Geoscience Reference
In-Depth Information
Holocene
YD B/A
0.3
0.2
0.1
11,600
years B.P
2
1
0
-1
0.14
0.1
0.2
Worldwide
glacial
expansions
0
0.04
Southern Hemisphere
Synthesis of
proxy records
North America
Europe and Greenland
Cockburn moraine advance
0.02
YD event-GISP2
0
0.2
0
2000
4000 6000
Years B.P.
8000
10,000 12,000
0.04
0.1
0
2000
4000
6000
8000
10,000
~ 14 C years B.P.
0.02
14
6
1
-1
520
500
480
-21
A
Penny
P95
P96
24
-26
Agassiz
22
100
20
Agassiz melt
-30
0
18
0
40
B
-32
16
40
30
20
Penny
ssNA
10
8
20
0
0
2000
4000
6000
8000
10,000 12,000
GISP2
ssNA
8 0
Years B.P (2000 A.D.)
2
4
6
Thousands of years before 2000 A.D.
0
2000
4000
6000
8000
10,000
~ 14 C years B.P.
0 250 500
750
1000
1250
1500
1673
Figure 6.3 Time series of Holocene glaciochemical records and the first empirical orthogonal function (EOF1) derived from
the GISP2 ice core (top portion of figure on left) showing the cyclicity of periods dominated by cool temperatures, overall
aridity and vigorous circulation patterns during the Holocene (filled sections of curves above mean trend line). ss refers to
a sea salt origin; nss refers to a non-sea salt origin. The bottom part of the figure on left shows the relationship of these
parameters to insolation, sea level and land ice volume. The upper-right figure shows the relationship between these cold
periods (as noted by the EOF1 time series) and periods of known alpine glacier advances and other proxy records of cooler
climatic conditions. The lower-right shows the overall declining temperature record from the Penny Ice Cap 18 O record
and the Agassiz Ice Cap melt record (A). (B) shows the sea salt Na þ time series for the GISP2 and Penny ice cores. Note the
increase in the GISP2 sea salt Na þ record during the last few centuries of the record (i.e. Little Ice Age) compared to the
decrease in the Penny Ice Cap sea salt Na þ record over the same time period. (From O'Brien et al. 1995 ; Fisher et al. 1998
and Koerner and Fisher 1990 )
 
 
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