Geochemical Characterisation and Correlation of Cenomanian Turonian Sediments in Central-eastern Tunisia

Earth and environmental sciences

“…Our results confirm the relationship occurrence between stratigraphic sequence sytems tract and Sr/Ca evolution as described at Culver (Murphy, 1998;Mabrouk et al, 2006) and elsewhere in Gubbio (Stoll and Schrag, 2001). The Culver Sr/Ca profile was may be compared with that of Gubbio (Italy) and Bargou (Tunisia) inspite that these three sections cannot be easily correlated biostratigraphically in detail since the biomarker among macrofossils and foraminifera are rare even absent at both Italian (Gubbio) and Tunisian (Bargou) sections seeing their siliceous facies frequency.…”

“…The Sr/Ca ratio values generally fall through TST (mean value ~40) and remain relatively constant through the lower part of the Bahloul Formation, then show a significant decrease to much lower Sr/Ca values for reaching minimum values in the upper part of it (~20) close to the MFS at the top of the formation (Figure 3; Figure 5). This feature is conforming to that described by Mabrouk et al (2006) in Bahloul Formation from Tunisian onshore and elsewhere.…”

“…Major elements concentrations (Figure 3) were determined using Mass spectrometry (ICP-AES) process and trace elements were determined using Induced Coupled Plasma Mass Spectroscopy (ICP-MS) at ETAP. In this study Sr/Ca and Mn variation curves were determined to check relationships with sea level flucruation as described by Mabrouk et al (2006). Thin sections were made in the hard limestone samples in order to analyze microfacies in the laboratory of sedimentology of the "Office National des Mines".…”

“…This is may be due to the Mn supply that was coupled with the biogenic flux (e.g. organic carbon), which must have decreased during the SMW (Murphy, 1998;Stoll and Schrag, 2001;Mabrouk et al 2006;Soua, 2010b). Mn profile increased with rising sea-level, reaching a maximum around each MFS (Figure 3b), before decreasing again through the overlying HST, representing a period of relative constant carbonate supply.…”

“…In fact using Sr/Ca profiles, ratios maxima identified within this interval transition at Culver (England) and at Gubbio (Italy) are also identifiable at Bargou (Tunisia). Mabrouk et al (2006) mentioned that breaks within the Sr/Ca curves may indicate sedimentological or diagenetic effect. At the Bargou section these breaks may correspond to intervals of silica-rich black shales comparable to the Livello Bonarelli.…”