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Podocarp
/hardwood
Montane-subalpine
trees and shrubs
Wetland
and aquatics
Beech
Herbs
Age (kyr)
*
14
C
Luminescence
0
100
1
200
*11.0
300
*14.4
*17.3
2
Kkt
400
3
500
48-75
4
600
5a
5b
5c
5d
700
800
5e
127
9
00
6
1000
50
100
40
40
80
40
40
Scale interval = 5% dryland pollen
40
40
40
80
40
40 40
80
Fibrous peat
Brown organic silt
Wood
Light-brown organic silty sand
Compact sedge peat
Kawakawa tephra (Kkt) 26.5 kyr
Blue/grey laminated silt
Coarse sand/gravel
Blue/grey silty sand
Fig. 4.8
SummarypollendiagramfromOkaritoPakihi,NewZealand.Notethatthetimescalegetsmorecondensedas
onetravelsthefurtherintothepast.Also,thecurrentinterglacial(Holocene),LGMandearlyglacialvegetation
typesshowupclearly.Thelastinterglacialvegetationdoesnot,andlocalinsolationwaslowatthattime.
ReproducedwithpermissionfromVandergoesetal.(2005).kyr,thousandyears.
The atmospheric gas composition of bubbles of northern and southern hemisphere
ice cores track more exactly, which is not surprising given that global mixing of the
planet's atmosphere takes a little over a year or two. Figure 4.6b is a low-resolution
portrayal of methane from both hemispheres over the entirety of the past glacial-
interglacial cycle and demonstrates synchrony.
The cores clearly demonstrate that glacials and interglacials are not just hemi-
spheric events but planet-wide in nature. Further, they show that some trends and
features within the glacial are also global (even if hemispherically they are not
exactly in phase).
The core records also demonstrate the broad structure of the glacial and inter-
glacial cycle. For example, the LGM occurred at the end of the glacial as opposed
to the middle, which would be likely if glacial-interglacial temperature cycles were
uniformly sinusoidal. However, cores have shown that other features that are pro-
nounced in one hemisphere are only weakly reflected in the other. The end-glacial
hiccup return to glacial conditions (the Allerød, Bølling and Younger Dryas; see
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