Grant: Discovery Grants Program - Individual

Helium is a noble gas which is also rare in nature, with an average concentration in the Earth's atmosphere of 5.24 ppm. Helium has two isotopes, 3He of primordial origin, and 4He, produced by decay of Uranium and Thorium in rocks. Radiogenic 4He is a strategic resource for its numerous industrial and medical applications, but presently, humanity is facing a worldwide shortage of helium. The reason is the combined increasing demand and decreasing supply, the latter caused by the rarity of high-grade helium reserves in natural gas fields. The genesis of these deposits, some of them known since the early 20e century, are still poorly understood and under investigated. This discovery research program will focus on studying the processes and mechanisms that control helium accumulation in sedimentary basins and how exploitable reserves are formed. Helium requires specific geological conditions to be formed, accumulated and preserved. It is assumed that uranium-rich basement rocks and/or source rocks are the main source. Because of its rarity, it is believed that helium migrates in a carrier gas, such as methane or nitrogen, into geological traps capped by low-permeability salt rocks. All of these conditions are certainly necessary, but not sufficient, to explain the few high-grade helium reserves found worldwide. Indeed, there are still numerous mechanisms and processes which require intense investigation, such as the processes of helium release from rocks into sedimentary fluids. Newly discovered relationships between uranium isotope ratios 234U/238U and 4He/3He ratios by my research group suggests that episodic rock fracturing can release large amounts of helium into the surrounding environment, explaining the presence of large amounts of radiogenic helium in groundwater. It is likely that episodic rock fracturing could also play a role in controlling helium accumulation in high-grade He reserves. Through a multifaceted approach including case studies, laboratory experiments, and modelling, my research program will test the hypothesis of a tectonic control in the release and accumulation of helium in crustal fluids. Short-term objectives are aimed to answer the following questions: What process controls helium release and accumulation in crustal fluids? At what rates? Does tectonics somehow control the formation of high-grade helium resources? The long-term goal is to elaborate robust models of high-grade He genesis and offer reliable geochemical tools for their exploration. This is a timely and urgent problem for Canada and for North America in general, which is exhausting its reserves and loosing its strategic place in this industry. HQP working on the subject will gain scientific knowledge and skills spanning many different disciplines and techniques, which will be precious for future careers in academia or gas/oil industry.