Callovian (upper Middle Jurassic) magnetostratigraphy and its correlation to Pacific marine magnetic anomalies

A nearly continuous composite geomagnetic polarity reference sequence spanning the latest Bathonian (Discus Zone) through entire Callovian and into the earliest Oxfordian (Mariae and Cordatum zones) was complied from 14 ammonite- and/or brachiopod-zoned sections from England, France and Southern Germany. Additional inter-section correlations and adjustment for local hiatuses were provided by basinal sequence stratigraphy. The Callovian is dominated by normal polarity, with three clusters of relatively brief reversed-polarity zones. A subset of the 391 samples were filtered according to magnetic behavior, and the highest quality suite (representing outcrops) produced an average paleopole of 66°N, 171°E (δp=11°, δm=16°) for England and of approximately 75°N, 149°E (δp=11°, δm=15°) for France. The main aspects of the magnetostratigraphy pattern mirror the general trends of Callovian-age marine magnetic anomalies in the Western Pacific as determined by deep-tow magnetic surveys in the Pacific basin. This geomagnetic polarity reference sequence, scaled with cycle stratigraphy where available, confirms and calibrates the main features of the Pacific marine magnetic anomaly model from anomaly M37 and older. The top of the Callovian correlates with the marine magnetic anomaly M37n (tentatively to the lower part of subchron M37n.1n) and the base of the Callovian is within marine magnetic anomaly M39n.