Late quaternary sea level changes of Gabes coastal plain and shelf: Identification of the MIS 5c and MIS 5a onshore highstands, southern Mediterranean

Abstract

The continental shelf of the Gulf of Gabes is outlined, during the MIS 5c and MIS 5a onshore highstands, by the genesis of forced regressive beach ridges situated respectively at-19 m b.s.l/100 ka and-8 m b.s.l/80 ka. This area, considered as a stable domain since at least the last 130 ka (Bouaziz et al. 2003), is a particular zone for the reconstruction of the late quaternary sea-level changes in the region. Shuttle Radar Topography Mission (SRTM) data and field observations are highlighted to deduce interaction between hydrodynamic factors and antecedent topography. Variations in geomorphology were attributed to geological inheritance. Petrography and sedimentary facies of the submerged coastal ridges reveal that the palaeocoastal morphology was more agitated than today and the fluvial discharges are consistent. Actual morphologic trend deduced from different environment coasts (sandy coasts, sea cliffs and tidal flat) is marked by accumulation of marine sands and progradation. Keywords. MIS 5c and MIS 5a; beach ridges; sea level changes; palaeocoastal morphology; Gulf of Gabes; Tunisia.

A review of last interglacial sea-level proxies in the eastern Mediterranean coastal region

“…Gzam et al 2016) but also unusual shore-parallel hyrodynamic conditions (Sammari et al, 2006;Gzam et al 2016). The LIG deposit is part of a beach ridge stretching parallel to the modern coastline at ca 3 m altitude (Gzam et al, 2016).…”

MIS 5e sea-level proxies in the eastern Mediterranean coastal region

“…Gulf of Gabès (Tunisia) -the gulf is part of the collapsed Jeffara block dominated by normal faulting during the Quaternary (Gharbi et al, 2016). Shape and geometry of the gulf funnels the tidal wave with the consequence that the gulf coast experiences not only the highest tidal range in the Mediterranean (1.5 m; Gzam et al 2016) but also unusual shore-parallel hyrodynamic conditions (Gzam et al 2016). The LIG deposit is part of a beach ridge stretching parallel to the modern coastline at ca 3 m altitude (Fig.…”

“…For the selected zones we assume coastal geometries, hence tidal prism, to be similar to today because the course of the LIG beach ridges and barriers suggest a LIG coastline running sub-parallel to the modern one. The mean tidal range today is 0.5 m (Admiralty Tide tables) apart from the Gulf of Gabès (1.5 m; Gzam et al, 2016).…”

“…4) -The LIG deposit is part of a coastline-parallel beach ridge. The lower part of the ridge is characterised by planar laminated beds of bioclastic sand bearing Strombus bubonius fossil remains (Gzam et al, 2016). The deposit is situated at 3 m (Gzam et al, 2016).…”

“…The lower part of the ridge is characterised by planar laminated beds of bioclastic sand bearing Strombus bubonius fossil remains (Gzam et al, 2016). The deposit is situated at 3 m (Gzam et al, 2016). This is a facies-based sea-level indicator with an indicative range of +3 m to 0 m including 1.5 m mean tidal range.…”