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New Late Triassic-earliest Jurassic magneto-biostratigraphic data have been obtained from three overlapping sections in the Southern Alps, Italy (Costa Imagna, Brumano, Italcementi Quarry), composed of~520 m of shallow-marine carbonates outcropping in stratigraphic continuity. Characteristic magnetic components of presumed depositional age record a sequence of 9 normal and reverse polarity magnetozones (as defined by at least three stratigraphically superposed samples) linked by conodont and palynofloral evidence from this study and the literature to Rhaetian to Triassic-Jurassic boundary age. This represents a significantly larger number of polarity zones than previously recognized in more condensed Rhaetian sections from the literature, and by inference represents more time. These data are placed in a broader Late Triassic temporal framework by means of correlations to published magneto-biostratigraphic data from the Tethyan marine Pizzo Mondello section and the Newark astronomical polarity time scale (APTS). This framework is consistent with a position of the Norian-Rhaetian boundary (as defined at Brumano and Pizzo Mondello by the first appearance of Misikella posthernsteini) within Newark magnetozones E17r-E19r in the~207-210 Ma time interval, in basic agreement with the position originally estimated in the Newark using pollen biostratigraphy (E18 at 208-209 Ma). This framework is also consistent with the position of the TriassicJurassic boundary interval (placed at Italcementi Quarry at the acme of Kraeuselisporites reissingeri coincident with a negative carbon isotope excursion) correlative to just above Newark magnetozone E23r and just below the oldest CAMP lavas dated at~202 Ma. Hence, we estimate the duration of the Rhaetian to be~5.5-8.5 Myr (or even longer if the Triassic-Jurassic boundary is instead placed above the negative carbon isotope excursion as at Kuhjoch, which is the designated GSSP for the base of the Hettangian), and encompassing 9 magnetozones. This duration contrasts with a duration of~2 Myr and only~4 magnetozones in several alternative published magneto-biostratigraphic schemes.

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