Neogene and early Pleistocene flora from Alaska and Arctic/Subarctic Canada: New data, intercontinental comparisons and correlations

Abstract

A new correlation scheme primarily concerning macroand meso-floral remains of bryophytes and vascular plants from 26 Neogene sites and over 50 florules in Alaska and northern Canada is presented. Flora are valuable for correlating Arctic Neogene sites, especially where absolute dating methods are not possible. These taxa clearly differentiate Neogene from Quaternary deposits in the North American Arctic. Recent age estimates provided using terrestrial cosmogenic nuclide (TCN) dating provide tiepoints for these correlations and tend to confirm earlier dates achieved by relative and correlative methods. Our knowledge of North American Arctic/Subarctic palaeofloras and faunas is sufficiently detailed to allow inter-regional comparisons. This paper contains the first attempt to compare and contrast Neogene and early Pleistocene macroand meso-floras from the entire circum-Arctic region. The subfossil and fossil floras are valuable for understanding the evolution of the boreal realm, from the qualitatively different composition of the communities of the Neogene Arctic, to those of the more southerly modern boreal region. These differences may be due to the warm climate of the Neogene Arctic combined with the long dark of polar winter – a phenomenon with no modern analogue. The differences highlight the need for a comprehensive understanding of species’ ecology to predict species ranges under near-future climate conditions analogous to our Neogene past. Many sites described here present rich opportunities for future cross-disciplinary study, including research related to the role of warm-climate intervals in patterning past and present Arctic ecosystems. T.L. Fletcher. Key Laboratory of Forest Ecology and Management, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang, Liaoning 110164, China and College of Forestry and Conservation, University of Montana, Missoula, Montana 59812, United States of America. drtlfletcher@gmail.com A. Telka. PALEOTEC Services – Quaternary and late Tertiary plant macrofossil and insect fossil analyses, 1-574 Somerset St. West, Ottawa, Ontario K1R 5K2, Canada. N. Rybczynski. Department of Palaeobiology, Canadian Museum of Nature, Ottawa, Ontario K1P 6P4, FLETCHER ET AL.: ARCTIC MACROFLORA 2 Canada. nrybczynski@nature.ca and Department of Biology and Department of Earth Sciences, Carleton University, Ottawa, Ontario K1S 5B6, Canada. nrybczynski@gmail.com J.V. Matthews, Jr. 1 Cricket Lane, Hubley, Nova Scotia B3Z 1A5, Canada.