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TitreCompositional variation of siderite and its significance in deciphering the diagenetic evolution of the Lower Cretaceous sedimentary system of the Scotian Basin
TéléchargerTéléchargements
AuteurPe-Piper, G; Piper, D J W; Chavez, I; Zhang, Y; Wisen, J
SourceCommission géologique du Canada, Dossier public 7785, 2015, 323 pages, https://doi.org/10.4095/296912 (Accès ouvert)
Image
Année2015
ÉditeurRessources naturelles Canada
Documentdossier public
Lang.anglais
DOIhttps://doi.org/10.4095/296912
Mediaen ligne; numérique
Formatspdf
ProvinceRégion extracotière de l'est
Lat/Long OENS-64.0000 -53.0000 45.0000 43.0000
Sujetsgrès; lithologie; pétrographie; pétrologie du sediment; minéraux détritiques; s l dérite; cimentation; débris; diagenèse; paragenèse; géochimie des éléments en trace; géochimie des éléments majeurs; analyses structurales; interpretations structurelles; Crétacé inférieur; microscopie électronique à balayage; analyses par microscope électronique; Formation de Lower Missisauga ; Puit Balmoral M-32 ; Puit Cohasset A-52 ; Puit Como P-21 ; Puit Glenelg E-58 ; Puit Panuke B-90 ; Puit Sable Island C-67 ; pétrologie ignée et métamorphique; géologie marine; sédimentologie; géochimie; géologie structurale; Mésozoïque; Crétacé
Illustrationslocation maps; photomicrographs; stratigraphic columns; tables; plots; ternary diagrams
ProgrammeAnalyse de bassin et ressources géoscientifiques, Géoscience en mer
Diffusé2015 07 29
Résumé(disponible en anglais seulement)
Diagenetic siderite is widespread in the Scotian Basin with age ranging from sea-floor diagenetic to among of the last diagenetic products. Through the use of minor element chemistry five types of siderite have been identified. The relative ages of these five types of siderite have been established using their textural relationships in back-scattered electron (BSE) images, and through the use of petrographic microscopy. The studied siderites show extensive substitution of Mn and Mg and to a lesser extent of Ca for Fe, with the substitution of Mn for Fe being the most common in certain wells. Factors that may influence the chemistry of the diagenetic siderite include: chemistry of the circulating fluids, lithofacies, pre-existing detrital and diagenetic minerals, and availability of permeability. All these factors seem to have played a role in the chemistry of the studied siderites. The two competing mechanisms to produce the observed siderite chemical variability are regional basin hydrology and bio-mineralisation. Recrystallisation and re-precipitation of siderite are ubiquitous in most studied samples. They seem to be closely related with various dissolution events, syn-sedimentary deformation, and late regional salt tectonics. Of the dissolution events, late dissolution is especially enhanced in certain samples, and suggests the presence of very corrosive pore fluids. The best explanation for our data sets is the involvement of a variety of hydrogeological events. Factors that might have influenced the onset of these events include: regional tectonics, and in particular salt tectonics, transport of hydrocarbons, and overpressure, in addition to sea-level changes. Chemical evidence from siderite and associated minerals suggests that the circulating fluids that have influenced the precipitation of particular types of siderite must have changed drastically through time both in their chemistry and their temperature.
Résumé(Résumé en langage clair et simple, non publié)
Ce fichier ouvert présente des données sur la répartition de la sidérite minérale dans les grès des réservoirs du bassin Scotian. Siderite est souvent un indicateur de bonne porosité.
GEOSCAN ID296912