Panoramic view across the Atlantic side of the Pyrenees, with the summit of Mont Perdu (Pyrenees, 2006). © BRGM - Pierre Vassal

Convergence, a multiannual research partnership between the BRGM and Total

08.09.2016
The BRGM and Total have signed an agreement on research to gain a new understanding of the geodynamic evolution of mountain ranges and its impact on the formation of hydrocarbons. Two projects, "Orogen" and "Source to sink", are focusing on the Pyrenees range, the subject of the first full-scale project for the French Geological Reference Platform.

As longstanding partners, the BRGM and Total have just signed a new framework agreement called "Convergence" (2015- 2020), which will employ about a dozen full-time researchers. The  aim  is to develop new approaches to understand the formation and evolution of mountain ranges in collision zones and  to reconsider the processes involved in the distribution and  transformation of organic matter from which hydrocarbons were formed and in the formation and location of the reservoirs in which  they are found. Through Convergence, the BRGM and Total are working in synergy on scientific and industrial issues.

The scientific programme for the French Geological Reference Platform and its regional projects will improve knowledge on the geology of France through 3D mapping and geometry. Shown here is an extract from the 1/50 000 RGF geological map of the Pyrenees draped over a digital altitude model. © BRGM

The scientific programme for the French Geological Reference Platform and its regional projects will improve knowledge on the geology of France through 3D mapping and geometry. Shown here is an extract from the 1/50 000 RGF geological map of the Pyrenees draped over a digital altitude model. © BRGM

Orogen: identifying the "DNA" of mountain ranges

As "Orogen", explains Thierry Baudin, the  scientific manager of the  RGF programme, "is a holistic  project that aims to understand the nature of mountain ranges and the fundamental parameters that govern their formation and evolution. The idea is to identify the "DNA", so to speak, of orogens. The Pyrenees are of particular interest in this respect. They are an anomaly among the world's mountain ranges, because they exhibit an entire orogenic cycle, from the original exhumation of mantle rock with rupturing of the continental plate to the first convergence movement, and through to the destruction of the range with the breakaway of the Corsica-Sardinia block followed by closure of the basin."

The researchers will focus on  understanding the impact of the deep geological organisation of mountain ranges on their tectono-sedimentary evolution.

"These studies", explains T. Baudin, "which will also involve the INSU* and universities, will draw on every kind  of research  conducted on the  Pyrenees  in the last hundred years and more, which will be collected and synthesised. Sixteen PhD candidates and eleven post-docs will be involved, working in some fifteen laboratories in France and elsewhere."

Geologists on a field mission in the Pyrenees.

Geologists on a field mission in the Pyrenees.© BRGM

"Source to sink": from hydrocarbon sources to storage

"The Source-to-Sink project", says geologist Jean-Yves Roig, "includes a component focusing on the  compressive Pyrenean context, which  affects the  entire west  European coast.  It aims to further knowledge on the processes involved in the creation and erosion of mountain reliefs and on the parameters that govern sediment deposits in downstream basins. The project  will draw on observations, characterisation and  dating of the weathered surfaces that mark the end of mechanical erosion of the relief, which will help to understand the evolution of sedimentary systems and to constrain modelling of the processes involved in the relief's destruction over time and space."

Another component will focus on French Guiana's passive margins, formed by sediment deposit in the ocean:  "we hope  to get a clearer picture,  on land, of the periods when  mechanical erosion and chemical weathering ( formation of lateritic surfaces) were taking place, which  we will then correlate  with  the geometry and typology of marine deposits."

This is of obvious interest to both parties: a better understanding of these mechanisms will help Total to assess resource potential during explorations and  to  improve their management of the  latter, while advances in the  understanding of weathered surfaces and  sedimentary systems are  a promising prospect for the  BRGM as they could  produce numerous applications in the fields of mineral and hydrogeological resources, natural risks, spatial planning and geothermal energy production.

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