Basin dimensions and morphology as controls on amplification of tidal motions (the Early Miocene North Hungarian Bay)

Abstract

Following the Late Aquitanian sea‐level fall, tide‐influenced deposition started in the North Hungarian Bay, an embayment in the Paratethys open to the north‐east. The relatively narrow, funnel shape of the bay supported amplification of tidal movements, resulting in the generation of strong tidal currents. The length and the depth of the North Hungarian Bay and the connecting seaway through East Slovakia fell into the ‘Tidal Amplification Window’and thus fulfilled the conditions needed for resonant amplification of semidiurnal (M2) tides. Tide‐influenced deposits were formed at both sides of the North Hungarian Bay. They reflect dominant currents in opposite directions and of different strengths at either side of the basin. This difference was the result of bottom‐tide interactions. Cyclonic (anticlockwise) residual currents were induced above the asymmetrical central depression in the bay and were superimposed upon the tidal currents, producing an anticlockwise, time‐and‐velocity asymmetrical current system. The North Hungarian Bay and other examples show that amplification of tidal motions and formation of tide‐influenced deposits may occur if basin dimensions pass through the ‘Tidal Amplification Window’. This window represents ideal conditions for resonant or amphidromic amplification of tidal currents. It determines an ideal length/depth or width/depth ratio relative to the wavelength of the astronomical tides. Thus signs of strong tidal influence in fossil basin fills can be used to reconstruct the dimensions (length, depth and width) of such basins.

Evolution of the passive margin of the peripheral foreland basin: an example from the Lower Miocene Carpathian Foredeep (Czech Republic)

“…The Neogene tidalites within the Central Paratethys sedimentary basins are known from the Pannonian Basin (Eggenburgian) (Sztanó & de Boer 1995), the North Alpine Foreland Basin (Ottnangian) (Bieg et al 2007(Bieg et al , 2008, Kroměříž Fm.). (Zuschin et al 2014), and the Polish and Ukrainian parts of the Carpathian Foredeep (Badenian) (Lis & Wysocka 2012).…”

Calcareous nannoplankton and foraminiferal response to global Oligocene and Miocene climatic oscillations: a case study from the Western Carpathian segment of the Central Paratethys

“…High-tide markers indicate changes of basin configuration leading to high tides (Sztanó & de Boer 1995). The gradual substitution of marginal limestones by coarse clastics of the Bretka Formation is well documented and dated to 22.4-21.9 Ma by strontium isotopes (Less et al 2015) and indicates an increase in humidity.…”

Punctuated Sediment Discharge During Early Pliocene Birth of the Colorado River: Evidence from Regional Stratigraphy, Sedimentology, and Paleontology

“…Former terrestrial valleys were transformed by relative sea-level rise to a high-energy tide-dominated shallow marine embayment . The abrupt change to subtidal marl records drowning of a mixed carbonate-siliciclastic platform and/or a reduction in tidal range during a relative sea-level rise that caused the basin to pass out of the tidal amplification window (e.g., Stanzo and Boer, 1995;O'Connell, 2016).…”