The mid-Tournaisian Event in the Hörre Nappe — conodont fauna and sequence stratigraphy from the Gladenbach section (Gladenbach Formation, eastern Rhenish Massif)

The Gladenbach section, type section of the Gladenbach Formation, is one of the rare sections that allow an insight into the Tournaisian succession of the Southern Rhenohercynian Zone. Due to its position within the allochthonous Hörre Nappe, deriving from the Armorican Terrane Assemblage south of the Rhenish Massif, the Gladenbach Fm differs from time-equiva-lent siliceous accumulations (Kahlenberg Fm and lower part of the Hardt Fm) within the Kulm Basin. In contrast to most other sections in the Rhenish Massif, the limestone beds of the Gladenbach Fm offer a unique and rare possibility to study microfossils from the “middle” Tournaisian. The rich conodont fauna of the Gladenbach section allows the recognition of the Lower crenulata, isosticha-Upper crenulata and Lower typicus zones and the assignment to the Siphonodellid-Polygnathid Biofacies (lower slope and basin) of the Gladenbach Fm. The limestones are intercalated by dark shales and can be grouped into many turbiditic fining-upward cycles that allow the assignment to one complete and a second partly documented 3^rd order sequence already recognised in the Kulm Basin and adjacent platform areas in the Belgian Ardennes.

The here presented findings, as well as the results from other studies, validate the assumption that the Gladenbach Fm represents accumulations of deep basins or deep distal slope areas that in part were fed by calciturbidites deriving from deeper water and lower, middle and upper slope deposits.