Distribution of diagenetic alterations in siliciclastic shoreface deposits within a sequence stratigraphic framework: Evidence from the Upper Jurassic, Boulonnais, NW France - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Sedimentary Research Année : 2005

Distribution of diagenetic alterations in siliciclastic shoreface deposits within a sequence stratigraphic framework: Evidence from the Upper Jurassic, Boulonnais, NW France

Jean-Noël Proust
K. Al-Ramadan
  • Fonction : Auteur
S. Morad
  • Fonction : Auteur
I. Al-Aasm
  • Fonction : Auteur

Résumé

The distribution of diagenetic alterations in Upper Jurassic, siliciclastic shoreface sediments from NW France has been linked to the sequence stratigraphic framework. Calcite cement in mudrocks and sandstones of the transgressive (TST) and lower part of the highstand (HST) systems tracts is microcrystalline and occurs as continuously cemented layers and stratabound concretions. The average delta(18)O(V-PDB) (-2.6%omicron) and Sr-87/Sr-86 (0.7078) compositions of microcrystalline calcite indicate precipitation from largely marine pore waters. >Calcite cement in sandstones of the forced regressive wedge (FRWST) and lowstand (LST) systems tracts is poikilotopic and occurs mainly as stratabound concretions. Complete dissolution of the carbonate grains and concomitant precipitation of poikilotopic calcite cement with low average delta(18)O (-5.3%omicron) and radiogenie Sr-isotope (0.70882) signatures suggest incursion of meteoric waters into sandstones during relative sea-level lowstand. The poorly lithified sandstones interbedded with sandstones cemented by poikilotopic calcite concretions display evidence of diagenesis under episodes of and to semiarid paleoclimate, including: (i) partial cementation by opal, chalcedony, gypsum, and minor vadose calcite cement, (ii) mechanically infiltrated clays and Fe-oxides, and (iii) secondary porosity owing to partial dissolution of carbonate grains. The integration of diagenesis into sequence stratigraphy allows better elucidation and prediction of the spatial and temporal distribution of diagenetic alterations and related reservoir-quality modifications in shoreface sediments

Domaines

Stratigraphie
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Dates et versions

hal-00085006 , version 1 (11-07-2006)

Identifiants

  • HAL Id : hal-00085006 , version 1

Citer

Jean-Noël Proust, K. Al-Ramadan, S. Morad, I. Al-Aasm. Distribution of diagenetic alterations in siliciclastic shoreface deposits within a sequence stratigraphic framework: Evidence from the Upper Jurassic, Boulonnais, NW France. Journal of Sedimentary Research, 2005, 75 (5), pp.943-959. ⟨hal-00085006⟩
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