| Titre | Temperature and basinal fluid controls on feldspar diagenesis, Lower Cretaceous sandstones, Scotian Basin, Canada |
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| Auteur | Pe-Piper, G; Piper, D J W |
| Source | Marine and Petroleum Geology vol. 141, 105704, 2022 p. 1-22, https://doi.org/10.1016/j.marpetgeo.2022.105704 |
| Image |  |
| Année | 2022 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200401 |
| Éditeur | Elsevier |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1016/j.marpetgeo.2022.105704 |
| Media | en ligne; numérique |
| Formats | pdf |
| Province | Nouveau-Brunswick; Nouvelle-Écosse; Terre-Neuve-et-Labrador; Région extracotière de l'est |
| SNRC | 1A; 1B; 1C; 1D; 11; 21A; 21B; 21G; 21F; 21H; 21I; 21J; 21K; 21N; 21O; 21P; 20D; 10 |
| Lat/Long OENS | -66.0000 -52.0000 47.0000 42.0000 |
| Sujets | feldspath; albitisation; sel; tectonique du sel; inclusions fluides; Dissolution; géologie marine |
| Illustrations | cartes de localisation; échelles stratigraphiques; tableaux; diagrammes de phases; images; figures |
| Programme | Les géosciences pour les nouvelles sources d'énergie Analyse des bassins frontaliers |
| Diffusé | 2022 04 20 |
| Résumé | (disponible en anglais seulement)
The passive-margin Scotian Basin accumulated thick Upper Jurassic-Lower Cretaceous deltaic sandstones and shales, which were influenced by high heat flow in the
mid-Cretaceous and deformed by salt tectonics. This study takes advantage of the complex thermal history and record of saline fluid flow in the basin to determine the relative importance of burial depth, temperature, salinity of basinal brines,
overpressure, and sandstone permeability in controlling the dissolution of detrital feldspar and growth of authigenic K-feldspar and albite. Feldspar grains and volcanic lithic clasts from two transects, with differing thermal and salt tectonic
histories, were studied by scanning electron microscope (SEM) backscattered electron images, energy-dispersive spectroscopy, SEM cathodoluminescence (CL) imaging, and hot-cathode CL microscopy. Published fluid inclusion measurements are integrated
with burial history curves and timing of deformation on salt detachment surfaces to provides a new synthesis of the post-Jurassic thermal and saline fluid flow history of the basin. Surface-controlled dissolution of K-feldspar and growth of
authigenic K-feldspar rims occur from 1.5 to 3.1 km. More destructive transport-controlled dissolution, down to 3.9 km, is more effective in thick-bedded permeable sandstones that acted as fluid pathways. Albitization of detrital K-feldspar and sodic
plagioclase, and of feldspars in volcanic lithic clasts was facilitated by high Na+ content of formation waters migrating preferentially through such pathways at the time of silica and carbonate cementation, with strong albitization coinciding with
transport-controlled dissolution of K-feldspar. Authigenic albite partially fills pores created by K-feldspar dissolution. Overpressured conditions enhance albite authigenesis, as a result of slower fluid advection. Episodic release of hot, saline,
overpressured fluids in the zone of surface-controlled dissolution of K-feldspar favoured albitization but had no detectable effect on K-feldspar dissolution. Basin hydrology plays a definitive role in feldspar diagenesis, producing patterns that
cannot be interpreted as a simple consequence of temperature and activity of Na+. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Cette étude présente une nouvelle synthèse de l'évolution thermique des réservoirs d'hydrocarbures de grès du bassin Scotian et des mécanismes
qui régissent la dissolution et la précipitation des minéraux de feldspath dans le grès. |
| GEOSCAN ID | 327210 |
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