Late Cenomanian to Middle Turonian high-resolution carbon isotope stratigraphy: New data from the Munsterland Cretaceous Basin, Germany

摘要

New high resolution carbon isotope stratigraphies from two basinal pelagic carbonate successions in northern Germany (Halle and Oerlinghausen, Munsterland Cretaceous Basin) resolve late Cenomanian to early Mid-Turonian carbon cycle variations at timescales of less than 100 kyr. Beside the major carbon isotope excursion of the late Cenomanian oceanic anoxic event (OAE 2), 11 small-scale distinct features are precisely resolved in the delta C-13 carbonate curve and related to boreal macrofossil zonations. The small-scale carbon isotope events correspond to secular delta C-13 carbonate variations identified previously in the English Chalk. The boreal high-resolution delta C-13 carbonate curve shows a detailed coincidence with two Tethyan delta C-13 curves from Italy, what demonstrates the interregional significance of the delta C-13 dates and allows their correlation within error limits of 40 kyr. Furthermore, the new delta C-13 curve enables the calibration of boreal and tethyan macro- and microfossil zonations. Accordingly, the Tethyan calcareous nannoplankton boundary NC13/NC14 corresponds to the boreal FO of C. woolgari, the index taxon for the Lower-Middle Turonian boundary. The cyclic appearance and the temporal spacing of the small-scale carbon isotope events suggest that orbital forcing exerted control on surface water productivity and organic matter preservation at the sea floor. (c) 2006 Elsevier B.V. All rights reserved.