Document generated on 09/30/2021 2:17 p.m. Geoscience Canada Journal of the Geological Association of Canada Journal de l’Association Géologique du Canada PoLAR-FIT Pliocene Landscapes and Arctic Remains—Frozen in Time J.C. Gosse, A.P. Ballantyne, J.D. Barker, A.Z. Csank, T.L. Fletcher, G.W. Grant, D.R. Greenwood, R.D.E. MacPhee and N. Rybczynski Volume 44, Number 1, 2017 Article abstract This short summary presents selected results of an ongoing investigation into URI: https://id.erudit.org/iderudit/1039606ar the feedbacks that contribute to amplified Arctic warming. The consequences of warming for Arctic biodiversity and landscape response to global warmth See table of contents are currently being interpreted. Arctic North American records of largescale landscape and paleoenvironmental change during the Pliocene are exquisitely preserved and locked in permafrost, providing an opportunity for Publisher(s) paleoenvironmental and faunal reconstruction with unprecedented quality and resolution. During a period of mean global temperatures only ~2.5°C above The Geological Association of Canada modern, the Pliocene molecular, isotopic, tree-ring, paleofaunal, and paleofloral records indicate that the High Arctic mean annual temperature was ISSN 11–19°C above modern values, pointing to a much shallower latitudinal temperature gradient than exists today. It appears that the intense Neogene 0315-0941 (print) warming caused thawing and weathering to liberate sediment and create a 1911-4850 (digital) continuous and thick (>2.5 km in places) clastic wedge, from at least Banks Island to Meighen Island, to form a coastal plain that provided a highway for Explore this journal camels and other mammals to migrate and evolve in the High Arctic. In this summary, we highlight the opportunities that exist for research on these and related topics with the PoLAR-FIT community. Cite this article Gosse, J., Ballantyne, A., Barker, J., Csank, A., Fletcher, T., Grant, G., Greenwood, D., MacPhee, R. & Rybczynski, N. (2017). PoLAR-FIT: Pliocene Landscapes and Arctic Remains—Frozen in Time. Geoscience Canada, 44(1), 47–54. All Rights Reserved © The Geological Association of Canada, 2017 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ GEOSCIENCE CANADA Volume 44 2017 47 ARTICLE SUMMARY This short summary presents selected results of an ongoing investigation into the feedbacks that contribute to amplified Arctic warming. The consequences of warming for Arctic bio- diversity and landscape response to global warmth are current- ly being interpreted. Arctic North American records of large- scale landscape and paleoenvironmental change during the Pliocene are exquisitely preserved and locked in permafrost, providing an opportunity for paleoenvironmental and faunal reconstruction with unprecedented quality and resolution. During a period of mean global temperatures only ~2.5°C above modern, the Pliocene molecular, isotopic, tree-ring, paleofaunal, and paleofloral records indicate that the High Arctic mean annual temperature was 11–19°C above modern values, pointing to a much shallower latitudinal temperature gradient than exists today. It appears that the intense Neogene PoLAR-FIT: Pliocene Landscapes and Arctic warming caused thawing and weathering to liberate sediment and create a continuous and thick (>2.5 km in places) clastic Remains—Frozen in Time wedge, from at least Banks Island to Meighen Island, to form J.C. Gosse1, A.P. Ballantyne2, J.D. Barker3,4, A.Z. Csank5, a coastal plain that provided a highway for camels and other T.L. Fletcher2, G.W. Grant4, D.R. Greenwood6, mammals to migrate and evolve in the High Arctic. In this R.D.E. MacPhee7 and N. Rybczynski8 summary, we highlight the opportunities that exist for research on these and related topics with the PoLAR-FIT community. 1Department of Earth Sciences, Dalhousie University 1459 Oxford St, Halifax, Nova Scotia, B3H 4R2, Canada RÉSUMÉ Email: [email protected] Ce bref résumé présente les résultats choisis d’une enquête en 2 cours sur les déclencheurs qui contribuent à l’amplification du College of Forestry and Conservation, University of Montana réchauffement de l’Arctique. Les conséquences du réchauffe- 32 Campus Drive, Missoula, Montana, 59801, U.S.A. ment sur la biodiversité arctique et de la réponse du paysage au 3School of Earth Sciences, The Ohio State University réchauffement climatique sont en cours d’être interprété. Des Marion, Ohio, 43302, U.S.A. dossiers nord-américains de paysage à grande échelle et le changement paléoenvironnementales durant le Pliocène sont 4 Byrd Polar and Climate Research Centre exceptionnellement préservés et scellées dans un état de con- Columbus, Ohio, 43210, U.S.A. gélation qui fournissant une occasion pour la reconstruction 5Department of Geography at the University of Nevada Reno paléoenvironnementale et faunistique avec une qualité et une 1664 N Virginia Street, Reno, Nevada, 89557, U.S.A. résolution sans précédent. Pendent une période de réchauffe- ment global seulement ~2,5°C au-dessus de moderne les 6Department of Biology, Brandon University dossiers, moléculaire, isotopique, annaux de croissance, paléo- 270 18th Street, Brandon, Manitoba, R7A 6A9, Canada faunistique et paléovégétation indiquent que l’Arctique a 7Department of Mammalogy, Division of Vertebrate Zoology connu une augmentation de la température annuelle moyenne American Museum of Natural History, de 11–19°C au-dessus de moderne, en montrant un inferieur Central Park West at 79th Street gradient de température latitudinal qu’aujourd’hui. Il semble New York, New York, 10024-5192, U.S.A. que le réchauffement intense pendent le Néogène a provoqué la décongélation et erosion pour libérer les sédiments et créer 8Canadian Museum of Nature une plaine côtière continuel et épaisse (> 2,5 km dans lieux) PO Box 3443, Station D, Ottawa, Ontario, K1P 6P4, Canada qui a fourni une route pour les chameaux et autres mam- Geoscience Canada, v. 44, https://doi.org/10.12789/geocanj.2017.44.116 pages 47–54 © 2017 GAC/AGC® 48 J.C. Gosse, A.P. Ballantyne, J.D. Barker, A.Z. Csank, T.L. Fletcher, G.W. Grant, D.R. Greenwood, R.D.E. MacPhee and N. Rybczynski Figure 1. Map of Arctic North America with geographic features described in the text. Previous ‘Pliocene Landscape and Arctic Remains—Frozen In Time’, (PoLAR-FIT) sites include: BP –Beaver Pond, BB –Ballast Brook, EL –Ekblaw Lake, FLB –Fyles Leaf Bed, GAP –‘The Gap’ on Meighen Island, RS –Remus Section, WCG –White Channel Gravel in the Klondike District, Yukon. The blue outline represents the modern onshore distribution of Beaufort Formation (Fyles et al. 1994). The original Beaufort For- mation has been interpreted by others to have formed a continuous Arctic Coastal Plain from Banks Island to Meighen Island, and possibly from the Mackenzie Delta to beyond Axel Heiberg Island. North Polar Projection DEM constructed with GEOMAPAPP v 3.6.4 using International Bathymetric Chart of the Arctic Ocean v 3, 30 arc- second resolution. mifères pour migrer et évoluer dans l’Haut-Arctique. Dans ce ably replicating low-latitude temperature proxies (Salzmann et résumé, nous soulignons les opportunités qui existent pour la al. 2013). The collective record suggests that there may be recherche sur ces sujets et les sujets connexes avec la commu- feedbacks that are not adequately represented by the models. nauté PoLAR-FIT. Temperature, humidity, CO2, and continentality may be con- trolled by factors such as different forest types and densities, INTRODUCTION sea-ice cover, the effects of forest fires, and the possibility that Today’s thawing of permanently frozen Pliocene clastic sedi- ocean circulation through the High Arctic was limited until the ments and organic layers in Arctic Canada and Alaska (Fig. 1) Beaufort Formation was incised and the Northwest Passages provides access to exquisitely preserved, sub-fossilized floral, were opened. Despite the discovery of well-preserved wood faunal, molecular, and isotopic records. These records docu- by explorers on Banks Island 150 years ago (Heer 1868), the ment amplification of temperature change in polar regions paleoenvironmental and paleoclimate research is still in its (e.g. Ballantyne et al. 2013) during periods of global warmth on infancy and the biochronostratigraphy is too imprecise to test the magnitude predicted for our next century (Masson-Del- synchroneity and reconcile the disparities among the sites. Fur- motte et al. 2013). The Pliocene sediments exposed onshore, thermore, accelerated processes such as retrogressive thaw including the Beaufort Formation, span a variety of deposi- slumping is rapidly removing or exposing previously tional environments (marine, lacustrine, paludal, alluvial, flu- entombed sedimentary, macrofossil, and biochemical records vial, and possibly glacial) over a wide temporal range (ca. 3.8 to before they can be examined within their stratigraphic context. 2.6 Ma; see later discussion of Geochronology), including To tackle these challenges, an international multidiscipli- varves and possible annual couplets of sand and leaf layers nary team has assembled with the shared objective of studying spanning a millennium. Until recently (e.g. Feng et al. 2017) these systems in an integrated way. The represented disciplines numerical models of Pliocene climate were unable to repro- include paleoclimatology, geomorphology, geochronology, duce the high paleo-temperatures in the High Arctic while reli- biogeochemistry, dendroclimatology, floral and faunal paleon- http://www.geosciencecanada.ca GEOSCIENCE CANADA Volume 44 2017 49 tology, evolutionary biology, and landscape ecology. Members Table 1. Founding PoLAR-FIT members. of the ‘Pliocene Landscape and Arctic Remains—Frozen In Time’, or PoLAR-FIT working group span from early-career to senior Ballantyne, A.