SILICEOUS MICROFOSSILS IN A HOLOCENE, HIGH ARCTIC PEAT DEPOSIT (NORDVESTO, NORTHWESTERN GREENLAND)

Siliceous microfossils (diatom valves, chrysophyte stomatocysts, and t estate amoebae plates) were examined from a 2.6-m thick peat deposit f rom Nordvest phi, northwestern Greenland (76 degrees 44'N, 73 degrees 13'W). The moss, predominantly Aplodon worm-skioldii (Hornem.) R.Br., began to accumulate approximately 6500 years ago and persisted for abo ut 2000 years. Siliceous microfossils were generally well preserved in the peat, although taxon richness was low (i.e., only 19 diatom taxa, 16 chrysophyte cyst morphotypes, and 4 testate amoebae general. Despi te the paucity of taxa, marked shifts in species composition were reco rded. Geochemical analyses and biogenic silica determination on the pe at did not show any significant trends. To our knowledge, this study r epresents the first such combined analysis of a High Arctic peat, so o ur interpretations should be considered tentative. Environmental varia bles were not stable during the 2000 years of peat accumulation, as su ggested by microfossil assemblage changes. For example, about 5000 yea rs BP, diatoms reached their maximum relative abundance with taxa indi cative of wetter habitats. We hypothesize that an influx of meltwater to the peat may have occurred at this time, perhaps because of wetter conditions or larger accumulations of snow during winter. These prelim inary data indicate that siliceous microfossil analyses from arctic pe at cores may eventually fine-tune paleoecological inferences for this climatically important region, once the environmental variables determ ining species distributions in peat deposits are determined.