Some conventional potassium–argon and ⁴⁰Ar/³⁹Ar age studies of glauconite

Summary 40 Ar/ 39 Ar age studies of some glauconites from well-known stratigraphical horizons reveal unexpectedly high ages compared with the conventional K–Ar age determinations. These have been interpreted in terms of nuclear and physico-chemical reactions sustained by the glauconites in the reactor. These impose severe limitations on the use of glauconite in the 40 Ar/ 39 Ar irradiation technique.