hg into the terrestrial or
nearshore aquatic realm due to increased weathering after the collapse of terrestrial ecosystem. Our study suggests that the STLIP could have two pulses of volatile eruptions that released massive CO2 and Hg, resulting in two pulses of Hg enrichments
coupled with negative carbon isotopic excursions coinciding with end Permian terrestrial and marine extinction events. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Une nouvelle méthode développée par les chercheurs de la CGC utilise le mercure et les isotopes stables du mercure comme empreinte digitale pour
les périodes de volcanisme considérablement accru dans l'histoire de la Terre. Cela permet d'évaluer les impacts environnementaux des émissions de dioxyde de carbone volcanique et du réchauffement climatique qui en résulte dans le temps, pour aider à
mieux comprendre la réponse des systèmes terrestres au réchauffement climatique rapide. Cet article a appliqué cette méthode à la plus grande extinction de l'histoire de la Terre qui s'est produite il y a 252 millions d'années et montre l'extinction
synchrone de la vie terrestre et marine en réponse au réchauffement climatique induit par les volcans. |
| GEOSCAN ID | 329375 |
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