Late quaternary environments in the arctic region
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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 l.jpg
LateQuaternary environments in the Arctic region


Late tertiary climatic decline in the arctic l.jpg
Late Tertiary climatic decline in the Arctic

from: White et al. (1997) Palaeo3 30, 293-306.



Rsl temperature sea ice conditions in the arctic ocean l.jpg
RSL - temperature - sea ice conditions in the Arctic Ocean

North Atlantic - Arctic Ocean water exchange

rates about 37% lower at LGM than at present



Bering sea beringia l.jpg
Bering Sea/Beringia

submerged

sill

(-48m)

exposed


The most recent submergence 10 11 000 cal yrs bp l.jpg
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 l.jpg
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)


Multiple migrations l.jpg
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



The mammoth steppe controversy l.jpg
The “mammoth-steppe” controversy

www.photostar-usa.com/photography/destination/Beringia/beringia.htm



Faunal composition of the mammoth steppe l.jpg
Faunal composition of the “Mammoth steppe” Macmillan

SIBERIA

ALASKA

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


Why steppe l.jpg
Why steppe? 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.


Why not tundra l.jpg
Why not tundra? Macmillan

“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 l.jpg
The pollen evidence: Macmillanpercent abundance of common plants

Data from: Elias et al. (1997) Nature 386, 60-63.


Central beringia palaeoenvironments l.jpg
Central Beringia palaeoenvironments Macmillan

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 l.jpg
Full-glacial upland tundra* Macmillan

*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 l.jpg
Tundra types in northern Alaska Macmillan

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


Iceworld wisconsinan glaciation20 l.jpg

H Macmillan

H

Iceworld: Wisconsinan glaciation

Is moist non-acidic tundra the modern equivalent of tundra-steppe? Was it sustained by loess deposition?

storm

paths


Climatic change in the holocene the driving forces at 60 n l.jpg
Climatic change in the Holocene: Macmillan the driving forces at 60°N

750 830


Late quaternary pollen record eastern beringia l.jpg
Late Quaternary pollen record -Eastern Beringia Macmillan

after: Cwynar (1982)


Holocene changes in vegetation eastern beringia l.jpg
Holocene changes in vegetation; eastern Beringia Macmillan

C. Alaska Yukon

warmercooler

drier?moister

summers

From: Grimm et al. (2001)


Slide24 l.jpg

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


Deglaciation of the laurentide ice sheet l.jpg
Deglaciation of the Laurentide Ice Sheet Macmillan

from: Hughes (1989)


Dated occurrences of bivalves baffin island l.jpg
Dated occurrences of bivalves: Baffin Island Macmillan

from: Kelly (1985) in Andrews, JT “Quaternary Environments, Eastern Canadian Arctic…”


Location of core ps21880 green dot and raffles o red dot l.jpg
Location of core PS21880 Macmillan(green dot) and RafflesO (red dot)


Relative abundance of sea ice diatoms length of sea ice season at ps21880 l.jpg
Relative abundance of sea-ice diatoms Macmillan(= length of sea-ice season?)at PS21880

“Hypsithermal” “Neoglacial”

From: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.


The diatom record from raffles so east greenland l.jpg
The diatom record from Raffles So, East Greenland Macmillan

“Hypsithermal” “Neo-

glacial”

from: Cremer et al., (2001)

J. Paleolimnology, 26, 67-87


Late quaternary sst greenland iceland norway seas l.jpg
Late Quaternary SST, Macmillan Greenland-Iceland-Norway Seas

from: Koc et al. (1993) Quat. Sci. Rev., 12, 115-140.


Location of core gpc 2208 l.jpg
Location of core GPC-2208 Macmillan

N Pole

2208

from: Gard (1993)

Geology, 21, 227-230.


Coccolithophores in core gpc 2208 l.jpg
Coccolithophores in core GPC-2208 Macmillan

early-mid

Holocene?

from: Gard (1993) Geology, 21, 227-230.


The pollen record from n norway l.jpg
The pollen record from N. Norway Macmillan

from: Alm (1993)Boreas 22:171-188





Late holocene climate change alaska l.jpg

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.


Environmental change in the arctic ad1600 2000 l.jpg
Environmental change in the Arctic, AD1600-2000 500 0

from: Overpeck et al., (1997)

Science 278, 1251-1256


Slide40 l.jpg

from: Overpeck et al., (1997) 500 0Science 278, 1251-1256


Late quaternary environments in antarctica l.jpg
Late 500 0Quaternary environments in Antarctica



Climatic change in the holocene the driving forces at 60 s l.jpg
Climatic change in the Holocene: 500 0the driving forces at 60°S

S

830 750


Holocene relative sea level change in the vestfold hills antarctica l.jpg
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.


Slide45 l.jpg

low penguin Antarctica*

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 l.jpg
Recent (post-AD 1980) changes in Antarctic lakes Antarctica*

From: Quayle et al., (2002) Science, 295, 645.


Responses to c20th climate change in antarctica l.jpg
Responses to C20th climate change in Antarctica 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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