A zsámbéki Strázsa-hegy és környékének kainozoos képződményei
| Autor: | Balázs Musitz, Zoltán Lantos, Andrea Szurominé Korecz, Tamás Budai, Zsolt Kercsmár, Ildikó Selmeczi |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Földtani Közlöny. 150:129 |
| ISSN: | 2559-902X 0015-542X |
| Popis: | In the course of the geological mapping in the Zsambek Basin, the Cenozoic succession – exposed in the quarry of the Strazsa Hill – was accurately documented. Moreover, analyses of palaeontological, stratigraphic and tectonic data were also conducted. The Middle Triassic dolomite is overlain by a relatively thin middle–upper Miocene succession of discontinuous appearance; its lower section is made up of fine-grained siliciclastic deposits (silt–medium grained sand) and carbonates of late Badenian (late Langhian–early Serravallian) age. The freshwater limestone, unconformably overlying the latter, is considered as the basal formation of the upper Miocene (Pannonian) succession of the Zsambek Basin. The Pannonian succession characterised by considerable thickness and areal extent in the Zsambek Basin is missing due to denudation, and the algae-bearing freshwater limestone is directly overlain by an alluvial–proluvial succession of Pleistocene age. Based on the analysis of sedimentological characteristics and the study of fossils the Neogene sedimentary environment shows particular features in many respects. At the beginning of the late Badenian sedimentation took place in a protected, coastal, lower salinity lagoon behind the palaeomorphologic ridge (island or peninsula) located along the Vertessomlo–Nagykovacsi Zone. The lagoon received a large amount of sediment influx of fine-grained clastic deposits. Simultaneously, on the southern side of the island a rocky shore (characterised by abrasion) could be reconstructed. We detected freshwater influx during the late Badenian. In the Sarmatian it became restricted and at the beginning of the late Miocene a lacustrine environment came into being. During the Neogene–Quaternary structural evolution of the Vertessomlo–Nagykovacsi Zone of W–E strike, several phases could have been identified. The earliest one among them is the small-scale thrusting of the Triassic dolomite over the middle Miocene succession, which can be coeval with the deposition of the late Badenian siliciclastic succession. The activity of the tectonic zone in the Sarmatian is indicated by the extremely thin occurrence and unconformable setting of the succession. The next structural phase is indicated by lateral striae observed on the Pannonian freshwater limestone; this phase corresponds to D11 transpressional deformation phase identified in the Gerecse. Uplift occurring in the course of the youngest deformation process of the tectonic zone resulted in the denudation of the Pannonian succession. This process may have been taken place during the Pliocene–early Pleistocene. |
| Databáze: | OpenAIRE |
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