Paleohydrogeology of the Simpevarp area, southeastern Sweden, as evidenced by stable isotopes in fracture minerals

摘要

Fracture calcite, pyrite, barite and gypsum have been analysed for stable isotopes in order to gain knowledge of the low temperature evolution of the Simpevarp area, south-eastern Sweden. The different fracture filling generations show changing isotope signatures with time, indicating successively lower temperatures, and increased organic and microbial influence. Proterozoic calcite and pyrite have hydrothermal signatures while Paleozoic calcite and pyrite show signs of organic influenced fluids and some in situ microbial activity at lower T°. Calcite and pyrite precipitated from the end of Paleozoic until recent may have precipitated from fluids in equilibrium with present day groundwaters at ambient temperatures.