Latest Pleistocene and Holocene glacier fluctuations in western Canada |
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| Authors: | Brian Menounos Gerald Osborn John J Clague Brian H Luckman |
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| Institution: | 1. Natural Resources and Environmental Studies Institute and Geography Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia V2N 4Z9, Canada;2. Department of Geoscience, University of Calgary, Calgary, Alberta T2N 1N4, Canada;3. Department of Earth Sciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada;4. Department of Geography, University of Western Ontario, London, Ontario N6A 5C2, Canada;1. Lamont-Doherty Earth Observatory of Columbia University, Palisades, NY 10964, USA;2. Department of Geology, University at Buffalo, Buffalo, NY 14260, USA;1. Department of Geography, Durham University, Durham, DH1 3LE, UK;2. Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John''s, Newfoundland, A1B 3X7, Canada;3. Department of Earth, Atmospheric and Planetary Sciences, Purdue University, West Lafayette, 47907-2051, IN, USA;4. Department of Physical Geography, and Bolin Centre for Climate Research, Stockholm University, 106 91 Stockholm, Sweden;5. United States Geological Survey, 12201 Sunrise Valley Drive, VA 20192, USA;6. Department of Environmental Sciences, MS 604, University of Toledo, Toledo, OH 43606-3390, USA;7. Department of Geological Sciences, Stockholm University, 106 91 Stockholm, Sweden;8. British Antarctic Survey, Madingley Road, Cambridge, CB3 0ET, UK;9. Department of Earth Science, University of Bergen, and Bjerknes Centre for Climate Research, 5007 Bergen, Norway;10. Department of Geography, University of Sheffield, Sheffield, S10 2TN, UK;11. Department of Geography, University of Sussex, Brighton, BN1 9QJ, UK;12. The University Centre in Svalbard (UNIS), 9171 Longyearbyen, Norway;13. Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario, M5S 1A7, Canada;14. Lamont Doherty Earth Observatory, Palisades, NY 10964, USA;15. NASA/Goddard Institute for Space Studies, 2880 Broadway, New York, NY 10025, USA;p. Geological Survey of Canada Atlantic, Bedford Institute of Oceanography, Dartmouth (Nova Scotia), B2Y 4A2, Canada;q. Institute of Earth and Environmental Sciences – Geology, University of Freiburg, Albertstr. 23b, 79104 Freiburg, Germany;r. Faculty of Earth and Life Sciences, Vrije University Amsterdam, Amsterdam, Netherlands;s. Laboratoire des Sciences du Climat et de l''Environnement (LSCE), CEA/CNRS-INSU/UVSQ, Gif-sur-Yvette Cedex, France;t. Department of Geological Sciences, University of Manitoba, Winnipeg, R3T 2N2, Canada;1. Geography Program and Natural Resources and Environmental Studies Institute, University of Northern British Columbia, 3333 University Way, Prince George, BC, V2N 4Z9, Canada;2. Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, BC, V5A 1S6, Canada;3. Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2207 Main Mall, Vancouver, BC, V6T 1Z4, Canada;4. College of Earth, Ocean, and Atmospheric Sciences, 104 COAS Admin Bldg., Corvallis, OR 97331, USA;5. Department of Geosciences, University of Calgary, 844 Campus Place Northwest, Calgary, AB, T2N 1N4, Canada;1. School of Earth Sciences & Environmental Sustainability, Northern Arizona University, Flagstaff, AZ 86011, USA;2. Department of Earth & Planetary Sciences, Northwestern University, Evanston, IL 60208, USA;3. School of Geography, Politics & Sociology, Newcastle University, NE1 7RU, UK;4. Institute for Liberal Arts & Interdisciplinary Studies, Emerson College, Boston, MA 02116, USA;5. Joint Institute for the Study of the Atmosphere & Ocean, University of Washington, Seattle, WA 98105, USA;6. School of Integrative Biology, University of Illinois, Urbana, IL 61801, USA;7. Department of Geography, University of Ottawa, Ottawa, ON K1N 6N5, Canada;8. Department of Plant Biology and Department of Geology, University of Illinois, Urbana, IL 61801, USA;9. Eastern Geology & Paleoclimate Science Center, U.S. Geological Survey, Reston, VA 20192, USA;10. Department of Earth & Environmental Sciences, Lehigh University, Bethlehem, PA 18015, USA;11. Geology Department, Mount Holyoke College, South Hadley, MA 01075, USA;12. Water & Environmental Research Center, School of Fisheries & Ocean Sciences, University of Alaska Fairbanks, Fairbanks, AK 99775, USA;1. Department of Geology, University at Buffalo, Buffalo, NY, USA;2. School of Earth Sciences & Environmental Sustainability, Northern Arizona University, Flagstaff, AZ, USA;3. Dept of Earth and Planetary Sciences, Northwestern University, Evanston, IL, 60208, USA;4. Geological Survey of Denmark and Greenland, Copenhagen, Denmark;5. Department of Geosciences, University of Massachusetts, Amherst, MA, 01003, USA;6. Centre de recherche en géochimie et géodynamique (Geotop), Université du Québec à Montréal, Montréal, QC, Canada;7. Department of Geology, University of Ottawa, Ottawa, ON, K1N6N5, Canada;8. Centre Eau Terre Environnement, Institut national de la recherche scientifique, Québec, Qc G1K 9A9, Canada;9. GEOTOP Research Center, Montréal, Qc H3C 3P8, Canada;10. Department of Geography, Environment and Geomatics, University of Ottawa, Ottawa, ON, K1N6N5, Canada;11. Institute of Arctic and Alpine Research, University of Colorado, Boulder, USA;12. Department of Geological Sciences and Institute of Arctic and Alpine Research, University of Colorado, Boulder, USA;13. Institute of Geology and Mineralogy, University of Cologne, Köln, Germany |
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| Abstract: | We summarize evidence of the latest Pleistocene and Holocene glacier fluctuations in the Canadian Cordillera. Our review focuses primarily on studies completed after 1988, when the first comprehensive review of such evidence was published. The Cordilleran ice sheet reached its maximum extent about 16 ka and then rapidly decayed. Some lobes of the ice sheet, valley glaciers, and cirque glaciers advanced one or more times between 15 and 11 ka. By 11 ka, or soon thereafter, glacier cover in the Cordillera was no more extensive than at the end of the 20th century. Glaciers were least extensive between 11 and 7 ka. A general expansion of glaciers began as early as 8.4 ka when glaciers overrode forests in the southern Coast Mountains; it culminated with the climactic advances of the Little Ice Age. Holocene glacier expansion was not continuous, but rather was punctuated by advances and retreats on a variety of timescales. Radiocarbon ages of wood collected from glacier forefields reveal six major periods of glacier advance: 8.59–8.18, 7.36–6.45, 4.40–3.97, 3.54–2.77, 1.71–1.30 ka, and the past millennium. Tree-ring and lichenometric dating shows that glaciers began their Little Ice Age advances as early as the 11th century and reached their maximum Holocene positions during the early 18th or mid-19th century. Our data confirm a previously suggested pattern of episodic but successively greater Holocene glacier expansion from the early Holocene to the climactic advances of the Little Ice Age, presumably driven by decreasing summer insolation throughout the Holocene. Proxy climate records indicate that glaciers advanced during the Little Ice Age in response to cold conditions that coincided with times of sunspot minima. Priority research required to further advance our understanding of late Pleistocene and Holocene glaciation in western Canada includes constraining the age of late Pleistocene moraines in northern British Columbia and Yukon Territory, expanding the use of cosmogenic surface exposure dating techniques, using multi-proxy paleoclimate approaches, and directing more of the research effort to the northern Canadian Cordillera. |
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