GEOSCAN, résultats de la recherche


TitreCharacterization of sedimentary organic matter in recent marine sediments from Hudson Bay, Canada, by rock eval pyrolysis
AuteurHare, A H; Kuzyk, Z K; Macdonald, R M; Sanei, H S; Barber, D B; Stern, G S; Wang, F W
SourceOrganic Geochemistry vol. 68, 2014 p. 52-60,
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130404
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceQuébec; Ontario; Nunavut; Manitoba
SNRC43P; 33M; 44A; 43N; 44K; 54J; 55C; 55B; 45F; 35D; 35L; 35I; 46A
Lat/Long OENS -95.0000 -70.0000 65.0000 50.0000
Sujetspyrolyse; etudes isotopiques; géochimie organique; matières organiques; sédiments marins; dépôts terrigènes; biogéochimie; manganèse
Illustrationslocation maps; plots; graphs
Programmeadaptation et impacts sur l'environnement, environnement du nord, Géosciences de l'environnement
Résumé(disponible en anglais seulement)
A combination of Rock Eval pyrolysis and isotopic analyses is used to characterize the sources and distribution of organic matter in modern marine sediments from the subarctic Hudson Bay (including Hudson Strait and Foxe Basin), Canada. This approach reveals organic matter contributions from both marine and terrigenous sources, with spatial patterns and varying degrees of degradation that are consistent with inferences from traditional geochemical tracers for modern organic matter. Rock Eval 3 parameters characterize Hudson Bay organic matter with low hydrogen index, high oxygen index, and a high degree of residual carbon that suggests heavily reworked materials. Locations of higher primary productivity in Hudson Strait, Foxe Basin, the northeast and far west of Hudson Bay, and the concentration of watershed runoff in the southern part of Hudson Bay can be delineated using the ratios between hydrogen and oxygen indices, and from the distribution of labile organic carbon. Relatively high temperatures of peak hydrocarbon yield identify an advanced state of OM degradation or humic substances as important classes of organic carbon compounds in the majority of the sediment. Such highly degraded and oxygenated organic matter is unusual compared to that typically observed in other Arctic shelf seas and is consistent with a strong role for sediment and organic matter recycling in Hudson Bay. In the offshore region, the source of highly oxidized and labile organic matter identified by Rock Eval parameters is resolved with d13C and biomarker information that also permit examination of the sediment biogeochemical regime. This approach suggests that a distinct association with Mn-enriched sediment contributes to the oxidization signal by abiotic or biological Mn related processes. These interpretations extend the limited information available on using Rock Eval analyses to characterize organic matter in recently deposited marine sediments, and describe an important consideration to using this method in Mn-enriched environments.
Résumé(Résumé en langage clair et simple, non publié)
Cet article documente en détail la distribution de la matière organique contenu dans les carottes de sédiment de la Baie d'Hudson. Les résultats demontrent bien l'importance du recyclage de la matière organique dans le cycle du carbonne à l'intérieur du système sédimentaire.