Holocene Soligenous Fens on a High Arctic Fault Block, Northern Ellesmere Island (82°N), N.W.T., CANADA

Abstract

Exceptionally thick (4 m) autochthonous peat deposits were investigated on a high arctic fault block in the foothills of the Grant Land Mountains, northern Ellesmere Island (82°N). These organic sediments are rich in macrofossils, and contained undecomposed lichen thalli, bryophytes, Dryas integrifolia plants, arctic hare coprolites, and bird bones. A quantitative macrofossil analysis (percent volume) was done on four of the deposits for paleoenvironmental interpretation. Twenty-eight species of mosses from the peat sections represent 25% of the extant moss flora and occur in analogous contemporary assemblages. Four species are new to the North American fossil record. The dominant peat-forming mosses were Philonotis fontana, Tomenthypnum nitens, Aulacomnium spp., Hylocomium splendens, and Tortula ruralis. The chronology indicates a minimum date for peat formation of 6315 BP (S-2449). The youngest sample dated was 760 BP (S-2449), though surface assemblages indicate extant peat-forming assemblages. The subfossil analyses show that a diverse moss flora was present on the fault block prior to the mid-Holocene.

The species composition and rates of net organic accumulation are highly variable for concurrent intervals within adjacent peats. This variability demonstrates that changes in local hydrology and slope processes dominate over macroclimatic changes. This precludes a simple model for soligenous fen development in the High Arctic.