Sedimentology of Ancient Coastal Wetlands: Insights From A Cretaceous Multifaceted Depositional System

Abstract

Coastal wetlands are prominent modern environments widely studied in geomorphology and ecology, but the term ''coastal wetland'' is still barely used for the sedimentological classification of ancient deposits. The depositional system studied here (Leza Formation, Cameros Basin, Early Cretaceous, N Spain) includes diverse carbonate and clastic facies deposited at the sea-land transition, and is an illustrative example of the wide array of sedimentary environments that may occur in coastal wetlands systems. The studied system was composed mainly of carbonate water bodies whose salinity ranged from fresh to brackish and near-marine, and which had variable input of clastic material due to their lateral connection with alluvial fans. In addition, the system also included carbonate water bodies with stronger marine influence, tide-influenced oolitic areas, and relatively restricted evaporative settings.

Revisiting the Late Jurassic-Early Cretaceous of the NW South Iberian Basin: new ages and sedimentary environments

“…Wilkinson and Drummond, 2004;Suarez-Gonzalez et al, 2015), as it has been reported in numerous modern systems, such as Bahamas (e.g. Bathurst, 1975;Reijmer et al, 2009;Kaczmareck et al, 2010;Harris et al, 2015), Persian Gulf (e.g.…”

“…All these features suggest that sedimentation of the Aldea de Cortés Fm took place in a "coastal wetland" (sensu Suarez-Gonzalez et al, 2015), because it includes numerous sedimentological features that characterize this type of depositional system: shallow-water facies containing both continental and marine fossils, common subaerial exposure, edaphic features, and complex distribution of interbedded continental, transitional, and marine deposits. Mas (1981), Mas and Alonso (1981), and Mas et al (1982) and interpreted the unit, in the study area, as deposited in a lagoon surrounded by a tidal flat environment which, in turn, was surrounded by a fluvial deltaic plain.…”

The Middle Jurassic Alpine Tethyan Unconformity and the Eastern Sardinia - Corsica Jurassic High: A sedimentary and regional analysis

“…Finally, the topmost lithofacies is 3) the Usassai-Perdadefogu lithofacies, which alternates carbonates and fine-to middle-grained siliciclastics locally with coal seams. This is typical of a deltaic-mixed lagoon environment ("coastal wetlands" sensu Suárez-González et al, 2015), and suggests the gradual passage to the carbonate shelf of the upper Dorgali Fm (Costamagna and Barca, 2004;Costamagna, , 2015 (Fig. 2).…”

A palaeoenvironmental reconstruction of the Middle Jurassic of Sardinia (Italy) based on integrated palaeobotanical, palynological and lithofacies data assessment

“…It documents the formation of a main tectonic high later fragmented into several minor highs and culminates with their final transgression. A narrow continental to transitional shallow marine depositional system was formed along the slopes of the tectonic highs (coastal wetland sensu Suárez-González et al 2015). The high-gradient palaeoslopes eroded filling the marginal depositional environments.…”