Orbital calibration of the late Campanian carbon isotope event in the North Sea

A new record of carbon isotopes, nannofossil biostratigraphy, gamma-ray and Fe content variations is presented for the upper Campanian of the Adda-3 core, Danish Central Graben, North Sea. The studied interval provides a revision of previously assigned late Coniacian to early Santonian ages. New biostratigraphic data indicate a late Campanian age for the 60m thick studied interval. The Late Campanian Event (LCE) is well recorded by a 1.5 parts per thousand negative excursion in the bulk delta C-13, along with two stepwise pre-excursion negative shifts (defining the pre-LCE). The amplitude of the LCE appears higher in the North Sea than in other areas as seen from the correlation to Germany, the UK and France. This correlation allows identification of a new 0.4 parts per thousand negative excursion (defined as the conica event). Fe and gamma-ray variations are used to calibrate the record with cyclostratigraphy. Fourteen 405 kyr cycles identified in the upper Campanian of Adda-3 can be correlated to North Germany. The compilation of previous results from North Germany and correlation to Adda-3 shows that the Boreal upper Campanian spans a total of 17 cycles each of 405 kyr; that is, 6.885myr. The duration of the LCE is estimated to be c. 1 myr at Adda-3 and in North Germany.