Authigenic 10Be/9Be ratio provides clear evidence of the MBB in Montalbano Jonico. The MBB is characterized by a twofold increase of the atmospheric 10Be production. The Matuyama–Brunhes boundary (MBB) occurs at the late MIS 19c – MIS 19b periods. High-resolution δ18O data demonstrate large oscillations during the MIS 19a interval. The atmospheric 10Be-production rates during the MBB show rapid variations.