End-Cretaceous akaganéite as a mineral marker of Deccan volcanism in the sedimentary record - Sorbonne Université Accéder directement au contenu
Article Dans Une Revue Scientific Reports Année : 2017

End-Cretaceous akaganéite as a mineral marker of Deccan volcanism in the sedimentary record

Résumé

An enigmatic chloride-rich iron (oxyhydr)oxide has been recently identified together with mercury anomalies in End-Cretaceous marine sediments coeval with the Deccan Traps eruptions. The mineral was observed in Bidart (France) and Gubbio (Italy), suggesting a widespread phenomenon. However, the exact nature and origin of this Cl-bearing mineral remained speculative. Here, we characterized the accurate composition and nanostructure of this chloride-rich phase by using micro-Raman spectroscopy, Transmission (TEM) and Scanning (SEM) Electron Microscopy on Focused Ion Beam foils. We also provide new evidence of its occurrence in Zumaia, a reference KPg section from Spain. Results confirm akaganéite (β-FeOOH) as the main phase, with chloride content of 3–5 atomic weight %. Akaganéite particles are constituted by the aggregation of nanorods of akaganéite. Internal structures contain empty spaces, suggesting formation in a low-density (atmospheric) environment. This new mineralogical evidence supports the hypothesis that the observed akaganéite was formed in the Deccan volcanic plume and was transported to the Atlantic and Tethysian realms through the stratosphere. Therefore, akaganéite provides a potential new sedimentary marker to identify the imprint of the Deccan eruptions in the stratigraphic record and is evidence of volcanic halogen degassing and its potential role for the Cretaceous-Tertiary mass extinction.
Fichier principal
Vignette du fichier
s41598-017-11954-y.pdf (5.6 Mo) Télécharger le fichier
Origine : Publication financée par une institution
Loading...

Dates et versions

hal-01609283 , version 1 (03-10-2017)

Licence

Paternité

Identifiants

Citer

Eric Font, Julie Carlut, Céline Remazeilles, Tamsin A Mather, Anne Nédélec, et al.. End-Cretaceous akaganéite as a mineral marker of Deccan volcanism in the sedimentary record. Scientific Reports, 2017, 7, pp.11453. ⟨10.1038/s41598-017-11954-y⟩. ⟨hal-01609283⟩
669 Consultations
249 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More