Fluids in the continental crust: decrypting geological processes using noble gases

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The research program will focus on the origin and evolution of fluids in the lithosphere and the critical role they play in the geodynamical evolution of the continental crust. It will address fundamental questions about i) the duration and length of cross-formational fluid flow and its role in the crustal degassing; ii) the existence of fossil water as geological archives of the continental crust evolution; iii) the genesis and evolution of crustal fluids of economic interest, particularly geothermal fluids and shale gas. To meet these objectives, a series of projects will be undertaken in sedimentary and hydrothermal environments - at different spatial and temporal scales. Some focus will be put on the processes responsible for vertical migration of gaseous species (methane, helium…) in aquifers, and the genesis of seepage on continents, with natural laboratory being the St. Lawrence Lowlands (QC). Studies will be aimed at quantifying methane fluxes and model the process of transport from Utica shale. These models will be translated to the Island of Anticosti where tight gas exploitation is sought. Another important aspect that will be explored is the occurrence of hundreds millions to billions years old fluids in deep mining environments and their role in mineralization along the Cadillac fault in Abitibi-Temiscamingue. Parallel to this NSERC research program, we are carrying out a detailed study of the evolution of hydrothermal fluids in the largest active geothermal systems of Mexico in order to assess their lifetime and power capacities. These hydrothermal environments are the modern analogue of the fossil epithermal ore deposits. The large chemical and isotopic database that will be acquired will be crucial to understand the relation between metals and fluid sources in these environments, a premise to future ore genesis models. The tremendous and unique expertise we are developing on geothermal systems will be also applied to the study of the geothermal capacity of some Canadian Provinces, in particular the genesis of the Banff’s geothermal area. The methodological approach to trace the origin and evolution of these “geofluids” is based on the isotopes of conservative elements, namely noble gases, for which I have a unique expertise in Canada. Being chemically inert, scarce and sourced from isotopically distinct reservoirs, noble gases are ideal fluid tracers. Several isotopes are products of radioactive decay, opening opportunities of dating fluids on timescales going to a few years to billions of years. This research program represents a unique opportunity for young HQP to acquire a multi-disciplinary scientific, analytical and professional experience, in the study of the water cycle and its dynamic (behavior) in the continental crust, while specializing in a challenging and rewarding scientific discipline that is the noble gas geochemistry.