Geochemical characterization of upper Berriasian to lower Turonian lithostratigraphic units from the Hanover area

In northern Germany, Lower Cretaceous sediments are predominantly represented by CaCO₃-poor mud- and siltstones of up to 2000 m thickness, which become more carbonate-rich during the Albian-Cenomanian transition and even chalkier in the upper Cenomanian. The sedimentary system can be simplified considered as bimodally controlled by carbonate and fine-grained siliciclastics; in addition, some lithostratigraphic units are characterized by a high organic carbon content (Hoheneggelsen Formation, Barremian-Lower Aptian; Hesseltal Formation, Cenomanian-Turonian).
We present a 1500-m-thick composite record of late Berriasian to middle Turonian age based on 14 drill cores and about 4500 samples. All cores and successions are located in the larger Hanover area, which represents the depocenter of the North German Lower Saxony Basin in early to mid-Cretaceous times. Beside a recently published long-term carbon-isotope stratigraphy, we generated high-resolution calcium carbonate and organic carbon data, which nicely trace the lithostratigraphic units on formation and on member level, allowing for a more detailed characterization for most of the units. Only the Albian-Cenomanian transition from the Peine to the Herbram Formation is less well developed in the geochemical data.