PoLAR-FIT: Pliocene Landscapes and Arctic Remains—Frozen in Time

Abstract

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 biodiversity and landscape response to global warmth are currently 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°C–19°C above modern values, pointing to a much shallower latitudinal temperature gradient than exists today. It appears that the intense Neogene warming caused thawing and weathering to liberate sediment and create a 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 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.RÉSUMÉCe bref résumé présente les résultats choisis d'une enquête en cours sur les déclencheurs qui contribuent à l’amplification du réchauffement de l'Arctique. Les conséquences du réchauffement sur la biodiversité arctique et de la réponse du paysage au réchauffement climatique sont en cours d’être interprété. Des dossiers nord-américains de paysage à grande échelle et le changement paléoenvironnementales durant le Pliocène sont exceptionnellement préservés et scellées dans un état de congélation qui fournissant une occasion pour la reconstruction paléoenvironnementale et faunistique avec une qualité et une résolution sans précédent. Pendent une période de réchauffement global seulement ~2,5°C au-dessus de moderne les dossiers, moléculaire, isotopique, annaux de croissance, paléofaunistique et paléovégétation indiquent que l'Arctique a connu une augmentation de la température annuelle moyenne de 11°C–19°C au-dessus de moderne, en montrant un inferieur gradient de température latitudinal qu'aujourd'hui. Il semble que le réchauffement intense pendent le Néogène a provoqué la décongélation et erosion pour libérer les sédiments et créer une plaine côtière continuel et épaisse (> 2,5 km dans lieux) qui a fourni une route pour les chameaux et autres mammifères pour migrer et évoluer dans l’Haut-Arctique. Dans ce résumé, nous soulignons les opportunités qui existent pour la recherche sur ces sujets et les sujets connexes avec la communauté PoLAR-FIT.

A basal ursine bear (Protarctos abstrusus) from the Pliocene High Arctic reveals Eurasian affinities and a diet rich in fermentable sugars

“…M . americana , a weasel Mustela sp., a meline badger Arctomeles sotnikovae , a three-toed horse Plesiohipparion , a possible cervoid Boreameryx braskerudi of unknown origin, plus an ursine bear “ Ursus abstrusus ” described herein 4 , 32 , 35 . The third author has also identified a duck closest to the Greater Scaup ( Aythya marila ).…”

“…vetus , a small canine dog Eucyon , and a cameline camel (c.f. Paracamelus) 31 , 35 . Of these, Eucyon and Paracamelus had arrived at Eurasia near the Mio-Pliocene boundary, and they may be closely related to the ancestral stock that gave rise to the Eurasian forms.…”

Evolution of woodcutting behaviour in Early Pliocene beaver driven by consumption of woody plants

“…2 ). Rybczynski and Harington 16 , Matthews and Fyles 17 , Hutchison and Harington 18 , Tedford and Harington 10 , Dawson and Harington 19 , Murray et al 20 , Mitchell et al 21 , Gosse et al 22 , and Wang et al 23 provide detailed descriptions of Pliocene terrestrial flora and faunal assemblages associated with the Beaver Pond site.

Figure 2 ( A ) An in-situ macrofossil cone within the Beaver Pond fossiliferous peat deposit.

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“…Ellesmere Island today is a polar desert, with sparse flora and very little precipitation 24 . The landscape was very different during the Early Pliocene warm period, when the climate supported wetland habitat surrounded by open larch forest 10 , 21 , 22 , 25 . During the Pliocene, Ellesmere Island was on the eastern edge of a large coastal plain, where intense Neogene thawing and weathering liberated sediment to create a thick, continuous clastic wedge across the Canadian Arctic Archipelago (referred to as the Beaufort Formation in the western Canadian Arctic islands).…”

“…The remains of a complex faunal community were discovered at the Beaver Pond site, including beaver (Dipoides sp., see below), three-toed horse, bear, badger, "deerlet", water fowl, fish and a rabbit relative 10,22 . Pliocene-age sites with similar fauna and flora community composition are very rare-Idaho in mid-continent North America, and the high altitude Yushe Basin, in northeastern China are the only known sites with similar (but not equivalent) faunal assemblages 37,38 .…”