Some Pollen Profiles from Arctic Alaska

Livingstone, D

A three-zone pollen chronology has been established for the region surrounding the central Brooks Range in northern Alaska. The oldest of these zones, characterized by herbaceous tundra vegetation, appears to be contemporary with the Eschooka glaciation. The youngest of these zones, characterized on the north side of the Brooks Range by tundra with shrubs and on the south side by hemiarctic vegetation, appears to include a weakly developed postglacial thermal maximum. The longest core contains, in its herbaceous zone, evidence of a temporary climatic deterioration similar to Zone III of the European pollen chronology. The sediments in which the evidence occurs are laminated. The NAP/AP ratio of surface samples from a number of tundra lakes is much lower than the 1:1 that is usually taken to represent the division between forest and tundra. About 50 different pollen and spore types were identified in the material. The principal pollen types were Betula, Alnus, Picea, Salix and Cyperaceae. Vegetational changes during the time represented by the samples studied appear to have been much less striking than those of the temperate zone during the same time. This supports the view that the arctic unglaciated areas have served as glacial-age refugia for very many of the plants living in them today.

Some Pollen Profiles from Arctic Alaska

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