Saline groundwater and brines in crystalline rocks: the contributions of John Andrews and Jean-Charles Fontes to the solution of a hydrogeological and geochemical problem

Investigations into the suitability of crystalline rock for the long-term containment of high level nuclear waste were initiated in the early 1970s. A significant task was thereby to assess fluid movements to and from potential repositories. This paper focuses on the contributions of J.N. Andrews and J.-Ch. Fontes to this problem and presents some aspects of their work on fluids in crystalline rock environments. Waste repository studies saw major progress with the initiation of the Stripa project in 1977. Andrews joined this project during the first year and participated until its closure in the late 1980s. Fontesʹ involvement began during the second phase of the project, after the first ideas about the geochemistry and evolution of groundwater encountered in the Stripa granite had been developed. The problems associated with dating of such hydrogeological systems, their geochemical evolution and the question of origin of dissolved salts occupied both of them and their co-workers. Those privileged to participate in the long and lively discussions will remember these times as extremely fruitful. The results are documented in a multitude of international studies where the Stripa ideas were further developed and tested—not only in Sweden. Based on the data from Swedish and other environments with crystalline rock brines, Andrews, Fontes and others had recognised the need to develop at least one additional project designed to clarify major points of uncertainty regarding the age and evolution as well as the origin of saline fluids found in most crystalline rock environments. The untimely death of these two applied geochemists is the reason why these discussions have not (yet) been concluded.