Sedimentary basins: Resources and thermal history
In front to climate change recognized by the international community, which involve a reduction in the CO2 content of the atmosphere, and the limited reserves of fossil energy, a high-level research on a better understanding of the uranium cycle and on the investigation of sedimentary basins that can generate energy resources (oil or geothermal) or mineral (Fe, Mn, Fluor …) are essential.
Within the framework of the “Resources” project, part of the CNRS interdisciplinary research program NEEDS (Nuclear, Energy, Environment, Waste and Society) and in partnership with AREVA, the conditions of uranium deposition are studied in the Mountain Relief, Basin and Resources team from new microscopic approaches to the source, transport and deposition of uranium and associated elements. The Resource unifying project is co-chaired by a member of the team and each year, Uranium meeting, gathering about 150 people working in different areas upstream of the uranium cycle take place in Orsay.
In the uranium cycle, nuclear waste disposal is a step that is essential to control, which requires a national consortium of laboratories directed in the GNR FORPRO (deep geological FORmation “- CNRS interdisciplinary program” PACEN “- Programme Aval Cycle Energy Nuclear) to which the team is actively involved; but also through collaborations with ANDRA (French agency for radioactive waste management) and the IRSN. The diagenetic evolution of the setting and its regional environment, particularly the evolution of sedimentary paleo-environments, porosity and paleotemperature is one of our specialties.
This expertise led us to propose new models of thermal evolution by combining them with a geophysical modeling. In addition, one of the major goals is to better understand the mechanisms and timing of diagenetic processes controlling reservoir quality, this brings us to develop a high quality research with GDF-Suez, Total, Lundin Petroleum, Vermilion Energy or IFPEN. One of the challenges in diagenesis is to better understand the genesis of deep reservoirs (> 3500m). The “CLAYCOAT – CLAY COATings in shallow marine deposits to improve reservoir quality prediction” is to understand the clay coatings genesis in estuaries and to better constrain their role in the spatial and temporal variability of deep reservoir qualities. A team member is the principal investigator of this research program, involving GDF-Suez, the University of Poitiers, the University of Bordeaux III and the University Paris-Sud. A possible future development in the coming years will be to implement this type of study to better constrain the deep geothermal fields in the Paris Basin.
We are the only laboratory in France mastering the termochronologic fission track and (U-Th) / He methods and ‘Mountain Relief, Basin and Resources” Team performs internationally recognised work in this domain. We are making special efforts for dating fluid flow and geodynamic episodes in conjunction with the basin thermal history. The development and understanding of thermochronolgy method (U-Th) / He on apatite is currently under the ANR (The French National Research Agency) HeDiff program lead by a member of our team. A National Institute for Earth Sciences and Astronomy (INSU) project (CESSUR) and a collaboration with the BRGM is underway on fluorite deposition events dating in the Paris Basin using (U-Th) / He and Sm-Nd methods.
Renewable energy (wind turbine, solar, hybrid / electric car) are large consumers of base metals (Al, Fe, Mn …) but above most critical elements such as rare earth elements, cobalt, tantalum, indium , gallium, selenium … One of the challenges to achieve in good conditions the energy transition in France will be successful future growing supply of these items! For example, fluorite contains fluorine, which is a chemical element essential to the manufacturing of many components allowing France to be a leader in the field of energy, such as using UF6 to separate U isotopes in the manufacture of nuclear fuel, or using hydrofluoric acid (HF) to remove all inorganic oxides in the glass industry, stainless steels (wind and tidal turbines) or semiconductor (photovoltaic, electric car) , or the use of the catalyst F as the reactions of butene in the petroleum refining. In our team, the conditions for mineralization of Mn or F-rich minerals in sedimentary basins are studied under several programs, such as the CNRS (French National Center for Scientific Research) co-operation – CNRST (Morocco National Center for Scientific Research) “Exhumation of the Anti-Atlas domain” or collaboration with the BRGM (French Geological Survey), supported by INSU (National Institute for Earth Sciences and Astronomy) CESSUR program.
The project resources and thermal history in sedimentary basin is very structured at the laboratory scale combining geochemists, sedimentologists, structuralist and modellers on environmental and energy themes, interest strongly the evolution of our society.