Carregant...
Fitxers
Tipus de document
ArticleVersió
Versió acceptadaData de publicació
Llicència de publicació
Si us plau utilitzeu sempre aquest identificador per citar o enllaçar aquest document: https://hdl.handle.net/2445/218702
Iron-carbonate concretions with inverse magnetic fabrics; a record of environmental changes in the middle Eocene marine marls of the Southern Pyrenees?
Títol de la revista
Director/Tutor
ISSN de la revista
Títol del volum
Recurs relacionat
Resum
This paper deals with the detailed analyses of magnetic fabrics accompanied by stable isotopic composition and microscopic observations in centimetric and metric scale authigenic carbonate concretions embedded in the Eocene flysch deposits of the Southwestern Pyrenees south of the cleavage front. Sampling was focused in the carbonatic concretions (in both metric and centimetric scale), in the marls lateral and nearby to the concretions and in the distant marls from the concretions. The inverse magnetic fabrics (kmax axes cluster perpendicular to bedding plane) detected in the concretions constitute a fast methodology to uncover their authigenic origin. The subfabric analyses indicate that magnetite is present in all four types of samples with normal magnetic fabric (kmin axes perpendicular to bedding). Paramagnetic fabric (low temperature anisotropy of magnetic susceptibility when magnetic susceptibility increases ~3.8 times the one at room temperature) parallels the room temperature magnetic fabric. The microscope observations reveal that iron-enriched dolomite is the main carrier of the inverse fabric in the dolomitic concretions at room temperature. The stable isotopic composition reveals minor differences between the Eocene flysch and the carbonate
concretions and with previous data, suggesting a marine pore water origin due to bacterial activity during burial
Matèries
Matèries (anglès)
Citació
Citació
OLIVA-URCIA, Belén, LARRASOAÑA, Juan c., TRAVÉ I HERRERO, Anna, GARCÉS CRESPO, Miguel, SIERRA-CAMPOS, P, PUEYO, Emilio, CALVÍN, P. Iron-carbonate concretions with inverse magnetic fabrics; a record of environmental changes in the middle Eocene marine marls of the Southern Pyrenees?. _Journal of Iberian Geology_. 2024. Vol. 1-23. [consulta: 29 de gener de 2026]. ISSN: 1698-6180. [Disponible a: https://hdl.handle.net/2445/218702]