Sedimentary Processes Within the Canadian Arctic Archipelago: Relationships Among Sedimentological, Geochemical, and Magnetic Sediment Properties

Sarah Letaïef (1) , Jean-Carlos Montero-Serrano , Guillaume St-Onge

1 Géosciences Montpellier

The sedimentological, geochemical, physical and magnetic properties of 40 surface and basal sediment samples of box cores collected throughout the Canadian Arctic Archipelago (CAA) from the Canadian Beaufort Shelf to Lancaster Sound were analyzed to determine the sedimentary processes that operate within the CAA during the pre- and post-industrial periods (i.e., before and after 1900 Common Era or CE). In addition, the chronology of seven selected regional cores was established using ²¹⁰Pb measurements, where the base is dated between 1550 and 1820 CE. These cores provide an opportunity to robustly compare post-1900 sedimentary conditions with those of the colder Little Ice Age period (LIA; ∼1500-1900 CE). The different properties combined with multivariate statistical analyses result in the identification of three regional provinces with distinct sedimentary characteristics: (a) the West province (Mackenzie Shelf/Slope, west Banks Island and M'Clure Strait) typified by detrital associations (Fe-Rb-Ti-Zn), high organic matter inputs, dominance of magnetite and low-coercivity minerals and high aluminosilicate contents; (b) the Intermediate Zone (Amundsen and Coronation gulfs) distinguished by Si-Al-Zr-Sr-K associations, Mn oxyhydroxides precipitation, constant high magnetic grain concentrations and a mixture between marine and terrigenous organic matter; and (c) the East Province (Queen Maud Gulf, Victoria and Barrow straits, and Lancaster and Eclipse sounds) described by high detrital carbonate inputs, marine organic matter, a dominance of high-coercivity minerals and high magnetic concentrations in pre-industrial samples. Our results confirm that the pre- and post-industrial sedimentary dynamics are controlled by sediment supplies from the river discharges in the West and Intermediate provinces, whereas the East province is more influenced by sea ice and coastal erosion. Basal sediment samples from the seven ²¹⁰Pb-dated cores suggest an intensification of the Mackenzie, Coppermine, and Ellice rivers runoff, extensive sea-ice cover and consequently sediment transport by the latter during the LIA period.

Mots clés: sedimentology; environmental magnetism; geochemistry; sedimentary processes

Domaines: Planète et Univers [physics]

Sarah Letaïef, Jean-Carlos Montero-Serrano, Guillaume St-Onge. Sedimentary Processes Within the Canadian Arctic Archipelago: Relationships Among Sedimentological, Geochemical, and Magnetic Sediment Properties. Geochemistry, Geophysics, Geosystems, 2021, 22, ⟨10.1029/2021GC009719⟩. ⟨insu-03661290⟩