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Late
Quaternary
environments
in the Arctic
region
Late Tertiary climatic decline
in the Arctic
from: White et al. (1997) Palaeo3 30, 293-306.
The North
Polar
region:
dots are
pollen
analysis
sites
RSL - temperature - sea ice
conditions in the Arctic Ocean
North Atlantic - Arctic Ocean water exchange
rates about 37% lower at LGM than at present
Iceworld: Wisconsinan glaciation
Bering Sea/Beringia
submerged
exposed
sill
(-48m)
The most recent submergence:
~10 - 11 000 cal. yrs BP
submerged
exposed
Eustatic sea-level curve from: Lambeck & Chappell (2001) Science 292, 679-
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
(and humans)
Camels
Horse
Multiple migrations
Ma BP
ka BP
Mammoths
0
M.
0.3 primigenius
0
M.
columbi
0.6
0.9
1.2
Bison
B. bison
20
B.
antiquus
40
60
M.
trogontheri
1.5
100
1.8
120
M.
2.0 meridionalis
Asia
?
80
140
Beringia
land
B.
priscus
Asia
N America
water
?
Beringia
ice
N America
Beringia: glacial refuge
The “mammoth-steppe”
controversy
www.photostar-usa.com/photography/destination/Beringia/beringia.htm
adapted from: Lister,A. and Bahn, P. (1994) “Mammoths”, Macmillan
Faunal composition of the
“Mammoth steppe”
SIBERIA
ALASKA
from: Lister,A. and Bahn, P. (1994) “Mammoths”, Macmillan
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.
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
The pollen
evidence:
percent
abundance
of
common
plants
Data from: Elias et al. (1997) Nature 386, 60-63.
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.
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.
Tundra
types in
northern
Alaska
Moist acidic tundra
Moist 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
Iceworld: Wisconsinan glaciation
Is moist nonacidic tundra
the modern
equivalent of
tundra-steppe?
Was it sustained
by loess
deposition?
H
H
storm
paths
Climatic change in the Holocene:
the driving forces at 60°N
750
830
after: Cwynar (1982)
Late Quaternary pollen
record -Eastern Beringia
Holocene changes in
vegetation; eastern Beringia
Yukon
warmer cooler
drier? moister
summers
C. Alaska
From: Grimm et al. (2001)
from: Short et al. (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”
Deglaciation of the Laurentide Ice Sheet
from: Hughes (1989)
Dated occurrences of
bivalves: Baffin Island
from: Kelly (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”
Location
of core
PS21880
(green dot)
and
Raffles
O
(red dot)
(= length of seaice season?)
at PS21880
From: Koc et al. (1993)
Quat. Sci. Rev., 12, 115-140.
“Neoglacial”
“Hypsithermal”
Relative
abundance of
sea-ice diatoms
from: Cremer et al., (2001)
J. Paleolimnology, 26, 67-87
“Neoglacial”
“Hypsithermal”
The diatom
record
from
Raffles So,
East
Greenland
Late Quaternary SST,
Greenland-Iceland-Norway Seas
from: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.
Location
of core
GPC-2208
from: Gard (1993)
Geology, 21, 227-230.
N Pole
2208
Coccolithophores in core GPC-2208
early-mid
Holocene?
from: Gard (1993) Geology, 21, 227-230.
The pollen record from N. Norway
from: Alm (1993) Boreas 22:171-188
Late Quaternary climate change in
the Arctic from pollen records
from: CAPE Project
from: CAPE Project
Late Holocene climate change, Alaska
Glacial advances and retreats; Gulf of Alaska*
Lake geochemistry; Alaska Range**
no data
2500
warm
2000
cool
1500
1000
years BP
500
0
*Wiles et al., (2001) Quat. Sci. Rev. 20, 449-461; ** Hu et al., (2001) Proc. Nat. Acad. Sci.
Environmental
change in the
Arctic,
AD1600-2000
from: Overpeck et al., (1997)
Science 278, 1251-1256
from: Overpeck et al., (1997) Science 278, 1251-1256
Late
Quaternary
environments
in Antarctica
The Holocene climatic
optimum in Antarctica
Climatic change in the Holocene:
the driving forces at 60°S
830
S
750
Elevation (m, asl)
Holocene relative sea-level change
in the Vestfold Hills, Antarctica*
+12
+8
RSL
+4
Climatic
optimum
0
10
outer shelf
deglaciated
8
6
ka, BP
4
2
0
inner shelf
and nearshore
areas deglaciated
*from: Zwartz et al., (1998) Earth and Planetary Science Letters, 155, 131-145.
low penguin
population
Environmental change in Antarctica
(Ardley Peninsula) based on
penguin droppings
Inferred temperature
from: Sun et al., (2000) Nature, 407, 858.
Recent (post-AD 1980)
changes in Antarctic lakes
From: Quayle et al., (2002) Science, 295, 645.
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