Until now, the crystalline basement beneath the southern Upper Rhine Graben (URG) was totally unknown. Only recently, in the framework of an Enhanced Geothermal System (EGS) exploration, two deep boreholes were drilled near Basel (Kleinhüningen (Basel-1) and Otterbach), reaching granitoid basement below 2.6 km.
We propose a comprehensive basic research on the present fluid-rock interaction and the past-to-present evolution of fluid-rock interaction in the basement rocks and their Permian/Triassic sedimentary cover in the southern URG and adjacent regions. For this purpose, we will use samples of basement rocks and Permian / Triassic sediments of the EGS site near Basel and from the southern Schwarzwald, as well as the deep fluids produced by the former. Through the proposed research, we will try to understand and quantify origin and evolution of fluids and fluid-rock interaction in basement rocks and their sedimentary cover in the southern URG Our aims are to characterise the basement beneath the southern URG, to understand 'fossil' fluid-rock interaction in the basement, to constrain fluid exchange between basement and sedimentary cover, and to evaluate the contribution of microorganisms to present and past fluid composition.
This will be achieved in the course of an integrated study using conventional petrological-geochemical techniques combined with methods to detect organic matter.