sedimentary geology; coastal deposits; Pleistocene; Holocene; global changes; sea-level changes; eolianite; carbonate; coastal dune; forward modelling; image analysis; sedimentology eolianite petroleum; geology paleoclimatology sealevel; changes Quaternary Holocene Pleistocene
Frébourg G., Davaud E., Virgone A., Gaillot J., Kamali M. (2010), An aeolianite in the upper Dalan member (Khuff formation), South pars field, Iran., in Journal of Petroleum Geology
, 33, 141-154.
Frébourg G. (2010), Carbonate coastal dunes: potential reservoir rocks ?, in Terre et Environnement
, 92, 1-178.
Frébourg G., Hasler C.A., Davaud E. (2010), Catastrophic event recorded among Holocene eolianites (Sidi Salem Formation, SE Tunisia)., in Sedimentary Geology
, 224, 38-48.
Frébourg G., Hasler C.A., Le Guern P., Davaud E. (2008), Facies and characteristics in carbonate eolianites., in Facies
, 54(2), 175-191.
Hasler C.A., Frébourg G., Davaud E., Anatomy, internal heterogeneities, and early fracture network of a Pleistocene carbonate coastal dune (Rejiche Formation, southeastern Tunisia), in Facies
Frébourg G., Hasler C.A., Davaud E., Uplifted marine terraces of the Akamas Peninsula (Cyprus): evidence of climatic conditions during the Late Quaternary highstands., in Sedimentology
Eolianites form huge sand bodies extending in some places over hundreds of kilometres along Holocene and Pleistocene coastlines, but they have been very seldom reported in pre Quaternary sedimentary sequences. This paradox has prompted several authors to suggest that eolianites only form during ice ages and are genetically related to rapid glacio-eustatic fluctuations of sea level.Several clues indicate, however, that eolian limestones are much more frequent in the fossil record than suggested, and that their apparent scarcity results from the difficulty of distinguishing them from shallow marine deposits.There are two main reasons why a better understanding of the climatic/eustatic conditions in which these deposits are preserved, and why the development of tools to identify them in the fossil record at the core or thin section scale are important:- from an economic perspective, eolianites represent huge and continuous volumes of sand that are characterized by high primary and secondary porosity. In the fossil record, they could constitute important aquifers and oil or gas reservoirs.- from an ecological viewpoint, carbonate coastal dunes may lithify very quickly and form hydrodynamic barriers that slow down coastal erosion. Their preservation along the present-day coastlines could reduce the devastating effects of a rising sea level.During the previous project (107694/1), we demonstrated that classical petrographic criteria to recognise eolian sediments (well sieved, fine grained and laminated sands) are exceptional in carbonate dunes, as wind carbonate deposits are mainly heterogeneous in size and often coarse-grained. Our experimental works on the influence of percolating fluid on grains packing have shown that the fluid affects grain orientation, but the major reorganising phase take place during evaporation, and can significantly reduce porosity. We have also studied the interaction between fluids and sediments in the field, and important results have been obtained on the eolianites’ early diagenesis: preferential precipitation of carbonate cement around quartz has been observed for the first time, and is presented as a new indicator of vadose diagenesis. The importance of primary depositional facies on early cements and fractures has also been quantified. A detailed study of the sedimentary sequence of carbonate coastal dunes allowed us to recognise seasonal trends. Our project’s aim is to continue and extend the work done in the previous project by:- comparing the petrographic composition of present day and Holocene eolianites;- testing the icehouse hypothesis on the climatic/eustatic conditions surrounding the formation of eolianites by re-examining shallow-water facies for a possible eolian origin in the pre-Quaternary sedimentary record at the outcrop level and on cores (Cretaceous Delphino-Helvetic units, Mesozoic Middle East oil fields);- complete the laboratory experiments on the role of percolation of fluids and desiccation of sediment on grain packing, test the value of this post-depositional criterion as a paleoclimatic proxy and study its influence on reservoir properties;- looking for the presence of submerged eolian ridges developed during the last post-glacial transgression using existing echo-sounding, side-scan sonar, and high resolution seismic data-sets;- evaluating the petrophysical heterogeneities and the reservoir potential of eolianites by studying their diagenetic evolution of subaerial exposure through time;- improving the recognition criteria at core and thin section scale;- introducing onshore transportation as an important process in 2D simulation models.