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TitreOccurrence and distribution of barite and sphalerite cement in the Mesozoic sandstones of the Scotian Basin
TéléchargerTéléchargements
AuteurPe-Piper, G; Piper, D J W; Zhang, Y; Chavez, I
SourceCommission géologique du Canada, Dossier public 7560, 2014, 340 pages, https://doi.org/10.4095/293608
Année2014
ÉditeurRessources naturelles Canada
Documentdossier public
Lang.anglais
DOIhttps://doi.org/10.4095/293608
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; barytine; sphalérite; grès; 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 Wenonah J-75 ; Puit South Desbarres O-76 ; Puit Sable Island C-67 ; pétrologie ignée et métamorphique; géologie marine; sédimentologie; géochimie; géologie structurale; Mésozoïque; Crétacé
Illustrationslocation maps; photomicrographs; stratigraphic columns; tables
Consultation
Endroit
 
Bibliothèque de Ressources naturelles Canada - Ottawa (Sciences de la Terre)
 
ProgrammeAnalyse des bassins frontaliers, Les géosciences pour les nouvelles sources d'énergie
Diffusé2014 02 14
Résumé(disponible en anglais seulement)
Cementation of sandstone by minor barite and sphalerite is widespread in the Scotian Basin at burial depths > 2 km. These minerals provide further constraints on diagenetic processes and the nature of reservoir-quality risk in the exploration of this basin. This report documents the mode of occurrence, geochemistry, and paragenetic sequence of diagenetic barite and sphalerite and the structural character of veins of these minerals. The texture and geochemistry of these minerals were analysed by scanning electron microscopy and electron microprobe on samples from conventional core from 17 wells, sampling the geographic and stratigraphic range of the basin. Barite and sphalerite post-date silica and carbonate cementation, occurring in veins or occupying secondary porosity. They occur with diagenetic chlorite, pyrite, and titania minerals. Sphalerite is common in Tithonian rocks of the Eastern Scotian Basin and in Early Cretaceous rocks of the Central Scotian Basin. Barite is also common in the Eastern Scotian Basin, particularly in the Tithonian, but is less common and shows no systematic variation with stratigraphy in the Central Scotian Basin. Late barite veins cut Lower Cretaceous sandstones in the wells Wenonah J-75, South Desbarres O-76, and Onondaga O-95. The Sable Island C-67 well contains an unusual diagenetic assemblage including kutnohorite, late Mn-siderite and pyrite. Late dolomite is present in the Onondaga O-95 well. Mississippi-Valley-type ore deposits show many similarities to the barite-sphalerite diagenesis described here, in the association with dolomitizing and Mn-rich fluids, the evidence for synchronous emplacement of hydrocarbons, and the ability of the fluids to create secondary porosity in quartz. The distribution of barite and sphalerite can be used to constrain models of fluid flow in the basin.
Résumé(Résumé en langage clair et simple, non publié)
Dans le présent rapport nous décrivons en détail la répartition de la barite diagénétique, de la sphalérite et d'autres minéraux diagénétiques de formation tardive, dans le bassin Scotian et nous interprétons leur paragénèse et de leur relation avec la charge en hydrocarbures. Un article connexe traitera des répercussions plus vastes de ces données.
GEOSCAN ID293608