Sedimentology and Microfacies assessment of Ypresian carbonate formations in the Tellian zone (NW of Tunisia)
| dc.contributor.author | Boulvain, F. | |
| dc.coverage.spatial | Africa - Northern | |
| dc.coverage.spatial | Tunisia | |
| dc.date | 2021 | |
| dc.date.accessioned | 2024-03-14T13:25:34Z | |
| dc.date.available | 2024-03-14T13:25:34Z | |
| dc.identifier.uri | https://orfeo.belnet.be/handle/internal/12741 | |
| dc.description | The Eocene layer is known for its tectonic complexity, inherited from the MesozoicCenozoic geodynamic evolution (Bishop 1988). A structural instability affected the south Tethyan area. Specifically, the North Tunisian margin shows NE-SW topographic highs and lows (Rouvier 1977; Ben Ayed 1986; Rigane et al. 1994). The paleo-depressions were characterized by the proliferation of planktonic foraminifera (Bou Dabbous Formation source rock). Simultaneously, benthic foraminiferarich limestones were deposited on the flanks and tops of the shoals (El Garia Formation - reservoir), where nummulites are the most common, like all around the Mediterranean basin during the Eocene period. (P. F. Burollet 1956; P. Burollet 1973; Jauzein 1967; Vincent Perthuisot 1978; V Perthuisot 1981; Zargouni and Abbes 1987; Aoudjehane et al. 1992; Adil 1993; Belayouni et al. 2012). The sedimentology and sequence stratigraphy of three outcrops were studied, and extensively sampled for petrographic, mineralogical, and geochemical analysis. The study area covers the Tellian zone, NW of Tunisia. Two of the outcrops (OK and AG sections) belong to the Kasseb tectonic Unit, and the TS section belongs to the Adissa tectonic Unit. Those layers correspond to the lower Eocene succession, which is part of the Metlaoui Group (P. F. Burollet 1956). Seven microfacies (MF1- MF7), ranging from the outer to the inner ramp environment, were recognized. The distal ones correspond to Globigerina-rich mudstones and wacke- to packstones. Locally, organic matter (OK section) filled stylolites/ fissures and oil seeps on the field were observed during the sampling process. The studied outcrops sections show a progressive coarsening up, leading to the nummulites-rich pack- to grainstones microfacies, detected in the uppermost part of El Garia Formation ( MF6 - MF7 in AG section). The lithological description of the studied succession shows an alternation of massive carbonates and marly limestones. Based on lithology and thickness variation of the beds doublets and their facies and fabrics, three lithostratigraphic units were defined. The first two units recorded a transgressive sequence characterized by m to dm limestones alternating with cm-thick carbonate beds, containing planktonic foraminifera-rich facies on the top of a glauconite-rich interval (MF1, MF2, MF3, and MF4). The upper unit is characterized by nummulithoclastic packstones associated with some phosphate, glauconite grains, and radiolarians (MF5), and nummulitic packstones to grainstones (MF6, MF7). Those microfacies are interpreted as an outer ramp that corresponds to a regressive sequence. According to the previous work on the Ypresian sections in the North of Tunisia, and the current studied sections, the sedimentological correlations show a deepening up and thickening upwards in a NSW-NNE direction. | |
| dc.language | eng | |
| dc.publisher | AFRICA MUSEUM | |
| dc.title | Sedimentology and Microfacies assessment of Ypresian carbonate formations in the Tellian zone (NW of Tunisia) | |
| dc.type | Conference | |
| dc.subject.frascati | Earth and related Environmental sciences | |
| dc.audience | Scientific | |
| dc.subject.free | Geodynamics and mineral resources | |
| dc.source.title | 7 TH INTERNATIONAL GEOLOGICA BELGICA MEETING 2021 | |
| dc.source.volume | Vol.7 | |
| Orfeo.peerreviewed | No | |
| dc.identifier.doi | https://doi.org/10.20341/gbcp.vol4 | |
| dc.identifier.url | https://doi.org/10.20341/gbcp.vol4 | |
| dc.identifier.rmca | 6151 |
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