SANTONIAN–CAMPANIAN BOUNDARY INTERVAL IN THE KYUNETSA SECTION, WESTERN SREDNOGORIE ZONE, BULGARIA

The Kyunetsa section, 2.5 km west of Kosharevo, exposes mainly pelagic Upper Cretaceous marly limestones and marls of the Srednogorie Zone, part of the intermediate Balkanides in Bulgaria. The Melove Formation of Coniacian to early Campanian age involves a prominent Santonian–Campanian boundary interval of grey and reddish sediments, including CORBs (Cretaceous Oceanic Red Beds). The base of the Campanian can be discerned in bed 7c by the first rare (single) occurrence of the nannofossil Broinsonia (Aspidolithus) parca parca. A positive carbon isotope peak below, and a field magnetic susceptibility peak above may enhance correlation to other Tethyan sites such as the proposed GSSP at Bottaccione (Italy), the Postalm section (Austria) and the Mudurnu–Göynük Basin (Turkey).