Evolution tectonique mÃ©so-cÃ©nozoÃ¯que du bassin de Paris: contraintes stratigraphiques 3D

Guillocheau, François; Robin, Cécile; Allemand, Pascal; Bourquin, Sylvie; Brault, Nicolas; Dromart, G.; Friedenberg, Roselyne; Garcia, Jean-Pierre; Gaulier, Jean-Michel; Gaumet, Fabrice; Grosdoy, Bernard; Hanot, Franck; Strat, Paul Le; Mettraux, Monique; Nalpas, Thierry; Prijac, Christophe; Rigollet, Christophe; Serrano, Olivier; Grandjean, Gilles

doi:10.1016/s0985-3111(00)00118-2

Cited by 108 publications

(5 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The studied area is located at the unconformity between the Paris Basin and the French Massif Central (FMC), about 200 km southeast of Paris. The Paris Basin is an intracratonic sedimentary basin that formed above Cadomian and Variscan basement rocks (Guillocheau, 2000). The FMC was structured during the Variscan orogeny (Lardeaux et al, 2014;Vialette, 1973).…”

Section: Geological Settingmentioning

confidence: 99%

Uranium incorporation in fluorite and exploration of U–Pb dating

et al. 2021

View full text Add to dashboard Cite

Abstract. The age of ore deposits constitutes a decisive element in understanding their formation. Deciphering their precise chronology may be a challenge in the absence of mineral phases that can be dated by conventional geochronometers. Fluorite is very common either as the major or accessory mineral in a wide variety of ores and may provide information regarding the origin and timing of mineralizing fluid flows. In this contribution, we explore U–Pb dating on fluorite crystals from the world-class carbonate strata-bound fluorite ore of Pierre-Perthuis in Burgundy (Morvan massif, France). The uranium distribution within fluorite is mapped using induced fission-track and synchrotron radiation X-ray fluorescence nano-imaging, showing that higher U content is measured in an overgrowth of fluorite (Flog) as a discrete band. Preservation of a micrometer-thick zonation in U, associated with other substituted elements such as Sr, Y, Fe and Zr, implies that neither solid-state diffusion nor dissolution–recrystallization occurred. These U-bearing external fluorite overgrowths contain solid inclusions of about 30 µm globular pyrite crystals with a mean δ34S of −23.6 ± 0.4 ‰V-CDT. We propose that the U incorporation in the fluorite lattice results from the development of a redox front during bacterial sulfate reduction. Flog generation sampled and analyzed by laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS) on four different crystals provides identical U–Pb ages within the limits of analytical uncertainty. Considered altogether, these four crystals yield an age estimate of 40.0 ± 1.7 Ma, not corrected for matrix-related elemental fractionation. Our results show that fluorite LA-ICP-MS U–Pb geochronology has potential for dating distinct crystal growth stages, although further research should be conducted to evaluate its accuracy.

show abstract

Section: Geological Settingmentioning

confidence: 99%

Uranium incorporation in fluorite and exploration of U–Pb dating

et al. 2021

View full text Add to dashboard Cite

show abstract

“…The Triassic was a period of tectonic inactivity which led to the formation of the Triassic peneplain (Bois et al 1980;Soulé de Lafont and Lhégu 1980). During Jurassic and Cretaceous times a marine transgression took place and a cover of marls and limestones of about 500 m was deposited (Lorenz 1968;Le Calvez et al 1969;Soulé de Lafont and Lhégu 1980;Guillocheau et al 2000). Finally, since the Tertiary the Morvan area remained exposed and subjected to erosion.…”

Section: Geological Setting and Field Datamentioning

confidence: 99%

Albitisation related to the Triassic unconformity in igneous rocks of the Morvan Massif (France)

Parcerisa

Thiry

Schmitt

2009

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

The Carboniferous Morvan Massif, in the northern part of the French Massif Central, consists of granite and some rhyolite. A Triassic erosional unconformity has developed on the massif which is covered by Mesozoic sediments of the Paris Basin. The igneous rocks of the Morvan Massif show a strong alteration with pseudomorphic replacement of the primary plagioclases into albite, pseudomorphic replacement of primary biotite into chlorite and minor precipitation of neogenic minerals like albite, chlorite, apatite, haematite, calcite and titanite. The geometry and arrangement of these alterations give significant constraints about their development. Some of the altered facies develop in a pervasive manner; others are restricted to centimetric to metric-wide joints that imply fluid-flow phenomena. Moreover, the alteration facies are arranged in a clear succession with strongly altered facies at the top and weakly altered facies towards the depth, which point to a genetic relationship with the Triassic unconformity. Regional distribution of the alterations, which affect the Carboniferous igneous and volcanic formations beneath the Jurassic sedimentary cover, also leads to associate these alterations with the Triassic unconformity. Dating of the alterations provides even a further constraint, alterations are of Triassic age, that means the same age as the unconformity. Taking into account all these geological constraints, it is proposed that albitisation of the Morvan Massif was developed under low temperature subsurface conditions in relation to the Triassic palaeosurface.

show abstract

“…The studied area is located at the interface between the Paris Basin and the French Massif Central (FMC), about km (Guillocheau, 2000). The FMC was structured during the Variscan orogeny (Lardeaux et al, 2014;Vialette, 1973).…”

Section: Geological Settingsmentioning

confidence: 99%

Uranium incorporation in fluorite and exploration of U-Pb dating

Lenoir¹,

Blaise²,

Somogyì³

et al. 2020

Preprint

View full text Add to dashboard Cite

Abstract. The age of ore deposits constitutes a decisive element in understanding their formation. Deciphering their precise chronology may be a challenge in the absence of mineral phases that can be dated by conventional geochronometers. Fluorite is very common either as the major or accessory mineral in a wide variety of ores and may provide information regarding the origin and timing of mineralizing fluid flows. In this contribution, we explore U-Pb dating on fluorite crystals from the world-class carbonate strata-bound fluorite ore of Pierre-Perthuis in Burgundy (Morvan massif, France). Uranium distribution within fluorite is mapped using induced fission-track and Synchrotron radiation X-Ray Fluorescence nano-imaging, showing that higher uranium content is measured in an overgrowth of fluorite (Flog) as a discrete band. Preservation of a micrometer-thick zonation in U, associated with other substituted elements such as Sr, Y, Fe and Zr implies that neither solid-state diffusion nor dissolution-recrystallization did occur. These U-bearing external fluorite overgrowths contain solid inclusions of about 30 µm globular pyrite crystals with a mean δ34S of −23.6 ± 0.4 ‰ V-CDT. We propose that the U incorporation in the fluorite lattice results from its reduction mediated by H2S release during bacterial sulphate reduction. Flog generation sampled and analyzed by LA-ICP-MS on four different crystals provides identical U-Pb ages within the limits of analytical uncertainty. Considered altogether, these four crystals yield an age estimate of 40.0 ± 1.7 Ma, not corrected for matrix-related elemental fractionation. Our results show that fluorite LA-ICP-MS U-Pb geochronology has potential for dating distinct crystal growth stages, although further research should be conducted to evaluate its accuracy.

show abstract

Evolution tectonique mÃ©so-cÃ©nozoÃ¯que du bassin de Paris: contraintes stratigraphiques 3D

Cited by 108 publications

References 90 publications

Uranium incorporation in fluorite and exploration of U–Pb dating

Uranium incorporation in fluorite and exploration of U–Pb dating

Albitisation related to the Triassic unconformity in igneous rocks of the Morvan Massif (France)

Uranium incorporation in fluorite and exploration of U-Pb dating

Contact Info

Product

Resources

About