Mineralogical, geochemical, and magnetic signatures of surface sediments from the Canadian Beaufort Shelf and Amundsen Gulf (Canadian Arctic)

Abstract

Mineralogical, geochemical, magnetic, and siliciclastic grain‐size signatures of 34 surface sediment samples from the Mackenzie‐Beaufort Sea Slope and Amundsen Gulf were studied in order to better constrain the redox status, detrital particle provenance, and sediment dynamics in the western Canadian Arctic. Redox‐sensitive elements (Mn, Fe, V, Cr, Zn) indicate that modern sedimentary deposition within the Mackenzie‐Beaufort Sea Slope and Amundsen Gulf took place under oxic bottom‐water conditions, with more turbulent mixing conditions and thus a well‐oxygenated water column prevailing within the Amundsen Gulf. The analytical data obtained, combined with multivariate statistical (notably, principal component and fuzzy c‐means clustering analyses) and spatial analyses, allowed the division of the study area into four provinces with distinct sedimentary compositions: (1) the Mackenzie Trough‐Canadian Beaufort Shelf with high phyllosilicate‐Fe oxide‐magnetite and Al‐K‐Ti‐Fe‐Cr‐V‐Zn‐P contents; (2) Southwestern Banks Island, characterized by high dolomite‐K‐feldspar and Ca‐Mg‐LOI contents; (3) the Central Amundsen Gulf, a transitional zone typified by intermediate phyllosilicate‐magnetite‐K‐feldspar‐dolomite and Al‐K‐Ti‐Fe‐Mn‐V‐Zn‐Sr‐Ca‐Mg‐LOI contents; and (4) mud volcanoes on the Canadian Beaufort Shelf distinguished by poorly sorted coarse‐silt with high quartz‐plagioclase‐authigenic carbonate and Si‐Zr contents, as well as high magnetic susceptibility. Our results also confirm that the present‐day sedimentary dynamics on the Canadian Beaufort Shelf is mainly controlled by sediment supply from the Mackenzie River. Overall, these insights provide a basis for future studies using mineralogical, geochemical, and magnetic signatures of Canadian Arctic sediments in order to reconstruct past variations in sediment inputs and transport pathways related to late Quaternary climate and oceanographic changes.

Chronostratigraphy and spatial distribution of magnetic sediments in the Chukchi and Beaufort seas since the last deglaciation

“…Additionally, magnetite was found to be the dominant magnetic mineral and no greigite was found in surface sediments from the Beaufort Sea (Gamboa et al . ). As described in the magnetic mineralogy section, the hysteresis curves, pseudo‐S ratio and MDF NRM , as well as the low MAD values are characteristic of low‐coercivity ferrimagnetic minerals, such as magnetite, yielding reliable PSV data reconstruction (Tauxe et al .…”

Quantifying Provenance and Transport Pathways of Holocene Sediments From the Northwestern Greenland Margin

“…Elemental compositions of sediments were analyzed by energy‐dispersive X‐ray fluorescence (ED‐XRF) spectrometry, using a PANalytical Epsilon 3‐XL. We considered a total of 14 elements (Al, Si, K, Mg, Ca, Ti, Mn, Fe, P, Sr, V, Cr, Zn, and Zr) with analytical procedures similar to Gamboa et al () and Deschamps et al (). Prior to ED‐XRF analysis, loss on ignition was determined gravimetrically by heating the dried samples up to 950 °C for 3 hr.…”

“…Principal component analysis (PCA) was performed on the mineralogical and elemental geochemical datasets with the goal of finding associations with similar relative variation patterns that may be interpreted from a paleoenvironmental standpoint (e.g., Gamboa et al, ; Montero‐Serrano et al, ; von Eynatten et al, , ). A linear discriminant analysis (LDA) was also performed with the potential sediment sources in order to demonstrate the different mineralogical composition of these sources (Figure ).…”

Sediment Provenance Changes in the Western Arctic Ocean in Response to Ice Rafting, Sea Level, and Oceanic Circulation Variations Since the Last Deglaciation

“…Before energy dispersive X‐ray fluorescence analysis, samples were treated by borate fusion in an automated fusion furnace (CLAISSE® M4 Fluxer). The analytical procedures were similar to Gamboa et al (). Analytical accuracy and precision were found to be better than 1–5% for major elements and 5–10% for the other elements, as checked against an international standard (U.S. Geological Survey SDC‐1) and analysis of replicate samples.…”

“…Overall, these grain-size EM obtained by Darby et al (2009) are similar to the ones obtain in this study, and therefore, we infer that our grain-size pattern reflects the same sedimentary processes. However, surface sediments derived from the Mackenzie River are also characterized by a fine to medium grain size (4-5 μm; Gamboa et al, 2017), which is similar to the EM centered on 5 μm that is related to nepheloid transport ). Thus, this EM could be interpreted differently between the Chukchi (nepheloid transport) and Canadian Beaufort margins (Mackenzie River sediment plume).…”