Informace o publikaci
Lower Badenian coarse-grained Gilbert deltas in the southern margin of the Western Carpathian Foredeep basin
| Autoři | |
|---|---|
| Rok publikování | 2018 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Geologica Carpathica |
| Fakulta / Pracoviště MU | |
| Citace | |
| www | http://dx.doi.org/10.1515/geoca-2018-0006 |
| Doi | http://dx.doi.org/10.1515/geoca-2018-0006 |
| Klíčová slova | coarse-grained Gilbert deltas-facies analysis-key stratal surfaces-depositional settings- provenance |
| Popis | The two coarse-grained Gilbert-type deltas in the Lower Badenian deposits along the southern margin of the Western Carpathian Foredeep (peripheral foreland basin) were newly interpreted. Facies characterizing a range of depositional processes are assigned into four facies associations - topset, forest, bottomset and offshore marine pelagic deposits. The evidence of Gilbert deltas within open marine deposits reflect the formation of a basin with relatively steep margins connected with a relative sea level fall, erosion and incision. Formation, progradation and aggradation of the thick coarse-grained Gilbert delta piles generally indicate a dramatic increase of sediment supply from the hinterland, followed by both relatively continuous sediment delivery and an increase in accommodation space. Deltaic deposition is terminated by relatively rapid and extended drowning and is explained as transgressive events.The lower Gilbert delta was significantly larger, more areally extended and reveals a more complicated stratigraphic architecture than the upper one. Its basal surface represents a sequence boundary and occurs around the Karpatian/Badenian stratigraphic limit. Two coeval deltaic branches were recognised in the lower delta with partly different stratigraphic arrangements. This different stratigraphic architecture is mostly explained by variations in the sediment delivery and/or predisposed paleotopography and paleobathymetry of the basin floor. The upper delta was recognised only in a restricted area. Its basal surface represents a sequence boundary reflecting probably a higher order cycle of a relative sea level rise and fall within Lower Badenian. Evidence of two laterally and stratigraphically separated coarse-grained Gilbert deltas declares two regional/basin wide transgressive/regressive cycles however, not necessary of the same order. Provenance analysis reveals similar sources of both deltas. Several partial source areas were identified (Mesozoic carbonates of the Northern Calcareous Alps and the Western Carpathians, crystalline rocks of the eastern margin of the Bohemian Massif, older sedimentary infill of the Carpathian Foredeep and/or the North Alpine Foreland Basin, sedimentary rocks of the Western Carpathian/Alpine Flysch Zone). |