The Hudson Bay Lowland: major geologic features and assets

Abstract

The Hudson Bay Lowland is a vast (325,000km2), flat (average slope 0.5m/km) physiographic region of Canada located to the southwest of James Bay and Hudson Bay. It is underlain by Paleozoic and Mesozoic rocks and bounded by Precambrian terrains. Thin Pleistocene till sheets, locally deposited on fluted terrains mantle most of the Lowland, and they are overlain by thin marine and coastal Holocene deposits which have formed during the ongoing regression from an early post-glacial sea, the Tyrrell sea. The present shores of the James Bay and Hudson Bay are but one stage of development of such regressive sequences. More than 90% of the vast emerged Lowland is covered by one of the largest cold wetlands and peatlands of the world. Up to 3-4m thick peats have developed in the last 5000 years in inland fens and raised bogs. Fresh water is the major resource of the area, both for hydroelectric power and/or irrigation on a continent wide scale. Other resources not yet fully evaluated, consist of mineral deposits on or near Precambrian inliers, hydrocarbons in the relatively thin Paleozoic sequence, and lignite, kaolin and quartz sand in Mesozoic terrains. The damage generated by any development in the area, must be carefully weighted against the worldwide importance of this vast peatland on gaseous fluxes and atmospheric balance. Furthermore the coastal zone of the Lowland is a major staging and breeding ground for polar bears, migratory birds and other species. Perhaps assurance of preservation of the still pristine natural Hudson Bay Lowland should be achieved by establishing it as an international heritage park.