Senonian Cycle in the Transdanubian Central Range (dedikált példány) [antikvár]

Acta Geologicä Hungarica 26 (12), pp. 21 40 (1983) USENONIAN CYCLE IN THE TRANSDANUBIAN f'^' CENTRAL RANGEJ. Haashungarian geological institute, budapestIn the western part of the tectonic zone of the Transdauubian Central Range subsidence and transgression took place in the Senonian during which terrestrial, fresh-and brackish-water and marine carbonate platform- and basin-facies formations were produced.After presentation of the lithostratigraphic units their spatial and time relations are analyzed and then a paleogeographic model and Its variation during the geohistor-ical cycle is presented through reconstruction of the contemporaneous genetic conditions. In the light of his paleogeographical-geochronological analysis, the author calls attention to the morphological control of the sedimentary environments as evidenced by the morphology produced by the tectonic and denudation processes that preceded the transgression of the sea.Terrigenous and coal-swamp facies are associated with the depressions of deepest position which remained in a deeper position for a long time even after transgression. It is the relatively elevated karstic plateaus that become rudist-bearing carbonate platforms after being inundated by transgression. Formation thickness on the slopes between submarine rises and depressions vary at a very quick pace; slope-deposited sediments and intertonguings are conspicuous.The main features of geological history can be generalized for related cycles and these regularities may considerably enhance the prediction of mineral deposits that are often found associated with these cycles (bauxite, coal, oil and natural gas. etc.).Keywords: Stratigraphy, sedimentology, paleogeography, geohistorical cycle, Hungary, Transdanubiau Central Range, Senonian.IntroductionThe latest Cretaceous (Senonian) subsidence and the transgressions that followed in the western part of the structural zone of the Transdanubian Central Range resulted in the formation of a diversified assemblage of sedimentary rocks. The transgression process in the studied area provoked regular time-dependent changes in the environmental units which, in turn, led to changes in the character of sedimentation.Stepwise changes in environment are reflected in the lithostratigraphic subdivisions, setting natural limits to lithostratigraphic units so that these may be regarded as a kind of natural units.Address: H-1143 Budapest, Népstadion lit 14., HungaryAccepted:Ada Geologicä Hungarica 26^ 1983