T02 Theme 2: Shallow-marine clastics

T02-SS01 – Gateways, straits and seaways: their sedimentology and stratigraphy importance to understand basins evolution

Conveners: Olariu C. (University of Texas, USA), Rossi V. M. (National Research Council of Italy, Institute of Geosciences Georesources, Italy)

Most sedimentary basins have narrow or partial connections with other basins during at least part of their evolution, commonly during their initial “opening” and ocean flooding, or at their demise when the connection with the ocean is lost. Connections between basins can be (1) gateways, small temporary connections; (2) straits, with variable widths and depths but with strong currents created by water exchange between basins; or (3) seaways, large areas with neritic depths that connects two bathyal basins. The recently developed source-to-sink approach emphasizes that sediment source areas, transfer zones and depositional sinks are interconnected and that we need to consider their integrated evolution. However, the often disregarded gateways, straits and seaway are key to fully understand the evolution of complex sedimentary basins, which requires taking into account the links between sedimentary systems in adjacent basins. Despite the importance of gateways, straits and seaways, which are fundamental in terms of water, sediment and biotas transfer from one basin to another, and may affect their paleoecology, sedimentology and stratigraphy, there are limited studies on these basin-connection processes and deposits. To this session, we invite contributions on modern, ancient, and experimental studies of interconnected basins and their connecting gateways, straits and seaways that aim to meaningfully bridge a gap of knowledge in our current understanding of basin interaction.

T02-SS02 (new for 2021) – The waltz of processes in paralic environments – Rock record and modern perspectives

Conveners: Zuchuat V. (University of Oslo, Norway), Vaucher R. (Simon Fraser University, Canada), Gugliotta M. (University of Bremen, Germany)

Paralic depositional environments include deltas, estuaries, coastal plains, beaches, tidal flats, shelves, etc., and are commonly characterized by the interplays of various processes (e.g. riverine, tidal, waves, wind). These mixed-process hydrodynamics result in mixed sedimentary facies and complex morphodynamics and stratigraphic architectures. These aspects are difficult to decipher, especially if considering that these depositional systems are prone to change through geological time because of variations in relative sea levels, climate and sediment supply, among others.

These particular transition zones affect our global appreciation of the system while interpreting the rock record. For example, where does the river end, and where does the estuary start? What is happening across this transition zone? How do arid coastal plains intertongue with seas? How to correlate coeval deposition of transgressive and regressive packages?

Further, transition zones do not only exist between environments, but they also occur on a temporal scale: how do the paralic environments evolve if the climate shifts towards more humid, more arid, or more seasonal conditions?

In this session, we invite everyone who works in paralic systems either in the rock record or in modern settings, with data acquired (but not limited to) from fieldwork, remote-sensing, experimental lab work, and numerical modelling. Researchers dealing with transitional zones sensu lato are warmly welcome to showcase their work, and we specifically encourage Early Career Scientists to give oral presentations.