Sources of sediment found in sea ice from the western Arctic Ocean, new insights into processes of entrainment and drift patterns

The geochemical fingerprint of entrained Fe oxide mineral grains in Arctic Ocean sea ice is used to determine precise sources of this sediment. This approach substantiates the importance of the Laptev Sea as a source of sea ice and even the presence of Russian ice in the Beaufort Sea off Alaska. Fe oxide grains from the Laptev Sea were found in floes in the Beaufort Sea, Chukchi Borderland, and central Arctic Ocean, demonstrating the importance of sea ice in distributing itself throughout the Arctic Ocean and the potential of transporting sediment from Russian rivers to North American shelves. Banks Island shelf is the most important source of sediment sampled from ice floes in the Beaufort Sea, northern Chukchi Sea, and Chukchi Borderland area. Although most of the entrained sediment fits the criteria for suspension freezing in shallow water, the presence of winter polynyas with offshore winds and not the size of shallow areas appears to be the critical factor for sea ice entrainment. Seven of the 18 ice floes sampled contained Fe oxide grains from more than one source area. The two most common sources that are found in the same ice floes are Banks Island and the Laptev Sea. Multiple sources in ice floes suggest that either mingling of fragmented ice floes occurs or that a source area containing grains from both these sources has yet to be located. The addition of fine, sand-sized, windblown sediment is not thought to be significant.