A geomagnetic polarity stratigraphy for the Middle and Upper Ordovician

Magnetostratigraphic studies of the Ordovician provide evidence for nature core-mantle boundary interactions, and means dating correlation across differing environmental regimes. We new magnetostratigraphic data from Middle Upper Ordovician, compiling this into a polarity chronostratigraphic scale Dapingian to Hirnantian interval. The are derived Backside Beck Cheney Longville sections in Britain, Mójcza section Poland two cores Lithuania. chronology is provided by existing biostratigraphy, principally based on chitinozoans conodonts Ordovician. Correlations between supported carbon isotope stratigraphy linked Baltic isotopic zonations, along with lithological local magnetic susceptibility correlations Polish cores. palaeomagnetic signal carried both haematite magnetite, dominating red-coloured lithologies (marls limestones) magnetite non-red mudstones limestones. A positive reversal test (class C) fold tests validation isolation primary signal. Palaeomagnetic directions were re-oriented using Kiaman-age Brunhes overprints. These datasets combination provides near-complete through Brief normal-polarity magnetozones extend well later parts what has been considered Moyero Superchron, which started late Tremadocian. Reversal frequencies mid 1.7 1.5 Myr?1 respectively, although that may be an underestimate.