From non‐tidal shelf to tide‐dominated strait: The Miocene Bonifacio Basin, Southern Corsica

Abstract

International audienceThis study documents a change from a non-tidal to tide-dominated shelf system that occurred between Corsica and Sardinia (the Bonifacio Basin, Western Mediterranean) during the early to middle Miocene. The non-tidal deposits formed on a low-energy siliciclastic shelf surrounded by progradational coralline algal ramps at full highstand. The tidal deposits consist of an up to 200 m thick succession of siliciclastic to coralline-rich cross-beds formed by large sub-tidal dunes. Based on outcrop and sub-surface data, it is possible to conclude that the tidal currents were amplified as a consequence of the rapid subsidence of the basin centre due to tectonic activity. It is suggested that this tectonic event initiated the strait between Corsica and Sardinia. The strait was deep enough to allow the tidal flux to be significantly increased, generating a localized strong tidal current at the junction between the Western Mediterranean and the East Corsica Basin

Residence time, mineralization processes and groundwater origin within a carbonate coastal aquifer with a thick unsaturated zone

“…shelly litharenites, a sandy silt level (materializing the separation between the upper and lower aquifer) and coralline-rich calcarenites (Reynaud et al, 2012). This formation was also fed by abundant near shore siliciclastic sediments (Tomassetti et al, 2012).…”

“…Many lens filled of gravel material are present. Well-cemented limestone completes the series (Reynaud et al, 2012). …”

“…Fig 1: Map of the general geology (simplified from Reynaud et al, 2012), topography and distribution of sampling points. The green symbols are for the boreholes and wells pumping in the upper aquifer.…”

“…Several stratigraphic logs were defined in the area (Ferrandini et al, 2003;Orsini et al, 2010;Reynaud et al, 2012), showing three major sedimentary formations with little differences in the deposit sequences. In this paper, we refer to the stratigraphic log of Reynaud et al (2012).…”

An Analytical Method for Assessing Recharge Using Groundwater Travel Time in Dupuit‐Forchheimer Aquifers

“…The Bonifacio aquifer located in the southern part of the island of Corsica (France) was selected for the field study illustration because its geology and hydrogeological features are well documented (Orsini et al ; Reynaud et al ; Santoni ; Santoni et al ). Previous studies have made it possible to accurately assess its groundwater residence times using hydrochemistry, anthropogenic atmospheric gases (chlorofluorocarbons [CFCs] and sulfur hexafluoride [SF 6 ]) and strontium isotopes (Santoni et al , ).…”