K-Ar isotope analyses from the Siljan Ring meteorite impact structure, Sweden

Abstract
K-Ar isotope analyses of pseudotachylite melt samples from within the Siljan structure yield an average age of 345 Ma, while analyses of dolerites from the deep well at Gravberg render ages decreasing with depth (926–789 Ma) and show no apparent sign of meteorite impact influence on the age of the samples. The ages of two dolerites within the structure of 1000 and 1087 Ma, respectively, are in accordance with ages for dolerite dikes outside the impact area.