A　variety　of　soft-sediment　deformation　structures　(SSDSs)　were　identified　in　the　Late　Cretaceous　Wangshi　Group,　which　is　situated　in　the　South　Malingshan　Hill　in　the　southern　segment　of　the　Tan-Lu　Fault　Zone　(TLFZ),　eastern　China.　The　SSDSs　mainly　formed　in　the　piedmont-diluvial,　alluvial,　and　lacustrine　stratum　in　the　GaoshanTancheng　graben　basin　bounded　by　the　normal　fault　systems　within　the　TLFZ.　In　this　study,　the　morphological　features　and　formation　mechanisms　of　SSDSs　have　been　investigated,　and　potential　linkage　between　the　formation　of　SSDSs　and　regional　tectonic　activities　has　been　inferred.　The　results　showed　that　the　types　of　SSDSs　observed　in　this　area　consist　of　the　liquefied　sand　veins,　liquefied　sand　dykes,　liquefied　breccias,　diapirs,　convolute　laminations,　soft　boudinage　structures,　load　and　flame　structures,　ball-and-pillow　structures,　seismic　folds,　seismic　slumps,　syn-sedimentary　faults,　seismic　fissure　fillings　and　flowing　structures　of　thixotropic　soft　clay.　The　analysis　of　SSDSs　reveals　that　their　deformation　mechanisms　can　be　attributed　to　the　liquefaction,　fluidization,　thixotropy,　plastic　and　brittle　deformations　within　sandy,　silty,　and　clay　alternating　stratigraphic　systems,　driven　by　gravitational　instabilities　due　to　reversed　density　gradients,　uneven　loading,　slope-related　gravitational　forces,　and　shear　and　lateral　stresses.　Considering　the　characteristics　of　SSDSs　and　geological　setting,　seismic　events　and　fault　activities　are　proposed　as　the　most　plausible　triggers　for　SSDSs,　indicating　that　at　least　19　seismic　events　of　magnitude　M　＞=　5　have　occurred　in　the　Late　Cretaceous　period.　The　study　also　provided　significant　insight　into　the　declining　trend　in　tectonic　and　seismic　activities　during　the　Late　Cretaceous　period　in　this　region.