Quaternary tectonics and seismic stratigraphy of the western Black Sea shelf

Zusammenfassung

Interpretation of high and very high resolution reflection seismic data from the western Black Sea shelf yielded a seismic stratigraphic model of the Late Quaternary deposits on the southwestern Black Sea shelf. This model was combined with borehole information to carry out a regional subsidence analysis, so that the influence of tectonics and sediment compaction could be ruled out in the estimation of sea-level changes in the Black Sea. Mio-Pliocene sediments form the baseline of the interpretation. On top of it four Quaternary seismic stratigraphic units were identified on the western Black Sea shelf; they are named in chronological order Unit 4 to Unit 1 (U4 U1). Pliocene deposits are built up by gently basinward dipping layers of relatively high and approximately uniform thickness. Buried graben structures attest to the influence of extensional tectonics until the Upper Pliocene. Later, strong erosion left a rugged surface on the inner and middle shelf that was later overlain by a thin layer of Quaternary to Holocene sediments. The Pliocene is followed by the oldest observed Quaternary seismic sequence (Unit 4, U4); it comprises layers of Lower Quaternary age that dip towards the basin at a steeper angle than those of the Pliocene. Within U4 the oldest of three Quaternary shelfedge delta systems in the study area was found, that supposedly marks an Early Quaternary sea-level lowstand...
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