"SCHLIFFFLAECHEN" (SLIDE SURFACES): A CASE FOR GRAVITY SLIDING, NOERDLINGER RIES, BAVARIA, GERMANY

At first recognized by the author as glacial striae are striated surfaces in the hilly area seen in the outer rim of the Ries Basin. Striae are radially oriented with respect to the central part of the polygonal basin form. Surfaces are most commonly parallel to bedding, however, cross-cutting surfaces are apparent as older stratified rocks have been emplaced on younger rocks (i.e., Dogger over Malm). At Holheim, the striated surfaces are flat lying: here, above and below the striated surfaces local disturbance (in situ breccia formation of hand specimen sizes (perhaps even diagenetic brecciation) with cementation and dissection along flat slide surfaces)is noted in the strata indicating that movement, when it did take place, was of a gradual nature thus interpreted as gravity sliding in the earlier phases in the history of formation of the Ries at the time of an early central uplift. At Harburg, the surfaces dip into the Ries, although Dogger overlies Malm, interpreted as subsidence during a late phase of Ries formation.