A facies-based depositional model for ancient and modern, tectonically–confined tidal straits
Version of Record online: 30 MAY 2013
© 2013 John Wiley & Sons Ltd
Volume 25, Issue 6, pages 446–452, December 2013
How to Cite
Terra Nova, 25, 446–452, 2013
- Issue online: 28 OCT 2013
- Version of Record online: 30 MAY 2013
- Accepted manuscript online: 14 MAY 2013 12:00AM EST
- Manuscript Accepted: 8 MAY 2013
- Manuscript Received: 14 FEB 2013
Modern and ancient tidal straits are the least well understood of all tide-dominated depositional systems. 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).
The model points out the existence of four depositional zones, laterally adjacent from the narrowest strait centre to its terminations, distributed along symmetrical or asymmetrical seaways.
These zones, whose signature is recorded in four facies associations in the Calabrian tidal straits, are as follows: (i) the strait-centre zone, associated with 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; and (iv) the strait-margin zone, where sediment massflows descend tectonically active, steep margins towards the strait axis.
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.