Subsurface Geodynamics and Petroleum Geology of Transform Margin Basins in the Sahel of Mahdia and El Jem (Eastern Tunisia) (1)
1992; American Association of Petroleum Geologists; Volume: 76; Linguagem: Inglês
10.1306/bdff8a10-1718-11d7-8645000102c1865d
ISSN1558-9153
Autores Tópico(s)Geological formations and processes
ResumoGeophysical, structural, and seismic-stratigraphic analysis of the Mahdia sahel of Tunisia, based on seismic data and sedimentologic and microtectonic field measurements, reveals a dynamic basin formation from the Aptian to the Quaternary. Seismic-structural and isopach mapping of seismic horizons of Cretaceous and Cenozoic megasequences shows the partition of the mobile graben depocenter and carbonate and siliciclastic platform basins. These basins are limited by synsedimentary restrictions along strike-slip faults oriented east-west and north-south. The interplay of these wrench faults, in regional transtension and transpression during the Cretaceous and Cenozoic, induced the synchroneous opening and closing of the graben and platform basins, producing large accumulatio s of black shales and turbidites, and reef, oolite, and carbonate platform deposits. This was associated with the dragging, rotation, and blocking of dekakilometer-size blocks assimilated to lithospheric microplates. These movements were accompanied by volcanism and Triassic salt intrusions along the bordering active faults in the east-west-trending and north-south-trending corridors. In these basins, sequential inversion of basin subsidence and the superposition of rhombic basins and wrench depocenters created migrating depocenters and provided the conditions in rapidly subsiding areas for source rock maturation and, later, hydrocarbon migration into stratigraphic and tectonic traps. The Tunisian Sahel domain at the northern border of the African plate is characterized by tectonic mecha isms which provide a model for tectono-sedimentary basin evolution in a wrench context.
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