Anhydrite-gypsum transition in the argillites of flooded salt workings in eastern France
| Titre | Anhydrite-gypsum transition in the argillites of flooded salt workings in eastern France |
|---|---|
| Titre court | Anhydrite-gypsum transition in the argillites of flooded salt workings in eastern France |
| Type de document | article |
| Auteur(s) | Boidin, E. Homand, F. Thomas, F. Yvon, J. |
| Date | 2009 |
| Titre de la publication | Environmental Geology (Berlin) |
| Volume | vol. 58 |
| N° | 3 |
| N° de page(s) | 531-542 |
| Résumé | This study aims at understanding the physico-chemical interactions between the saturated brine and the rocks enclosing the underground salt workings in Lorraine (eastern France). These anhydrite-rich and argillaceous rocks were characterized in terms of mineralogy, micro-texture and connected porosity. Then, the two main lithofacies, massive anhydrite and anhydrite-rich argillite, were immersed in brine during more than 1 year. During this batch experiment, the argillites were affected by macroscopic splitting, contrarily to the massive anhydrite. Micro-texture and brine chemical analyses clearly show the swelling due to the hydration of anhydrite into gypsum inside the argillites, whereas hydration occurs superficially on the massive anhydrite, due to its very low permeability. Anhydrite–gypsum transformation is promoted by the presence of dissolved strontium and potassium in saturated brine. The low activity of water in saturated brine does not allow the clay fraction to swell significantly during the experiment. Thus, the expansion resulting from the hydration of anhydrite into gypsum might be responsible of the splitting of argillite in a saturated brine environment. The superficial anhydrite hydration on massive anhydrite can be explained by the low amount of connected porosity (less than 1%). |
| ISSN | 0943-0105 |
| DOI | 10.1007/s00254-008-1528-1 |
| Langue | Anglais |
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