Impact of basin burial and exhumation on Jurassic carbonates diagenesis on both sides of a thick clay barrier (Paris Basin, NE France)

Abstract

Several diagenetic models have been proposed for Middle and Upper Jurassic carbonates of the eastern Paris Basin. The paragenetic sequences are compared in both aquifers to propose a diagenetic model for the Middle and Late Jurassic deposits as a whole. Petrographic (optical and cathodoluminescence microscopy), structural (fracture orientations) and geochemical (δ 18 O, δ 13 C, REE) studies were conducted to characterize diagenetic cements, with a focus on blocky calcite

Diagenetic effects of compaction on reservoir properties: The case of early callovian “Dalle Nacrée” formation (Paris basin, France)

“…GN1). Carpentier et al (2014) also observed contemporaneous syntaxial cements and blocky calcite -based on similar cathdodoluminescence patterns. Furthermore, the syntaxial overgrowth calcite cements have been demonstrated to precipitate for a long time overlapping most of the other diagenetic phases (e.g.…”

“…Since this paper focuses on the blocky calcite cement, they have been further subdivided on the basis of their cathodoluminescence characteristics (i.e.. BC1, BC2, BC3, see below) (cf. Carpentier et al, 2014).…”

“…The petrography and luminescence patterns of the blocky calcite cement suggest precipitation in a burial setting (c.f. Vincent et al, 2007;Brigaud et al, 2009;Carpentier et al, 2014). Blocky calcite cement fill up free space around spalled coated grains and fractures created by mechanical compaction.…”

“…The three main reservoir units can be subdivised further into sub-units called "pseudo-parasequences" on the basis of local discontinuities of autocyclic origin, in relation to the migration of oolitic sedimentary bodies (Granier, 1994). Noteworthy is that the "Dalle Nacrée" reservoirs have been affected by a variety of diagenetic processes early after deposition and later during further burial (Javaux, 1992;Carpentier et al, 2014). Diagenesis has therefore major impacts on the reservoir properties and overall heterogeneities of this formation.…”

Elucidating the formation of terra fuscas using Sr–Nd–Pb isotopes and rare earth elements

“…Nevertheless, the Ce anomalies of the different limestone are variable, range between 0.5 and 0.8 and are higher than those found in carbonates, which formed in well-oxygenated seawater (<0.4) (Olivier and Boyet, 2006). According to Carpentier et al (2014), these variable Ce anomalies might be related to reloading of the Middle Jurassic limestone aquifers by mixed marine-meteoric waters during burial in a reducing environment, which partly erased the negative seawater-derived Ce anomaly and increased the REE contents in the limestones. We Fig.…”