The detailed sedimentological study of the 150-m-thick Muschelkalk succession, deposited on a small (~200 by 80 km), morphologically diverse Upper Silesian carbonate platform during four major marine-transgressive pulses of the Tethys Ocean, enhanced the understanding of the depositional history, palaeogeography, and facies distribution. A total of thirty-five lithofacies types were identified, described and interpreted in terms of depositional settings. These different lithofacies represent various shallow-marine environments along the platform transect, from peritidal to offshore areas. The vertical and lateral organization of the lithofacies delineated was caused by the interplay of platform morphology, third-order eustasy and the long-term tectonic evolution of the area. Accordingly, the carbonate system studied is a good example of the influence of large-scale processes on the facies architecture of carbonate platforms. In general, all of the four Transgressive Systems Tracts are characterized by similarity in lithofacies composition and vertical succession and by minor lateral change, indicating only limited influence of the three large-scale factors mentioned on lithofacies development and distribution during transgressions. In contrast, each of the four associated Highstand Systems Tracts comprises an individual (unique) lithofacies assemblage displaying substantial regional and local variation, which indicates that the filling of accommodation space during highstands strongly depended on the extrinsic processes.
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W pracy przedstawiono wyniki badań śródmenilitowych piaskowców magdaleńskich, które występują w jednostce śląskiej w obrębie tzw. fałdu Gorlic w Karpatach Zewnętrznych. Były one dotychczas interpretowane jako utwory prądów zawiesinowych (turbidytów) powstałych w głębokowodnym, batialnym zbiorniku sedymentacyjnym. Szereg zinterpretowanych struktur sedymentacyjnych oraz rekonstrukcja systemu depozycyjnego wskazuje jednak na ich płytkowodną, deltową, zdominowaną procesami falowymi i pływowymi genezę. Utwory te powstały w strefie aktywnego, kontrolowanego procesami tektonicznymi szelfu. Pełna sukcesja warstw menilitowych i piaskowców magdaleńskich jest interpretowana, jako sekwencja depozycyjna z rozwiniętymi w jej obrębie traktami: niskiego stanu, transgresywnym i wysokiego stanu względnego poziomu morza.
EN
Recent sedimentological studies of the Menilite Beds in the Gorlice area suggest a shallow-marine origin of this succession, including the Magdalena Sandstone. The occurrence of features interpreted as wave-ripple cross-lamination and hummocky stratification implies deposition above the storm wave base, which means a water depth, of perhaps less than 50 m on the account of the landlocked nature of the narrow Carpathian Paratethys seaway. The Menilite Beds with Magdalena Sandstone deposits form a 180-m thick succession comprising three coarsening-upwards regressive parasequences. The basal shales of the succession contain sandstone bodies interpreted to be shelf-margin channels or gullies filled by debris flows and high-density turbidity currents, and considered to be a signal of an impending forced regression driven by tectonic uplift. Each of the overlying parasequences commences with heterolithic deposits dominated by black to grey shales and showing lenticular, wavy or flaser bedding as well as graded beds with plane-parallel or hummocky stratification and wave-ripple cross-lamination, interpreted to be outer-shelf tidalites and distal tempestites. The thicker sandstone beds in parasequence middle part, with parallel and apparent hummocky stratification as well as wave-ripple cross-lamination, are considered to be sublittoral prodelta tempestites. The upper part of each parasequence is dominated by coarse-grained quartz-glauconite sandstones and quartz-rich pebble conglomerates, which form broadly convex-upwards packages stacked in an offset ‘compensational’ manner, interpreted to be shingled distal to proximal mouth bars of an advancing shoal-water deltaic system. Sedimentation is thought to have occurred on a tectonically-steepened perched narrow shelf, where the accommodation-driven deltaic system was readily reaching the shelf margin. Marine flooding events are attributed to the shelf episodic foundering. The ultimate collapse of the shelf then brought turbiditic sedimentation represented by the overlying succession of late Oligocene–Miocene Krosno Beds. The Menilite Beds with Magdalena Sandstone are interpreted as a depositional sequence with lowstand (first parasequence), transgressive (second and third parasequences) and highstand systems tracts.
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