A facies‐based depositional model for ancient and modern, tectonically–confined tidal straits

Abstract

Modern and ancient tidal straits are the least well understood of all tide-dominated depositional systems. In order to provide an increased understanding of these systems, a facies-based depositional model is assessed by comparing multibeam surveys of three present-day tidally-dominated seaways with a number of superbly exposed Neogene-to-Quaternary strait-fill successions of Calabria (south Italy).\ud \ud The model points out the existence of four depositional zones, laterally-adjacent from the narrowest strait center to its terminations, distributed along symmetrical or asymmetrical seaways.\ud \ud These zones, whose signature is recorded in four facies associations in the Calabrian tidal straits, are: (i) the strait-center zone, associated to the tidal current maxima and where sediments are scarce or absent; (ii) the dune-bedded zone, where sediments form dune complexes due to tidal flow expansion; (iii) the strait-end zone, where currents decelerate accumulating thinly-bedded, fine-grained deposits; (iv) the strait-margin zone, where sediment massflows descend tectonically-active, steep margins towards the strait axis.\ud \ud In ancient, tectonically-confined, narrow seaways, these facies generate a distinctive deepening-upward vertical succession, where tidal currents are the dominant process in the sediment distribution

Three‐dimensional to two‐dimensional cross‐strata transition in the lower Pleistocene Catanzaro tidal strait transgressive succession (southern Italy)

“…Other similar examples occur in the Calabrian Arc itself where, during the Neogene to Quaternary, comparable tectonic settings produced narrow‐linear basins, along which tidal currents, equivalent to those that dominated the Catanzaro strait‐fill deposits, accumulated large tidal dunes in the Tortonian Mt Pellegrino Strait, Amantea Basin and the Pleistocene Siderno Palaeostrait (Fig. ) (Colella & D'Alessandro, ; Longhitano & Nemec, ; Longhitano, , ; Longhitano et al ., ). All of these ancient examples of large dunes filling tidally dominated straits show analogous depositional architectures and facies assemblages of the cross‐strata complexes (Longhitano et al ., ).…”

“…Schematic representation of the main Neogene to Quaternary, tectonically controlled tidal seaways of Calabria linking the Tyrrhenian and the Ionian basins (modified from Longhitano, ). These straits generated continuous exchanges of marine waters between the two basins, regulated by semi‐diurnal tidal inversions.…”

“…A) favoured the opening of several narrow, linear basins (Ghisetti & Vezzani, ; Turco et al ., ; van Dijk et al ., ; Monaco & Tortorici, ; Bonardi et al ., ; Tansi et al ., ; Tripodi et al ., ). Most of these basins acted as tidally dominated seaways during the middle Miocene to early Pleistocene (Longhitano, , ; Longhitano et al ., ), including the Amantea, Catanzaro, Siderno and Messina areas (Fig. B).…”

Deformed cross-stratified deposits in the Early Pleistocene tidally-dominated Catanzaro strait-fill succession, Calabrian Arc (Southern Italy): Triggering mechanisms and environmental significance

“…A tidal origin for these deposits has been extensively documented by several papers, and it is indicated by bimodal palaeocurrent pattern (i.e. herringbone cross-stratification), reactivation surfaces and tidal rhythmites composed of mixed siliciclastic-bioclastic couplets (Chiarella, 2011;Longhitano, 2011;Chiarella et al, 2012a;Longhitano et al, 2012;Longhitano, 2013;Longhitano et al, 2014).…”

Sedimentation in a synclinal shallow‐marine embayment: Coniacian of the North Sudetic Synclinorium, SW Poland

“…The hypothetical strait is estimated to have been three to four-times narrower than the North Sudetic Basin itself (cf. Longhitano, 2013). Its existence is evidenced by the localized accumulation of Figure 1B and Table 1 multiple, northwest-advancing tidal sand ridges in the southeastern head-part of the basin (cf.…”