Ice-rafted sediments of the Yermak plateau and fram strait: new data on spore-pollen spectra, mineralogy and geochemistry
The results of geochemical, mineralogical and palynological study of ice-rafted sediments (IRS) of the Yermak Plateau (Arctic Ocean) are presented. The complex analysis of IRS allowed us to identify their sources and direction of transport. According to X-ray difractometry, the mineral composition of IRS of the Yermak Plateau and Fram Strait is similar. Distribution of trace elements and rare earth elements (REE) in IRS from the areas of the western sector of the Arctic Ocean also indicate their similar sources. These conclusions are consistent with present-day direction of the Arctic ice drift from the coasts of Alaska, Chukotka and East Siberian Sea and Laptev Sea toward the Atlantic Ocean. The morphology of quartz of IRS indicates their predominantly water transfer. According to palynological analysis, the IRS spore-pollen spectra (SPS) are dominated by pollen of anemophilous plants (pine, birch, and cereals) suggesting important role of atmospheric transport of the IRS from the Yermak Plateau. No correlation, however, is found between SPS composition and the distance between sampling points, which is evidence of the presence of other IRS sources. The fndings of freshwater algae, fragments of plant tissue, moss and fungi spore and helophytes pollen in the IRS confrms their continental source. The presence of marine diatom valves suggests that the samples from the Yermak Plateau and Fram Strait contain sedimentary material captured by ice roiling of the surface layer of bottom sediments in the shallow areas of the Siberian Arctic shelf, as well as diatom valves arriving with splashes from drifting ice openings.
Figures 15. Tables 3. References 33.
Key words: Arctic, ice-rafted sediments, mineralogy, geochemistry, palynology.
МINERALOGY № 4 2018