Patterns of recent sedimentation in Hudson Bay

Abstract

Hudson Bay is a large Arctic/sub-Arctic shelf sea that covers an area of approximately 841,000 km2, and is estuarine in character, with a large watershed and more than 40 rivers discharging into the bay. Sediment core data for 18 new cores in Hudson Bay was used to understand the processes effecting sedimentation in the bay. This data was interpreted together with sedimentation rates and inventories of 210Pb and 137Cs from previously published articles, archived cores, and geophysical data from the past four decades. Geophysical data shows that the bulk of sedimentation occurs offshore, between 100 and 150 m depth, on the east and northwest coasts of the bay, localized depressions along the southern coast between 50 and 100 m depth, and basins in the center of the bay. Inventories of 210Pb and 137Cs are variable but overall show a trend of lower inventories in the northwest to higher inventories in the southeast. Both geophysical and geochemical data show that sedimentation in the bay is largely transient with sediment deposits at the base of slopes, in localized depressions, and near the mouths of rivers.