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The Hudson Bay Basin is the largest intracratonic basin in North America but also the least known from a geological point of view and the only one without hydrocarbon production and reserves. The Hudson Bay Basin, in north-central Canada, is bounded by smaller satellite basins, Moose River Basin to the south and Foxe and Hudson Strait basins to the north. It was explored for hydrocarbons from the late 1960's to the mid 1980's. However, after the drilling of five offshore wells, the industry stopped exploration programs as the basin was considered to be thermally immature with a too thin succession and problematic source rock distribution. As part of its new Geomapping for Energy and Minerals program, the Geological Survey of Canada included the Hudson Bay Basin in its research portfolio with the goal to generate a modern understanding of the geological framework of the basin and a precise knowledge of its hydrocarbon systems. The Hudson-Foxe basins GEM-1 project benefited from limited but significant research activities before its official launch in 2008. The evaluation of recent and vintage geoscientific data led to the definition of the most pertinent research activities and the development of collaborative networks with provincial, territorial and academia stakeholders. The first phase of the research led to the proposal of modern stratigraphic frameworks at the local (provincial, territorial) and regional (offshore) scales and extensive geochemistry works on hydrocarbon source rocks and their burial and thermal histories. Satellite data were acquired over the entire offshore domain of the Hudson Bay and Foxe basins in the search for evidence for active hydrocarbon systems. After the completion of Phase 1 (2008-2013), a new round of research activities were defined as part of the GEM-2 program (2013-2020). For the new Hudson Bay - Ungava project, research activities were defined aiming to understand local and/or regional factors responsible for burial and exhumation histories as they pertain to regional or local hydrocarbon prospectivity. The research led to a basin-scale stratigraphic framework coupled with detailed analyses of hydrocarbon generation and appraisal of the best potential reservoir unit. GEM supported research for the intracratonic Hudson Bay, Foxe and Moose River basins has resulted, in early 2019, in the publication of 14 peer-reviewed papers, 43 Open File reports (GSC, CNGO, GC, MGS and OGS), 13 GSC paleontological reports, 11 B.Sc. theses and 1 M.Sc. thesis. The main conclusion of the 11 years of research suggests that the Hudson Bay Basin has an oil potential likely significant compared to the belief at the start of the research and integration of the multiple data set allows to propose Paleozoic-Cenozoic filled half grabens as the potential most significant hydrocarbon play of the basin.

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Hydrothermal dolostone is one of the major producing hydrocarbon reservoirs in intracratonic basins in North America. The Hudson Platform is the largest intracratonic basin in North America but it is also the least explored. A first round of exploration took place from 1968-1985 period and resulted with the drilling of 5 dry wells in the central part of Hudson Bay and a few dry wells onshore Manitoba and Ontario. The first round of exploration occurred before the recognition of the economic significance of fault-controlled dolostone bodies. Fault-controlled porous dolostone and dolostone breccia, interpreted to be hydrothermal have been identified at two localities along the northern shore of Southampton Island (northern Hudson Bay). The dolostone breccia is partly cemented by saddle dolomite cement with up to 25% open pore space. In a well drilled near the town of Churchill in NE Manitoba, a 14 m interval of brecciated dolostone with dissolution porosity and partial infill by saddle dolomite cement was identified. In one part of this interval, dolomitization and silicification are physically associated to a vertical fracture that has been crosscut by the core. Oxygen and carbon stable isotope analyses of the dolomite cement yielded very negative ?18O ratios similar to those of coeval hydrothermal dolomite in other intracratonic basins. In the absence of microthermometric fluid inclusion data, the interpretation as being the result of precipitation from a high temperature fluid is still a working hypothesis. The delta13C ratios can be very negative, a situation commonly associated with the presence of biogenic-derived bicarbonate ions in the diagenetic fluid. The delta18O ratios of groundmass fabric-retentive dolomite have been acquired to compare with those of the saddle dolomite; the former yielded slightly more negative values than those of Upper Ordovician seawater and suggest that groundmass dolomitization likely proceeded from near marine fluid at slightly elevated temperature.