ALBERT

Description: A detailed sequence stratigraphic study of the Cenomanian–Turonian strata of the Elbtal Group focussing on new core and outcrop data provided important clues for the understanding of early Late Cretaceous sea-level changes in the Saxonian Cretaceous Basin. Depositional sequence-bounding unconformities have been dated using high-resolution macrofossil biostratigraphy, relying on newly obtained and previously published data, and correlated between individual sections. In the Middle Cenomanian–Late Turonian, seven sequence boundaries (SB Ce 4 and 5, SB Tu 1–5) have been identified that define seven 3-order depositional sequences (DS Ce 4 and 5, DS Ce–Tu 1, DS Tu 2–5). Sequences DS Ce 4 and DS Ce 5 are capped by unconformities SB Ce 4 and SB Ce 5 (latest Middle and mid-Late Cenomanian in age). Their deposition was strongly influenced by pre-transgression palaeo-topography; they can be completely missing on basement highs. DS Ce–Tu 1 (mid-Upper Cenomanian–Early Turonian) started with the major Transgression and onlap continued with a second pulse into the earliest Turonian, finally levelling the pre-existing topography and giving rise to more uniform sedimentation patterns of a graded shelf system during the Turonian. The next sequence boundary is SB Tu 1, a conspicuous unconformity within the Lower–Middle Turonian boundary interval. DS Tu 2 has an early Middle Turonian age. The up-section following sequence DS Tu 3 is of late Middle–earliest Late Turonian age and was characterised by a significant rise in sea-level terminated by a forced regression in the earliest Late Turonian (SB Tu 3, abrupt basinward shift into coarse-grained sandstone facies). Renewed sea-level rise during the early to mid-Late Turonian within DS Tu 4 is documented by a fining trend. A rapid coarsening in grain size in response to strong forced regression resulted in the formation of SB Tu 4 (mid-Late Turonian) and basinward progradation of thick-bedded sandstones in the lower part of DS Tu 5, followed by a major mid-Upper Turonian transgression culminating in a maximum flooding interval equating the Event. Highstand shallowing ended at the late Late Turonian unconformity SB Tu 5. The sequence stratigraphic subdivision of the Elbtal Group compares well to the results of earlier studies and can be translated into the genetic sequence stratigraphy developed for the Bohemian Cretaceous Basin.