Jurassic), a deep saline aquifer, show some interest as : (1) it is exploited for geothermal energy and (2) this formation is considered for CO2 geological storage. As such, the Oolithe Blanche Formation (mid. maps of geological sections in pocket.Previous studies in the Paris basin, inherited from oil exploration, led to the modelling of filling and temporal evolution of the basin and the determination of geological formations available for CO2 geological storage or geothermal energy exploitation. Peritidal lithification and dolomitization, along with minor shallow-burial lithification, determined the final appearance of the rocks deeper burial and re-exposure events resulted in only a diffuse overprinting of all lithofacies. The spectrum of calcite cements, mudstones and dolomites represents a protracted history of diagenesis, which includes: (1) synsedimentary peritidal lithification, erosion and dolomitization (2) possible shallow-burial meteoric lithification and alteration of metastable carbonates (3) deep-burial lithification and dolomitization and (4) cementation and dedolomitization related to uplift. The facies-specific nature of ooid mineralogy and morphology suggests that local environmental conditions strongly influenced ooid formation, particularly turbulence and sea floor topography. Radial ooids in subtidal grey oolite were Mg calcite only and underwent progressive alteration during burial to give rise to a variety of cortical fabrics, ranging from radial to blocky calcite. Concentric ooids in intertidal brown oolites were originally bimineralic aragonitic laminae are now blocky calcite and laminae of fibrous and micritic Mg calcite have altered to calcite with well-preserved fabrics. These differences may reflect narrower shelf widths lower rates of sedimentation and lower amplitudes of relative sea-level rise on the northeastern margin of the North American craton compared to the western margin. These Grand Cycles are distinct from western North American cycles because they are composed almost entirely of peritidal sediments thinness of the cycles and restricted areal occurrence. These two assemblages together form Grand Cycles that reflect the complex interplay of sea-level eustasy and regional variations in sedimentation and environmental conditions. The lithofacies occur in two types of meter-scale assemblages: (1) predictable meter-scale, shallowing-upward cycles of parted limestone and shale deposited in the muddy tidal flats, which were largely controlled by variable rates of sedimentation and (2) unpredictable meter-scale assemblages of ooid calcarenite and carbonate laminite, which resulted from the sporadic but frequent migration of the carbonate shoals. Siliciclastic sands and silts represent eolian deposits and reworking of nearshore siliciclastics. Both muddy tidal flats and carbonate sand shoals were sites of stromatolite and thrombolite mound growth. Parted limestones and grey shales were deposited on muddy tidal flats leeward of the carbonate shoals.
#Oolite subjected to diagenesis series#
Ooid calcarenites, carbonate laminites, and variegated shales together were deposited as a series of carbonate sand shoals in which the shallow-subtidal and intertidal zones were each regimes of in situ ooid formation and accumulation. The Port au Port Group is an outer shelf, peritidal carbonate and siliciclastic platform deposit composed of six lithofacies: (1) parted limestone (2) grey and variegated shale (3) ooid calcarenite (4) carbonate laminite (5) stromatolite and thrombolite mound and (6) mixed glauconitic sandstone and oolite. Neither the thesis nor substantial extracts from it may be printed or otherwise reproduced without the author's permission.
#Oolite subjected to diagenesis license#
PDF (Migrated (PDF/A Conversion) from original format: (application/pdf))Īvailable under License - The author retains copyright ownership and moral rights in this thesis. Sedimentology and diagenesis of middle and upper Cambrian platform carbonates and siliciclastics, Port au Port Peninsula, Western Newfoundland.ĭoctoral (PhD) thesis, Memorial University of Newfoundland.
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