Reversed polarity characteristic magnetizations in the Albian Contessa section, Umbrian Apennines, Italy: implications for the existence of a mid-Cretaceous mixed polarity interval

Paleomagnetic and paleontologic data from the Valle della Contessa span a 14 m.y. gap in previous magnetostratigraphic sections and reveal several intervals of reversed characteristic remanent magnetization (ChRM) in limestones and marls of the Albian Marne a Fucoidi. Milankovitch-like bedding cyclicity can be used to tune the sedimentation rate and obtain estimates of the duration of the potential reversed intervals. Using these estimates, two of the potential reversed polarity intervals are of sufficient duration (>100 kyr) to be recognizable in both detailed stratigraphic sections and marine magnetic anomaly surveys. A primary magnetization model predicts that several intervals of reversed magnetization should be found near the boundary of the Biticinella breggiensis and Ticinella primula foraminiferal zones and within the Prediscosphaera cretacea nannofossil zone on a worldwide basis. -from Authors