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Numerical tidal modelling, when integrated with other geological datasets, can significantly inform the analysis of physical sedimentation processes and the depositional and preservational record of ancient tide‐influenced shoreline–shelf systems. This is illustrated in the Oligo–Miocene of the South China Sea, which experienced significant changes in basin physiography and where tide‐influenced, shoreline–shelf deposition is preserved in ca 10 sub‐basins. Palaeogeographic reconstructions, palaeotidal modelling and regional sedimentary facies analysis have been integrated in order to evaluate the spatial–temporal evolution and physiographic controls on tidal sedimentation and preservation during the ca 25 Myr Oligo–Miocene record in the South China Sea. Palaeotidal modelling, using an astronomically‐forced and global tidal model (Fluidity) at a maximum 10 km resolution, indicates that spring tides along Late Oligocene to Middle Miocene coastlines were predominantly mesotidal–macrotidal and capable of transporting sand, which reflects two main conditions: (i) increased tidal inflow through wider ocean connections to the Pacific Ocean; and (ii) tidal amplification resulting from constriction of the tidal wave in a 'blind gulf' type of basin morphology. Since the Middle to Late Miocene, a reduction in the amplitude and strength of tides in the South China Sea was mainly due to diminishing tidal inflow from the Pacific Ocean caused by the northward movement of the Philippines and Izu–Bonin–Mariana arc. Sensitivity tests to palaeogeographic and palaeobathymetric uncertainty indicate that regional‐scale (hundreds to thousands of kilometres) palaeogeographic changes influencing tidal inflow versus outflow can override local‐scale (one to hundreds of kilometres) changes to tidal resonance and convergence effects (funnelling and shoaling), such as shelf width and shoreline geometry. Palaeotidal model results compare favourably to the distribution and sedimentary fabric of Oligo–Miocene, tide‐influenced, shoreline–shelf successions in peripheral South China Sea basins. However, the preservation potential of tidal deposits is lower in open coastline environments, probably due to enhanced reworking during storms and river floods. [ABSTRACT FROM AUTHOR]

Quattrocchi, A.; Gorman, J.G., Piggott M.D. and Cucco, A., 2016. M2, overtides and compound tides generation in the Strait of Messina: the response of a non-hydrostatic, finite-element ocean model. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 657-661. Coconut Creek (Florida), ISSN 0749-0208. The nonlinear interactions between the main tidal constituents and geographical constraints are investigated using Fluidity-ICOM, a non-hydrostatic finite-element ocean model that was implemented in the region of the Strait of Messina (Mediterranean Sea). As a first crucial approach, the barotropic tidal dynamics was investigated and the model solution was interpreted in terms of tidal maps and spectra obtained by harmonic analysis of the sea surface elevation. The model domain is represented by an unstructured mesh with variable spatial resolution ranging from two kilometres to fifty meters, in order to resolve the shoreline in the inner part of the Strait. Amplitudes and phases of the main diurnal and semidiurnal tides were prescribed at the off-shore open boundaries. A calibration procedure was carried out with available observations in order to provide a suitable parameterization for bottom drag coefficient and horizontal viscosities. The results gave clear indication that over-harmonics and compound tides are generated in the Strait. The generation mechanism, geographical localization and intensity of these phenomena were described to provide groundwork for further model analyses that would clarify the role of shallow water tides in modifying the hydrological setup in proximity of sea straits. [ABSTRACT FROM AUTHOR]

Due to a lack of modern analogues, debate surrounds the importance of tides in ancient epi-continental seas. However, numerical modelling can provide a quantitative means of investigating palaeo-tidality without recourse to analogues. Finite element modelling of the European Upper Carboniferous epi-continental seaway predicts an exceedingly low Lunar tidal range ( ca 5 cm in the open water regions of the UK and Southern North Sea). The Imperial College Ocean Model (ICOM) uses finite element methods and an unstructured tetrahedral mesh that is computationally very efficient. The accuracy and sensitivity of ICOM tidal range predictions were tested using bathymetric data from the present-day Mediterranean Sea. The Mediterranean Sea is micro-tidal and varies in depth up to 5·4 km with an average depth of 1–2 km. ICOM accurately predicts the tidal range given both a realistic, but smoothed, bathymetry and a straight sided basin with a uniform depth of 1 km. Variation in uniform depth from 100 to 3000 m with and without islands consistently predicts micro-tidality, demonstrating that the model is robust and the effect of bathymetric uncertainty on model output is relatively small. The extremely low tidal range predicted for the European Upper Carboniferous is thus deemed robust. Putative Upper Carboniferous tidal deposits have been described in the UK and southern North Sea, but are represented by cyclic rhythmites and are limited to palaeo-estuaries. Calculations based on an embayed coast model show that the tidal range could have been amplified to ca 1 m in estuaries and that this is sufficient to form cyclic rhythmites. Without tidal mixing, the tropical equatorial heat and salinity enhancement would promote stratification in the open water body. The introduction of organic matter probably caused anoxia, biotic mortality and carbon accumulation, as evidenced by numerous black ‘marine-band’ shales. [ABSTRACT FROM AUTHOR]