Research in Tunisia

This study was undertaken by Stefan Lubeseder, supervised by Prof Jonathan Redfern. The aim was to develop a third-order sequence stratigraphic framework for the Silurian and Devonianof North Africa, focusing on Morocco, Algeria, Tunisia and Libya. Due to the stability of the Saharan Craton during this period, Palaeozoic stratigraphy is relatively uniform across the area, allowing a regional study. Palaeozoic rocks form important reservoir and source rocks in North Africa, from the Cambrian to the Carboniferous. A sequence stratigraphic scheme together with the geometry of depositional systems and the key characteristics of their boundaries was developed, which offers as a valuable tool for the prediction of reservoir units in areas beyond data control. The outcrop studies can also serve as analogues to reservoir units in the subsurface. The final PhD thesis contain large inter-regional chronostratigraphic correlation charts, constructed to illustrate the intracratonic depositional model for North Africa.

Practically, the study was split into three parts:

Morocco field case study

Silurian: Silurian sections were studied in the Tafilalt area as well as in the Dra Plain of southern Morocco (Anti-Atlas). The emphasis was on the Ludlowian "Orthoceras" limestones and the so-called "Scyphocrinites" limestones at the Silurian/Devonian boundary. These limestone levels were studied in terms of their biostratigraphic position, depositional system, and inter-regional sequence stratigraphic significance. Silurian "Orthoceras" limestones are known from various other parts of the world and the study provided a significant contribution to the understanding of these beds.

Publications:

Lubeseder, S. (2008). Palaeozoic low-oxygen, high-latitude carbonates: Silurian and Lower Devonian nautiloid and scyphocrinoid limestones of the Anti-Atlas (Morocco). Palaeogeography, Palaeoclimatology, Palaeoecology, 264(1-2): 195-209

Lubeseder, S., Redfern, J., Boutib, L., (2009), Mixed siliciclastic-carbonate shelf sedimentation- Lower Devonian sequences of the SW Anti-Atlas, Morocco Source: Sedimentary Geology, 215, 1-4, pp. 13-32

Lubeseder S., J. Redfern, L. Petitpierre, S. Fröhlich. (2011). Stratigraphic trapping potential in the Carboniferous of North Africa: developing new play concepts based on integrated outcrop sedimentology and regional sequence stratigraphy (Morocco, Algeria, Libya). Geological Society, London, Petroleum Geology Conference series 2011, v. 7, p. 725-734, doi: 10.1144/?0070725

PhD Thesis:

Stefan Lubeseder 2005: Silurian and Devonian Sequence Stratigraphy of North Africa: Regional?Correlation and Sedimentology (Morocco, Algeria, Libya)

The Numidian Flysch is the most widespread tectono-stratigraphic unit in the western Mediterranean. It outcrops in the Alpine nappe belt, in southern Spain, Morocco, Algeria, Tunisia, Sicily and southern Italy. In Sicily and Tunisia it is an Oligocene to mid-Miocene flysch-type deposit sourced from the north-African passive margin and deposited into an east-west trending foreland basin. This study was supervised by Dr Stephane Bodin and Prof Jonathan Redfern, and undertaken as a PhD by Myron Thomas (now Shell). The study focused on outcrops in northern Sicily and Tunisia, evaluating the sedimentology and provenance within the context of the basin as a whole. Special emphasis is placed upon the controls on deposition and provenance of the clastic supply, which until this study were largely unknown. Future work is intended to extend this study to the west into Algerian and Morocco.

Publications:

Thomas, M. F. H., Bodin, S., Redfern, J., Irving, D. H. B. (2010). "A constrained African craton source for the Cenozoic Numidian Flysch: Implications for the palaeogeography of the western Mediterranean basin." Earth Science Reviews 101, 1. pp 1-23.

Thomas, M.F.H., S. Bodin, J. Redfern Comment on European provenance of the Numidian Flysch in northern Tunisia'by Fildes et al.(2010) Terra Nova 22 (6), 501-503

Lubeseder S., J. Redfern, L. Petitpierre, S. Fröhlich. (2011). Stratigraphic trapping potential in the Carboniferous of North Africa: developing new play concepts based on integrated outcrop sedimentology and regional sequence stratigraphy (Morocco, Algeria, Libya). Geological Society, London, Petroleum Geology Conference series 2011, v. 7, p. 725-734, doi: 10.1144/?0070725

PhD Thesis:

2011: Dr Myron Thomas (now with Shell International): Sedimentology of the Nummidian Flysch - NARG Sponsored.