Tidal sediments in the Upper Marine Molasse (OMM) of the Allgau area (Lower Miocene, Southwest-Germany)

Frieling, Dorothea; Mazumder, Rajat; Reichenbacher, Bettina


Evidence for tidal influences in the Upper Marine Molasse (OMM) of the Allgäu area (Southwest German part of the Molasse Basin) is presented. The studied sections in the "Ellhofer Tobel" ravine reveal an approximately 140 m thick succession of marine sediments. Four different facies types are distinguished in this succession: 1) a Glauconitic Sandstone Facies, 2) a Heterolithic Facies, 3) a Cross-Stratified Sandstone Facies and 4) a Conglomeratic Facies. These lithofacies represent different near coastal and shallow marine environments. A tidal influence is indicated by the presence of the Heterolithic Facies which contains associated epsilon cross-stratification and megaripples (or subaquatic dunes). A general current direction from south to north is consistent documented by subaquatic dune foresets and the orientation of ripple foresets. If the coastal environment near the southern coast of the Molasse Sea had a rather simple tidal current regime this dominant northerly current direction could be interpreted as ebb currents.


early miocenemolasse basinallgauupper marine molasse (omm)tidal sediments