Abstract

APTICORE at the Cismon Valley (Belluno Basin, Southern Alps) penetrated 131.8 m of pelagic limestones, marlstones and black shales. The cored interval extends from the upper Albian to the lower upper Hauterivian. Freshly cored material and logs from the Cismon drill site provide a very informative record. Detailed, multidisciplinary studies show high and low frequency changes in lithologic, paleontologic, paleomagnetic, and geochemical records. Moderate to good preservation of calcareous and siliceous plankton and palynomorphs allowed the identification of several calcareous nannofossil, planktonic foraminiferal, radiolarian and dinoflagellate events. Magnetostratigraphy is available for the entire interval and Chrons CM0 through CM9 were detected. Stable C and O, and Sr isotopes were analysed and chemostratigraphy of the Cismon core comprises both delta 13 C carb curve and the 87 Sr/ 86 Sr record. Integrated stratigraphy of the Cismon APTICORE resulted in the first coherent scheme derived from direct calibration of bio-, magneto-, and chemo-stratigraphy for the Upper Hauterivian-Aptian interval. In the upper portion of core, an unconformity removed part of the upper Aptian, the lower Albian and most of the middle Albian. The Upper Hauterivian is characterized by folding and some slumps resulting in high sedimentation rates. The uppermost Hauterivian consists of red pseudonodular limestone with low sedimentation rate. We propose the Cismon core as a "reference section" for the Barremian-Aptian at low latitudes, containing both a complete carbonate and organic carbon record through the critical black shale intervals.

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