Neoflabellinids (benthic foraminifers) from the Upper Coniacian and Lower Santonian at Olazagutia, Navarra province, Spain; taxonomy and correlation potential

The interval studied comprises a 30-m-thick section of uppermost Coniacian and Lower Santonian strata representing the upper part of the Pseudotextularia nuttalli and lower part of the Sigalia carpatica heterohelicid (planktonic foraminifer) zones. The Coniacian/Santonian boundary as defined by the first occurrence of the inoceramid species Platyceramus undulatoplicatus (Roemer) falls within the lower part of the Sigalia carpatica Zone. Neoflabellina is represented by N. suturalis, N. praerugosa, N. gibbera, N. praecursor and indeterminate forms. The first occurrences of N. gibbera and N. praecursor are significant proxies for the Coniacian/Santonian boundary.