Oceanography The Official Magazine of
The Oceanography Society
Volume 24 Issue 03

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Volume 24, No. 3
Pages 66 - 80

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A Synthesis of the Long-Term Paleoclimatic Evolution of the Arctic

Matthew O’Regan Christopher J. WilliamsKaren E. Frey Martin Jakobsson
Article Abstract

Since the Arctic Ocean began forming in the Early Cretaceous 112–140 million years ago, the Arctic region has undergone profound oceanographic and paleoclimatic changes. It has evolved from a warm epicontinental sea to its modern state as a cold isolated ocean with extensive perennial sea ice cover. Our understanding of the long-term paleoclimate evolution of the Arctic remains fragmentary but has advanced dramatically in the past decade through analysis of new marine and terrestrial records, supplemented by important insights from paleoclimate models. Improved understanding of how these observations fit into the long-term evolution of the global climate system requires additional scientific drilling in the Arctic to provide detailed and continuous paleoclimate records, and to resolve the timing and impact of key tectonic and physiographic changes to the ocean basin and surrounding landmasses. Here, we outline the long-term paleoclimatic evolution of the Arctic, with a focus on integrating both terrestrial and marine records.

Citation

O’Regan, M., C.J. Williams, K.E. Frey, and M. Jakobsson. 2011. A synthesis of the long-term paleoclimatic evolution of the Arctic. Oceanography 24(3):66–80, https://doi.org/10.5670/oceanog.2011.57.

References

Aagaard, K., and E.C. Carmack. 1989. The role of sea ice and other fresh water in the Arctic circulation. Journal of Geophysical Research 94:14,485–14,498, https://doi.org/10.1029/JC094iC10p14485.

Backman, J., M. Jakobsson, M. Frank, F. Sangiorgi, H. Brinkhuis, C. Stickley, M. O’Regan, R. Løvlie, H. Pälike, D. Spofforth, and others. 2008. Age model and core–seismic integration for the Cenozoic Arctic Coring Expedition sediments from the Lomonosov Ridge. Paleoceanography 23, PA1S03, https://doi.org/10.1029/2007PA001476.

Backman J., and K. Moran. 2009. Expanding the Cenozoic paleoceanographic record in the Central Arctic Ocean: IODP Expedition 302 Synthesis. Central European Journal of Geosciences 1(2):157–175, https://doi.org/10.2478/v10085-009-0015-6.

Ballantyne, A.P., D.R. Greenwood, J.S. Sinninghe–Damsté, A.Z. Csank, J.J. Eberle, and N. Rybczynski. 2010. Significantly warmer Arctic surface temperatures during the Pliocene indicated by multiple independent proxies. Geology 38(7):603–606, https://doi.org/10.1130/G30815.1.

Bice, K.L., M.A. Arthur, and L. Marincovich Jr. 1996. Late Paleocene Arctic Ocean shallow marine temperatures from mollusc stable isotopes. Paleoceanography 11(3):241–249, https://doi.org/10.1029/96PA00813.

Brinkhuis, H., S. Schouten, M.E. Collinson, A. Sluijs, J.S. Sinninghe-Damsté, G.R. Dickens, M. Huber, T.M. Cronin, J. Onodera, K. Takahashi, and others. 2006. Episodic fresh surface waters in the early Eocene Arctic Ocean. Nature 441:606–609, https://doi.org/10.1038/nature04692.

Brozena, J.M., V.A., Childers, L.A., Lawver, L.M. Gahagan, R. Forsberg, J.L. Fileide, and O. Eldholm. 2003. New aerogeophysical study of the Eurasia Basin and Lomonosov Ridge: Implications for basin development. Geology 31:825–828, https://doi.org/10.1130/G19528.1.

Bruvoll, V., Y. Kristoffersen, B.J. Coakley and J.R. Hopper. 2010. Hemipelagic deposits on the Mendeleev and northwestern Alpha submarine Ridges in the Arctic Ocean: Acoustic stratigraphy, depositional environment and an inter-ridge correlation calibrated by the ACEX results. Marine Geophysical Researches 31:149–171, https://doi.org/10.1007/s11001-010-9094-9.

Coxall, H.K., and P.N. Pearson. 2007. The Eocene-Oligocene transition. Pp. 351–387 in Deep Time Perspectives on Climate Change: Marrying the Signal from Computer Models and Biological Proxies. M. Williams, A.M. Haywood, J.F. Gregory, and D.N. Schmidt, eds, Geological Society of London on behalf of The Micropalaeontological Society, Special Publication, London.

Cronin, T.M., L. Gemery, W.M. Briggs, M. Jakobsson, L. Polyak, and E.M. Brouwers. 2010. Quaternary sea-ice history in the Arctic Ocean based on new Ostracode sea-ice proxy. Quaternary Science Reviews 29:3,415–3,429, https://doi.org/10.1016/j.quascirev.2010.05.024.

Darby, D.A. 2008. Arctic perennial ice cover over the last 14 million years. Paleoceanography 23, PA1S07, https://doi.org/10.1029/2007PA001479.

Davies, A., A.E.S. Kemp, and J. Pike. 2009. Late Cretaceous seasonal ocean variability from the Arctic. Nature 460:254–258, https://doi.org/10.1038/nature08141.

Dove, D., B. Coakley, J. Hopper, Y. Kristoffersen, and HLY0503 Geophysics Team. 2010. Bathymetry, controlled source seismic and gravity observations of the Mendeleev ridge: Implications for ridge structure, origin, and regional tectonics. Geophysical Journal International 183(2):481–502, https://doi.org/10.1111/j.1365-246X.2010.04746.x.

Dyck, S., L.B. Tremblay, and A. de Vernal. 2010. Arctic sea-ice cover from the early Holocene: The role of atmospheric circulation patterns. Quaternary Science Reviews 29:3,457–3,467, https://doi.org/10.1016/j.quascirev.2010.05.008.

Eberle, J.J., H.C., Fricke, J.D. Humphrey, L. Hackett, M.G. Newbrey, and J.H. Hutchison. 2010. Seasonal variability in Arctic temperatures during early Eocene time. Earth and Planetary Science Letters 296(3–4):481–486, https://doi.org/10.1016/j.epsl.2010.06.005.

Eldrett, J.S., D.R. Greenwood, I.C. Harding, and M. Huber. 2009. Increased seasonality through the Eocene to Oligocene transition in northern high latitudes. Nature 459:969–973, https://doi.org/10.1038/nature08069.

Eldrett, J.S., I.C. Harding, P.A. Wilson, E. Butler, and A.P. Roberts. 2007. Continental ice in Greenland during the Eocene and Oligocene. Nature 446:176–179, https://doi.org/10.1038/nature05591.

Falcon-Lang, H.J., R.A. MacRae, and A.Z. Csank. 2004. Palaeoecology of late Cretaceous polar vegetation preserved in the Hansen Point volcanics, NW Ellesmere Island, Canada. Palaeogeography, Palaeoclimatology, Palaeoecology 212:45–64, https://doi.org/10.1016/S0031-0182(04)00303-7.

Funder, S., O. Bennike, J. Böcher, C. Israelson, K.S. Petersen, and L.A. Símonarson. 2001. Late Pliocene Greenland: The Kap København Formation in North Greenland. Bulletin of the Geological Society of Denmark 48:117–134.

Fyles, J.G., L.V. Hills, J.V. Mathews Jr., R.W. Barendregt, J. Baker, E. Irving, and H. Jette. 1994. Ballast Brook and Beaufort formations (Late Tertiary) on northern Banks Island. Arctic Canada Quaternary International 22/23:141–171.

Fyles, J.G., D.H. McNeil, J.V. Matthews, R.W. Barendregt, L. Marincovich, E. Brouwers, J. Bednarski, J. Brigham-Grette, L.E. Ovenden, K.G. Miller, and others. 1998. Geology of Hvitland Beds (Late Pliocene), White Point Lowland, Ellesmere Island, Northwest Territories. Geological Survey of Canada Bulletin 512, 35 pp.

Graham, A. 1999. Late Cretaceous and Cenozoic History of North American Vegetation. Oxford University Press, Oxford, UK, 370 pp.

Greenwood, D.R., J.F. Basinger, and R.Y. Smith. 2010. How wet was the Arctic Eocene rainforest? Precipitation estimates from Arctic Paleogene macrofloras. Geology 38:15–18, https://doi.org/10.1130/G30218.1.

Harland, M., J. Francis, S. Brentnall, and D. Beerling. 2007. Cretaceous (Albian-Aptian) conifer wood from Northern Hemisphere high latitudes: Forest composition and palaeoclimate. Review of Palaeobotany and Palynology 143:167–196, https://doi.org/10.1016/j.revpalbo.2006.07.005.

Harrison, J.C., U. Mayr, D.H. McNeil, A.R. Sweet, D.J. McIntyre, J.J. Eberle, C. Harington, J. Chalmers, G. Dam, and H.N. Hansen. 1999. Correlation of Cenozoic sequences of the Canadian Arctic region and Greenland: Implications for the tectonic history of northern North America. Bulletin of Canadian Petroleum Geology 47:223–254.

Hickey, L.J., K.R. Johnson, and M.R. Dawson. 1988. The stratigraphy, sedimentology and fossils of the Haughton Formation: A post-impact crater fill, Devon Islands, N.W.T., Canada. Meteoritics 23:221–231.

Hills, L.V., J.E. Klovan, and A.R. Sweet. 1974. Juglans eocinerea n. sp., Beaufort Formation (Tertiary), southwestern Banks Island. Canadian Journal of Botany 52:65–90, https://doi.org/10.1139/b74-011.

Holland, M.M., and C.M. Bitz. 2003. Polar amplification of climate change in coupled models. Climate Dynamics 21:221–232, https://doi.org/10.1007/s00382-003-0332-6.

Huber, M., and R. Caballero. 2011. The early Eocene equable climate problem revisited. Climate of the Past Discussions 7:241–304, https://doi.org/10.5194/cpd-7-241-2011.

IPCC (Intergovernmental Panel on Climate Change). 2007. Summary for policymakers. In Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. S. Solomon, D. Qin, M. Manning, Z. Chen, M. Marquis, K.B. Averyt, M. Tignor, and H.L. Miller, eds, Cambridge University Press, Cambridge and New York.

Jahren, A.H., and L.S.L. Sternberg. 2003. Humidity estimate for the middle Eocene Arctic rain forest. Geology 31(5):463–466, https://doi.org/10.1130/0091-7613(2003)031<0463:HEFTME>2.0.CO;2.

Jakobsson, M. 2002. Hypsometry and volume of the Arctic Ocean and its constituent seas. Geochemistry, Geophysics, Geosystems 3:1–18, https://doi.org/10.1029/2001GC000302.

Jakobsson, M., J. Backman, B. Rudels, J. Nycander, M. Frank, L. Mayer, W. Jokat, F. Sangiorgi, M. O’Regan, H. Brinkhuis, and others. 2007. The early Miocene onset of a ventilated circulation regimen in the Arctic Ocean. Nature 447:986–990, https://doi.org/10.1038/nature05924.

Jakobsson, M., A. Long, O. Ingolfsson, K.H. Kjaer, and R. Spielhagen. 2010a. New insights on Arctic Quaternary climate change variability from palaeo-records and numerical modelling. Quaternary Science Reviews 29:3,349–3,358, https://doi.org/10.1016/j.quascirev.2010.08.016.

Jakobsson, M., R. Macnab, L. Mayer, R. Anderson, M. Edwards, J. Hatzky, H.W. Schenke, and P. Johnson. 2008. An improved bathymetric portrayal of the Arctic Ocean: Implications for ocean modeling and geological, geophysical and oceanographic analyses. Geophysical Research Letters 35, L07602, https://doi.org/10.1029/2008GL033520.

Jakobsson, M., J. Nilsson, M. O’Regan, J. Backman, L. Löwemark, J.A. Dowdeswell, L. Mayer, L. Polyak, F. Colleoni, L. Anderson, and others. 2010b. An Arctic Ocean ice shelf during MIS 6 constrained by new geophysical and geological data. Quaternary Science Reviews 29:3,505–3,517, https://doi.org/10.1016/j.quascirev.2010.03.015.

Jenkyns, H.C., A. Forster, S. Schouten, and J.S. Sinninghe Damsté. 2004. High temperatures in the late Cretaceous Arctic Ocean. Nature 432:888–892, https://doi.org/10.1038/nature03143.

Knies, J., and C. Gaina. 2008. Middle Miocene ice sheet expansion in the Arctic: Views from the Barents Sea. Geochemistry, Geophysics, Geosystems 9(2), Q02015, https://doi.org/10.1029/2007GC001824.

Knies, J., J. Matthiessen, C. Vogt, J.S. Laberg, B.O. Hjelstuen, M. Smelror, E. Larsen, K. Andreassen, T. Eidvin, and T.O. Vorren. 2009. The Plio-Pleistocene glaciation of the Barents Sea Svalbard region: A new model based on revised chronostratigraphy. Quaternary Science Reviews 28:812–829, https://doi.org/10.1016/j.quascirev.2008.12.002.

Kristoffersen, Y. 1990. Eurasian Basin. Pp. 365–378 in The Arctic Ocean Region, Geology of North America, vol. L. A. Grantz, L. Johnson, and J.F. Sweeny, eds, Geological Society of America, Boulder, CO.

Krylov, A.A., I.A. Andreeva, C. Vogt, J. Backman, V.V. Krupskaya, G.E. Grikurov, K. Moran, and H. Shoji. 2008. A shift in heavy and clay mineral provenance indicates a middle Miocene onset of a perennial sea ice cover in the Arctic Ocean. Paleoceanography 23, PA1S06, https://doi.org/10.1029/2007PA001497.

Kürschner, W.M., Z. Kvacek, and D.L. Dilcher. 2008. The impact of Miocene atmospheric carbon dioxide fluctuations on climate and the evolution of terrestrial ecosystems. Proceedings of the National Academy of Sciences of the United States of America 105(2):449–453.

Laberg, J.S., K. Andreassen, J. Knies, T.O. Vorren, and M. Winsborrow. 2010. Late Pliocene-Pleistocene development of the Barents Sea ice sheet. Geology 38(2):107–110, https://doi.org/10.1130/G30193.1.

Lawver, L.A., A. Grantz, and L.M. Gahagan. 2002. Plate kinematic evolution of the present Arctic region since the Ordovician. Geological Society of America Special Paper 360:333–358.

Lunt, D.J., G.L. Foster, A.M. Haywood, and E.J. Stone. 2008. Late Pliocene Greenland glaciation controlled by a decline in atmospheric CO2 levels. Nature 454:1,102–1,105, https://doi.org/10.1038/nature07223.

Marincovich, L. Jr., and A.Y. Gladenkov. 2001. New evidence for the age of Bering Strait. Quaternary Science Reviews 20:329–335, https://doi.org/10.1016/S0277-3791(00)00113-X.

Matthiessen, J., J. Knies, C. Vogt, and R. Stein. 2009. Pliocene paleoceanography of the Arctic Ocean and subarctic seas. Philosophical Transactions of the Royal Society A 367:21–48, https://doi.org/10.1098/rsta.2008.0203.

McIver, E.E., and J.F. Basinger. 1999. Early Tertiary floral evolution in the Canadian High Arctic. Annals of the Missouri Botanical Garden 86:523–545, https://doi.org/10.2307/2666184.

Micheels, A., A. Brunch and V. Mosbrugger. 2009. Miocene climate modelling sensitivity experiments for different CO2 concentrations. Palaeontologia Electronica 12(2), 20 pp.

Miller, G.H., R.B. Alle, J. Brigham-Grette, J.J. Fitzpatrick, L. Polyak, M.C. Serreze, and J.W.C. White. 2010. Arctic amplification: Can the past constrain the future? Quaternary Science Reviews 29:1,779–1,790, https://doi.org/10.1016/j.quascirev.2010.02.008.

Moran, K., J. Backman, H. Brinkhuis, S.C. Clemens, T. Cronin, G.R. Dickens, F. Eynaud, J. Gattacceca, M. Jakobsson, R.W. Jordan, and others. 2006. The Cenozoic palaeoenvironment of the Arctic Ocean. Nature 441:601–605, https://doi.org/10.1038/nature04800.

Mudelsee, M., and M.E. Raymo. 2005. Slow dynamics of the Northern Hemisphere glaciation. Paleoceanography 20, PA4022, https://doi.org/10.1029/2005PA001153.

Nørgaard-Pedersen, N., R.F. Spielhagen, H. Erlenkeuser, P.M. Grootes, J. Heinemeier, and J. Knies. 2003. Arctic Ocean during the Last Glacial Maximum: Atlantic and polar domains of surface water mass distribution and ice cover. Paleoceanography 18:1–19, https://doi.org/10.1029/2002PA000781.

Ó Cofaigh, C., J. Taylor, J.A. Dowdeswell, and C.J. Pudsey. 2003. Palaeo-ice streams, trough mouth fans and high-latitude continental slope sedimentation. Boreas 32:37–55, https://doi.org/10.1080/03009480310001858.

Onodera, J., K. Takahashi, R.W. Jordan. 2008. Eocene silicoflagellate and ebridian paleoceanography in the central Arctic Ocean. Paleoceanography 23, PA1S15, https://doi.org/10.1029/2007PA001474.

Otto-Bliesner, B.L., E.C. Brady, and C. Shields. 2002. Late Cretaceous ocean: Coupled simulations with the National Center for Atmospheric Research Climate System Model. Journal of Geophysical Research 107(D2), 4019, https://doi.org/10.1029/2001JD000821.

Pagani, M., Z. Liu, J. LaRiviere, and A.C. Ravelo. 2010. High Earth-system climate sensitivity determined from Pliocene carbon dioxide concentrations. Nature Geoscience 3:27–30, https://doi.org/10.1038/ngeo724.

Pagani, M., J. Zachos, K.H. Freeman, S. Bohaty, and B. Tipple. 2005. Marked change in atmospheric carbon dioxide concentrations during the Oligocene. Science 309:600–603, https://doi.org/10.1126/science.1110063.

Pekar, S.F., and R.M. DeConto. 2006. High-resolution ice-volume estimates for the early Miocene: Evidence for a dynamic ice sheet in Antarctica. Paleogeography, Paleoclimatology, Paleoecology 231:101–109, https://doi.org/10.1016/j.palaeo.2005.07.027.

Perovich, D.K., J.A. Richter-Menge, K.F. Jones, and B. Light. 2007. Sunlight, water, and ice: Extreme Arctic sea ice melt during the summer of 2007. Geophysical Research Letters 35, L11501, https://doi.org/10.1029/2008GL034007.

Poirier, A., and C. Hillaire-Marcel. 2011. Improved Os-isotope stratigraphy of the Arctic Ocean. Geophysical Research Letters 36, L11602, https://doi.org/10.1029/2009GL037422.

Polyak, L., and M. Jakobsson. 2011. Quaternary sedimentation in the Arctic Ocean: Recent advances and further challenges. Oceanography 24(3):52–64, https://doi.org/10.5670/oceanog.2011.55.

Polyak, L., R.B. Alley, J.T. Andrews, J. Brigham-Grette, T.M. Cronin, D.A. Darby, A.S. Dyke, J.J. Fitzpatrick, S. Funder, and M. Holland. 2010. History of sea ice in the Arctic. Quaternary Science Reviews 29:1,757–1,778, https://doi.org/10.1016/j.quascirev.2010.02.010.

Polyakov, I.V., A. Beszczynska, E.C. Carmack, I.A. Dmitrenko, E. Fahrbach, I.E. Frolov, R. Gerdes, E. Hansen, J. Holfort, V.V. Ivanov, and others. 2005. One more step toward a warmer Arctic. Geophysical Research Letters 32(17):605–608, https://doi.org/10.1029/2005GL023740.

Robinson, M.M. 2009. New quantitative evidence of extreme warmth in the Pliocene Arctic. Stratigraphy 6(4):265–275.

Robinson, M.M, P.J. Valdes, A.M. Haywood, H.J. Dowsett, D.J. Hill, and S.M. Jones. In press. Bathymetric controls on Pliocene North Atlantic and Arctic sea surface temperature and deepwater production. Palaeogeography, Palaeoclimatology, Palaeoecology, https://doi.org/10.1016/j.palaeo.2011.01.004.

Sangiorgi, F., H.‐J. Brumsack, D.A. Willard, S. Schouten, C.E. Stickley, M. O’Regan, G.‐J. Reichart, J.S. Sinninghe Damsté, and H. Brinkhuis. 2008. A 26 million year gap in the central Arctic record at the Greenhouse-Icehouse transition: Looking for clues. Paleoceanography 23, PA1S04, https://doi.org/10.1029/2007PA001477.

Shevenell, A.E., J.P. Kennett, and D.W. Lea. 2004. Middle Miocene Southern Ocean cooling and Antarctic cryosphere expansion. Science 305:1,766–1,770, https://doi.org/10.1126/science.1100061.

Shimada, K., T. Kamoshida, M. Itoh, S. Nishino, E. Carmack, F. McLaughlin, S. Zimmermann, and A. Proshutinsky. 2006. Pacific Ocean inflow: Influence on catastrophic reduction of sea ice cover in the Arctic Ocean. Geophysical Research Letters 33, LR8605, https://doi.org/10.1029/2005GL025624.

Sluijs, A., S. Schouten, T.M. Donders, P.L. Schoon, U. Röhl, G-L. Reichart, F. Sangiorgi, J-H Kim, J.S. Sinninghe Damsté, and H. Brinkhuis. 2009. Warm and wet conditions in the Arctic region during Eocene Thermal Maximum 2. Nature Geoscience 2:777–780, https://doi.org/10.1038/ngeo668.

Sluijs, A., S. Schouten, M. Pagani, M. Woltering, H. Brinkhuis, J.S. Sinninghe Damsté, G.R. Dickens, M. Huber, G.-J. Reichart, R. Stein, and others. 2006. Subtropical Arctic Ocean temperatures during the Palaeocene/Eocene thermal maximum. Nature 441:610–613, https://doi.org/10.1038/nature04668.

Spicer, R.A., and A.B. Herman. 2010. The Late Cretaceous environment of the Arctic: A quantitative reassessment based on plant fossils. Paleogeography, Paleoclimatology, Paleoecology 295:423–442, https://doi.org/10.1016/j.palaeo.2010.02.025.

St. John, K. 2008. Cenozoic ice-rafting history of the central Arctic Ocean: Terrigenous sands on the Lomonosov Ridge. Paleoceanography 23, PA1S05, https://doi.org/10.1029/2007PA001483.

Stein, R. 2008. Arctic Ocean Sediments: Processes, Proxies, and Paleoenvironment. Elsevier, Amsterdam, 592 pp.

Stein, R., B. Boucsein, and H. Meyer. 2006. Anoxia and high primary production in the Paleogene central Arctic Ocean: First detailed records from the LR. Geophysical Research Letters 33, L18606, https://doi.org/10.1029/2006GL026776.

Steppuhn, A., A. Micheels, A.A. Bruch, D. Uhl, T. Utescher, and V. Mosbrugger. 2007. The sensitivity of ECHAM4/ML to a double CO2 scenario for the late Miocene and the comparison to terrestrial proxy data. Global and Planetary Change 57:189–212, https://doi.org/10.1016/j.gloplacha.2006.09.003.

Stickley, C., N. Koç, H-J. Brumsack, R. Jordan, and I. Suto. 2008. A siliceous microfossil view of Middle Eocene Arctic palaeoenvironments: A window of biosilica production and preservation. Paleoceanography 23, PA1S14, https://doi.org/10.1029/2007PA001485.

Stickley, C., K. St. John, N. Koç, R.W. Jordan, S. Passchier, R.B. Pearce, and L.E. Kearns. 2009. Evidence for middle Eocene Arctic sea ice from diatoms and ice-rafted debris. Nature 460:376–379, https://doi.org/10.1038/nature08163.

Stroeve, J., and W. Meier. 2010. Sea Ice Trends and Climatologies from SMMR and SSM/I, June to September 2010. National Snow and Ice Data Center, Boulder, CO, digital media.

Stroeve, J., M.M. Holland, W. Meier, T. Scambos, and M. Serreze. 2007. Arctic sea ice decline: Faster than forecast. Geophysical Research Letters 34, L09501, https://doi.org/10.1029/2007GL029703.

Tarduno, J.A., D.B. Brinkman, P.R. Renne, R.D. Cottrell, H. Scsher, and P. Castillo. 1998. Evidence for extreme climatic warmth from Late Cretaceous Arctic vertebrates. Science 282:2,241–2,244, https://doi.org/10.1126/science.282.5397.2241.

Tong, J.A., Y. You, R.D. Muller, and M. Seton. 2009. Climate model sensitivity to atmospheric CO2 concentrations for the middle Miocene. Global and Planetary Change 67:129–140, https://doi.org/10.1016/j.gloplacha.2009.02.001.

Torsvik, T.H., D. Carlos, J. Mosar, L.R.M. Cocks, and T. Malme. 2002. Global reconstructions and North Atlantic palaeogeography 400 Ma to recent. Pp. 18–39 in BATLAS: Mid Norway Plate Reconstructions Atlas with Global and Atlantic Perspectives. E.A. Eide, coordinator, Geological Survey of Norway.

Tripati, A., R.A. Eagle, A. Morton, J.A. Dowdeswell, K.L. Atkinson, Y. Bahé, C.F. Dawber, E. Khadun, R.M.H. Shaw, O. Shorttle, and L. Thanabalasundaram. 2008. Evidence for glaciation in the Northern Hemisphere back to 44 Ma from ice-rafted debris in the Greenland Sea. Earth and Planetary Science Letters 265:112–122, https://doi.org/10.1016/j.epsl.2007.09.045.

Tripati, A., J. Zachos, L. Marincovich Jr., and K. Bice. 2001. Late Paleocene Arctic coastal climate inferred from molluscan stable and radiogenic isotope ratios. Palaeogeography, Palaeoclimatology, Palaeoecology 170:101–113, https://doi.org/10.1016/S0031-0182(01)00230-9.

Verhoeven, K., S. Louwye, J. Eiríksson, and S. De Schepper. In press. A new age model for the Early Pliocene Tjörnes beds (Iceland) and its palaeoceanographic implications. Palaeogeography, Palaeoclimatology, Palaeoecology, https://doi.org/10.1016/j.palaeo.2011.04.001.

Wang, M., and J.E. Overland. 2009. A sea ice free summer Arctic within 30 years? Geophysical Research Letters 36, L07502, https://doi.org/10.1029/2009GL037820.

Weller, P., and R. Stein. 2008. Paleogene biomarker records from the central Arctic Ocean (IODP Expedition 302): Organic-carbon sources, anoxia, and sea-surface temperature. Paleoceanography 23, PA1S17, https://doi.org/10.1029/2007PA001472.

White, J.M., and T.A. Ager. 1994. Palynology, palaeoclimatology and correlation of middle Miocene beds from Porcupine River (locality 90-1), Alaska. Quaternary International 22/23:43–77, https://doi.org/10.1016/1040-6182(94)90006-X.

White, J.M., T.A. Ager, D.P. Adam, E.B. Leopold, G. Liu, H. Jette, and C.E. Schweger. 1997. An 18-million-year record of vegetation and climate change in northwestern Canada and Alaska: Tectonic and global climatic correlates. Palaeogeography, Palaeoclimatology, Palaeoecology 130:293–306, https://doi.org/10.1016/S0031-0182(96)00146-0.

Wilson, P.A., R.D. Norris, and M.J. Cooper. 2002. Testing the Cretaceous greenhouse hypothesis using glassy foraminiferal calcite from the core of the Turonian tropics on Demerara rise. Geology 30:607–610, https://doi.org/10.1130/0091-7613(2002)030<0607:TTCGHU>2.0.CO;2.

Williams, C.J., A.H. Johnson, B.A. LePage, D.R. Vann, and T. Sweda. 2003. Reconstruction of Tertiary Metasequoia forests. II. Structure, biomass, and productivity of Eocene floodplain forests in the Canadian Arctic. Paleobiology 29:271–292, https://doi.org/10.1666/0094-8373(2003)029<0271:ROTMFI>2.0.CO;2.

Williams, C.J., E.K. Mendell, J. Murphy, W.M. Court, A.H. Johnson, and S.L. Richter. 2008. Paleoenvironmental reconstruction of a Middle Miocene forest from the western Canadian Arctic. Palaeogeography, Palaeoclimatology, Palaeoecology 261:160–176, https://doi.org/10.1016/j.palaeo.2008.01.014.

Wolfe, J.A. 1994. An analysis of Neogene climates in Beringia. Palaeogeography, Palaeoclimatology, Palaeoecology 108:207–216, https://doi.org/10.1016/0031-0182(94)90234-8.

Zachos, J.C., G.R. Dickens, and R.E. Zeebe. 2008. An early Cenozoic perspective on greenhouse warming and carbon-cycle dynamics. Nature 451:279–283, https://doi.org/10.1038/nature06588.

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