Author/Authors :
Lerouge، نويسنده , , C. and Vinsot، نويسنده , , A. and Grangeon، نويسنده , , S. and Wille، نويسنده , , G. and Flehoc، نويسنده , , C. and Gailhanou، نويسنده , , H. and Gaucher، نويسنده , , E.C. and Madé، نويسنده , , B. and Altmann، نويسنده , , S. and Tournassat، نويسنده , , C.، نويسنده ,
Abstract :
In the pore water chemistry model of the Callovian-Oxfordian clay formation, the divalent cations Ca, Mg, and Fe are controlled by equilibrium reactions with pure carbonates: calcite for Ca, dolomite for Mg, and siderite for Fe. Results of a petrological study and computing of the Ca/Mg and Ca/Fe activity ratios based on natural pore water chemistry provide evidence that equilibrium with pure calcite and pure dolomite is a reasonable assumption for undisturbed pore waters; on the other hand, siderite cannot be considered at equilibrium with pore waters at the formation scale.
