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Late Quaternary environments in the Arctic region

Late Quaternary environments in the Arctic region. Late Tertiary climatic decline in the Arctic. from: White et al. (1997) Palaeo 3 30, 293-306. The North Polar region: dots are pollen analysis sites . RSL - temperature - sea ice conditions in the Arctic Ocean.

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Late Quaternary environments in the Arctic region

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  1. LateQuaternary environments in the Arctic region

  2. Late Tertiary climatic decline in the Arctic from: White et al. (1997) Palaeo3 30, 293-306.

  3. The North Polar region: dots are pollen analysis sites

  4. RSL - temperature - sea ice conditions in the Arctic Ocean North Atlantic - Arctic Ocean water exchange rates about 37% lower at LGM than at present

  5. Iceworld: Wisconsinan glaciation

  6. Bering Sea/Beringia submerged sill (-48m) exposed

  7. The most recent submergence: ~10 - 11 000 cal. yrs BP submerged exposed Eustatic sea-level curve from: Lambeck & Chappell (2001) Science 292, 679-

  8. Trans-Beringia mammal migrations during the Quaternary Beaver Lynx Snow & mountain sheep Moose Elk Bears Wolverine Wolf Arctic fox Arctic hare Bison Mountain goat Coyote Kit fox Camels Horse (and humans)

  9. Multiple migrations Ma BP ka BP Mammoths Bison 0 0.3 0.6 0.9 1.2 1.5 1.8 2.0 0 20 40 60 80 100 120 140 B. bison M. primigenius M. columbi B. antiquus ? M. trogontheri M. meridionalis B. priscus ? Asia Beringia N America Asia Beringia N America land water ice

  10. Beringia: glacial refuge

  11. The “mammoth-steppe” controversy www.photostar-usa.com/photography/destination/Beringia/beringia.htm

  12. adapted from: Lister,A. and Bahn, P. (1994) “Mammoths”, Macmillan

  13. Faunal composition of the “Mammoth steppe” SIBERIA ALASKA from: Lister,A. and Bahn, P. (1994) “Mammoths”, Macmillan

  14. Why steppe? Dale Guthrie (U. Alaska) argued* that the diverse array of grazers that comprised the Late Pleistocene megafauna of Beringia, which included the mammoth, wooly rhinoceros, saiga antelope, steppe bison, and Chersky horse, could have been supported only by arid, grass- and forb-dominated ecosystems, not by tundra, which today supports only caribou and muskoxen. Bison and saiga antelope in particular were considered to indicators of the ‘steppe-like’ nature of the plant community. * See article by Guthrie in Hopkins et al., (1982) “Palaeoecology of Beringia”, Academic Press.

  15. Why not tundra? “The tundra and boreal landscape is not simply a product of average annual rainfall and degree days. Vegetation itself affects soil character. The largely toxic insulating plant mat, shielded from high evaporation, promotes permafrost, or at least very cool soils, and limits available nutrients.This, in turn favors the same plants that created those soil conditions. The cycle propels itself; conservative plants on low-nutrient soils must defend themselves against herbivory by large mammals. This largely toxic vegetation limits the species diversity and biomass of the large mammal community”. Guthrie, R.D. (1990) "Frozen Fauna of the Mammoth Steppe: The Story of Blue Babe”, Chicago University Press, p. 207

  16. The pollen evidence:percent abundance of common plants Data from: Elias et al. (1997) Nature 386, 60-63.

  17. Central Beringia palaeoenvironments Late Glacial: birch-heath-graminoid tundra with small ponds; slightly warmer than PD at 11ka BP; mesic tundra. LGM: birch-graminoid tundra with small ponds; arctic climate, drier than late glacial; no steppe-tundra elements. >40 ka BP: birch-heath-graminoid tundra with no steppe elements, shrubs not important. from: Elias et al. (1997) Nature 386, 60-63.

  18. Full-glacial upland tundra* *plants recorded from a buried [21.5 cal. yr BP] tundra surface blanketed by 1m of tephra in the Seward Peninsula. from: Goethchus and Birks (2001) Quat Sci. Rev., 20, 135-147.

  19. Tundra types in northern Alaska Moist acidic tundraMoist nonacidic tundra ~x2 plant diversity; 10x extractable Ca; higher soil pH; O layer 50% as thick; 30% deeper active layer From: Walker et al., (2001) Quat. Sci. Rev., 20, 149-163

  20. H H Iceworld: Wisconsinan glaciation Is moist non-acidic tundra the modern equivalent of tundra-steppe? Was it sustained by loess deposition? storm paths

  21. Climatic change in the Holocene: the driving forces at 60°N 750 830

  22. Late Quaternary pollen record -Eastern Beringia after: Cwynar (1982)

  23. Holocene changes in vegetation; eastern Beringia C. Alaska Yukon warmercooler drier?moister summers From: Grimm et al. (2001)

  24. from: Short et al. (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”

  25. Deglaciation of the Laurentide Ice Sheet from: Hughes (1989)

  26. Dated occurrences of bivalves: Baffin Island from: Kelly (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”

  27. Location of core PS21880(green dot) and RafflesO (red dot)

  28. Relative abundance of sea-ice diatoms (= length of sea-ice season?)at PS21880 “Hypsithermal” “Neoglacial” From: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.

  29. The diatom record from Raffles So, East Greenland “Hypsithermal” “Neo- glacial” from: Cremer et al., (2001) J. Paleolimnology, 26, 67-87

  30. Late Quaternary SST, Greenland-Iceland-Norway Seas from: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.

  31. Location of core GPC-2208 N Pole 2208 from: Gard (1993) Geology, 21, 227-230.

  32. Coccolithophores in core GPC-2208 early-mid Holocene? from: Gard (1993) Geology, 21, 227-230.

  33. The pollen record from N. Norway from: Alm (1993)Boreas 22:171-188

  34. Late Quaternary climate change in the Arctic from pollen records

  35. from: CAPE Project

  36. from: CAPE Project

  37. 2500 2000 1500 1000 500 0 Late Holocene climate change, Alaska Glacial advances and retreats; Gulf of Alaska* Lake geochemistry; Alaska Range** warm cool no data years BP *Wiles et al., (2001) Quat. Sci. Rev. 20, 449-461; ** Hu et al., (2001) Proc. Nat. Acad. Sci.

  38. Environmental change in the Arctic, AD1600-2000 from: Overpeck et al., (1997) Science 278, 1251-1256

  39. from: Overpeck et al., (1997) Science 278, 1251-1256

  40. LateQuaternary environments in Antarctica

  41. The Holocene climatic optimum in Antarctica

  42. Climatic change in the Holocene: the driving forces at 60°S S 830 750

  43. Holocene relative sea-level change in the Vestfold Hills, Antarctica* +12 +8 +4 0 RSL Elevation (m, asl) Climatic optimum 10 8 6 4 2 0 ka, BP inner shelf and nearshore areas deglaciated outer shelf deglaciated *from: Zwartz et al., (1998) Earth and Planetary Science Letters, 155, 131-145.

  44. low penguin population Environmental change in Antarctica (Ardley Peninsula) based on penguin droppings Inferred temperature from: Sun et al., (2000) Nature, 407, 858.

  45. Recent (post-AD 1980) changes in Antarctic lakes From: Quayle et al., (2002) Science, 295, 645.

  46. Responses to C20th climate change in Antarctica • Ice shelf disintegration (e.g. N. Larsen & Wordie Shelf); • Summer sea-ice area has declined by >25% • Rapid spread of flowering plants (e.g. Antarctic hairgrass has expanded its range 25-fold since 1964) • New lichen species colonizing recently deglaciated areas

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