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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from: White et al. (1997) Palaeo3 30, 293-306.
North Atlantic - Arctic Ocean water exchange
rates about 37% lower at LGM than at present
Eustatic sea-level curve from: Lambeck & Chappell (2001) Science 292, 679-
Snow & mountain sheep
Asia Beringia N America
Asia Beringia N America
land water ice
adapted from: Lister,A. and Bahn, P. (1994) “Mammoths”, Macmillan
from: Lister,A. and Bahn, P. (1994) “Mammoths”, Macmillan
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.
“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
Data from: Elias et al. (1997) Nature 386, 60-63.
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.
*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.
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
Is moist non-acidic tundra the modern equivalent of tundra-steppe? Was it sustained by loess deposition?
after: Cwynar (1982)
C. Alaska Yukon
From: Grimm et al. (2001)
from: Short et al. (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”
from: Hughes (1989)
from: Kelly (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”
From: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.
from: Cremer et al., (2001)
J. Paleolimnology, 26, 67-87
from: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.
from: Gard (1993)
Geology, 21, 227-230.
from: Gard (1993) Geology, 21, 227-230.
from: Alm (1993)Boreas 22:171-188
from: CAPE Project
from: CAPE Project
2500 2000 1500 1000 500 0
Glacial advances and retreats; Gulf of Alaska*
Lake geochemistry; Alaska Range**
*Wiles et al., (2001) Quat. Sci. Rev. 20, 449-461; ** Hu et al., (2001) Proc. Nat. Acad. Sci.
from: Overpeck et al., (1997)
Science 278, 1251-1256
from: Overpeck et al., (1997) Science 278, 1251-1256
Elevation (m, asl)
10 8 6 4 2 0
*from: Zwartz et al., (1998) Earth and Planetary Science Letters, 155, 131-145.
Environmental change in Antarctica
(Ardley Peninsula) based on
from: Sun et al., (2000) Nature, 407, 858.
From: Quayle et al., (2002) Science, 295, 645.