Walraevens,K., Cardenal-Escarcena,J. and Van Camp,M.(2007): Reaction transport modelling of a freshening aquifer (Tertiary Ledo-Paniselian Aquifer, Flanders-Belgium). Applied Geochemistry, 22, 289-305.

『脱塩している帯水層(フランドル・ベルギーの第三紀Ledo-Paniselian帯水層)の反応輸送モデリング』


Abstract
 The semi-confined Ledo-Paniselian (Eocene) Aquifer in Flanders, Belgium is recharged in the areas with higher topography, where it is covered by the Bartonian Clay. Initial conditions in these sediment were marine. Hydrogeochemical modelling of the groundwater type distribution in the aquifer with a reaction transport model considers recharge of fresh CaHCO3 water』 by downward flow through the overlying clay. In the aquifer, in an upstream direction, progressively more freshened water types are found. A typical NaHCO3 type occurs upstream of the brackish-fresh water interface. The different stages of cation exchange produce a chromatographic sequence of groundwater types, which agrees well with observations. Cation exchange processes occurring mainly in the percolated clay, result in a Na+ increase, and peaks of K+, NH4+ and Mg2+ in the aquifer, which are spatially separated as a result of groundwater flow. Calcite equilibrium, gypsum dissolution in the clay and sulphate reduction in the aquifer have also been included in the modelling.』

1. Introduction
2. Geology and hydrogeology of the Ledo-Paniselian Aquifer
3. Hydrogeochemical evolution
4. Exchangeable cations in the Bartonian Clay and exchange parameters
5. Geochemical modelling of freshening of the Bartonian Clay and Ledo-Paniselian Aquifer - Development of a chromatographic pattern
 5.1. Hydraulic schematization
 5.2. Chemical model
 5.3. Freshening of the Bartonian
 5.4. Freshening of the Ledo-Paniselian Aquifer
 5.5. Freshening of the aquifer in the northern part
6. Conclusions
Acknowledgements
References


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