Absolute chronology of Late Quaternary
environmental change on western Svalbard
Jon Y. Landvik1, Helena Alexanderson1,2, Heidi T. Ryen1,
3
2
2
Anatoly Molodkov , Jan-Pieter Buylaert and Andrew S. Murray
1
Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, Norway; [email protected]
2
Nordic Laboratory for Luminescence Dating, Aarhus University, Risø DTU, Denmark
3
Research Laboratory for Quaternary Geochronology, Institute of Geology, Tallinn University of Technology, Estonia
Palaeoclimatologic scope
Environmental changes in the European High Arctic
during the last interglacial/glacial cycle were the result
of the delicate interplay between ocean circulation and
ice sheets. Age control on palaeoceanographic
changes have improved significantly over the last few
years; the challenge now is to provide better dating of
associated events reconstructed from the shallow
marine and terrestrial sedimentary records.
Kongsfjordhallet
Tønsneset
Kvadehuksletta
Stuphallet
We have a good relative chronology from litho- and
morphostratigraphy and some idea of the absolute
14
ages from the few available dates ( C, TL, IRSL, U/Th,
amino acid ratios).
Kjærsvika
Site 15
Our new absolute chronology is based on a
14
combination of OSL-, ESR- and C-dating of sediments
and fossils, and cosmogenic exposure dating of glacial
erratics.
Sites
We are investigating several sites in the
Kongsfjorden area, NW Svalbard, and present
results from three of those here: Site 15,
Kvadehuksletta and Tønsneset.
Conclusions so far
Challenges
¨ OSL-samples have good luminescence characteristics and
¨ Resolve differences between OSL- and ESR chronologies
¨ Correlation between sites
¨ Refining the age estimates for precise correlation to the marine
preliminary results are in stratigraphic order and largely
consistent with previous chronologies.
¨ The first ESR-ages are in most cases significantly younger
than corresponding OSL-ages and previous age estimates.
chronology
OSL dating
Kvadehuksletta: Sea-level change
Quartz grains (180-250 µm) in large aliquots have been
measured using SAR-protocols and Risø TL/OSL-readers.
Preheat and cutheat temperatures of 220° and 180°,
respectively, were used for all samples except young ones
(081341-43; 180°/160°) and 081354-55 from Kvadehuksletta
(260°/240°). Samples from the north side of the Kongsfjorden
suffer from some feldspar contamination and were measured
with post-IR blue OSL, all others with blue only.
The Kvadehuksletta plain is covered by raised beach
sediments, assumed to have been deposited during three
separate periods with high relative sea level sometime
between 10 and 260 ka.
Fossils
OSL (ka)
ESR (ka)
99
19
F
IR orm
SL a
n
Lithology
M
am ille
in r e
o ta
ac l.
id 19
zo 82
na
tio
m
a.s
U .l.
nit
n
Site 15: Constraining glaciations
The coastal cliffs at 'Site 15’ contain sediments laid down during
at least three glaciations and subsequent periods of high
relative sea level.
19
Glaciation
A
18
Holocene
36±3
90±5
Amino acid zones
(Forman & Miller 1984)
A
<12 ka
B
60-160 ka
C
130-290 ka
W
E
~80 m
a.s.l.
30
Luminescence characteristics
17
The OSL-signals from quartz are bright and characterised by a
fast component. Dose recovery and recycling ratios are close
to one, and recuperation is low.
28±2
?
?
14
13
Glaciation
12
11
10
138±13
123±8
117±8
164±14
9
58±7
C
125±10 ka
0
140±20 ka
15
8
7
6
5
25
6000
20
4000
2000
0
?
170
340
Dose (Gy)
510
0
?
?
15
10
~4 km
10
20
30
Time (s)
40
0
0.1
0.4
0.7
1
1.3
Measured/given dose
Dose recovery data.
4
174±11
Modern and historical analogues
188±12
3
D
>160 ka
10
2
1
0
Clay
Silt
Sand
G
ra
ve
l
Glaciation
243±18
172±13
185±15
159±13
198±46
Boulders
silty till
glaciomarine clay
marine shoreface sand
fan gravel
marine beachface gravel
beach gravel
Composite log from SIte 15 with OSL- and ESR-dates and other age
information. Ages in grey are preliminary (not all measurements
finished) and ’?’ are still pending.
The marine sediments appear to be well zeroed. Modern beach
sediments give 0.3 Gy, while a beach ridge at Tønsneset,
related to an ongoing transgression that started <5000 years
ago, gives OSL-ages of 0.7-1.8 ka.
ESR dating
The mollusc shells used for ESR-dating are of the species Mya
truncata, Hiatella arctica and Astarte sp. Generally the shells
were small and thin, which complicated analyses, but they were
whole and in some cases paired.
200
RLQG 376-088
ESR-data
RLQG 376-088
RLQG 377-088
RLQG 393-088
RLQG 394-088
Uin
(ppm)
6.44
3.87
0.58
0.99
U
(ppm)
1.22
1.03
1.89
2.01
Th
(ppm)
5.84
2.33
0.15
0.65
K
(%)
1.23
0.73
0.24
0.31
ESR-age
(ka)
28.2 ± 2.4
58.2 ± 6.9
76.0 ± 10.5
13.5 ± 1.8
150
ESR intensity
Lab No.
100
50
References
Forman SL. 1999: Infrared and red stimulated luminescence dating of Late Quaternary near-shore sediments from
Spitsbergen, Svalbard. Arctic, Antarctic, and Alpine Research 31, 34-49.
Forman SL & Miller GH. 1984: Time dependent soil morphologies and pedogenic processes on raised beaches,
Bröggerhalvöya, Spitsbergen, Svalbard archipelago. Arctic and Alpine Research 16, 381-394.
Miller GH, Sejrup HP, Lehman SJ & Forman SL. 1989: Glacial history and marine environmental change during the last
interglacial-glacial cycle, western Spitsbergen, Svalbard. Boreas 18, 273-296.
Molodkov, A. 1988: ESR dating of Quaternary shells: recent advances. Quaternary Science Reviews 7, 477-484.
Molodkov, A. 1993: ESR-dating of non-marine mollusc shells. Applied Radiation and Isotopes 43, 145-148
0
-40 -20
0
20 40 60 80 100 120
Dose,Gy x 10
Dose dependence curve for
ESR-sample RLQG 376088.
? OSL+ESR/C14
? OSL
76±11 ka ESR
13.5±1.8 ka ESR
? OSL+ESR/C14
35±3 ka OSL
37±3 ka OSL
5
0
Extended growth curve (left) and stimulation curve (right) for
an aliquot of sample 081326. The signal is based on the
integral of the first 0.8 s of the decay less a background based
on the 0.96-1.6 s interval.
?
Glaciation
4
2
20
Glaciation
6
Dose recovery
8000
Frequency
8
? OSL
109±7 ka OSL
113±7 ka OSL
? OSL
(modern analog)
?
108±12
111±9
OSL (cts per 0.16 s)
16
15
Lx/Tx
25
80±10 ka
~5 m
B
70±10 ka
99±6
99±7
93±6
? OSL
The data points used for ESR
dose-response curves are the
means of up to ten measurements
of g = 2.0012 ESR signal
(Molodkov 1988, 1993) for each
aliquot. Quantification of the
2.0012 centre concentration was
obtained from the peak-to-peak
amplitude in derivative spectra by
using an overmodulation (OM)
detection method.
More
Schematic profile across Kvadehuksletta, vertically exaggerated and not to scale,
showing OSL- and ESR-dates. Samples with ’?’ are pending.
Understanding ice-sheet/ocean
interplay
Understanding the ice-sheet/ocean interplay depends upon a
well established chronology of the glacial events. The first
important step towards correlation of the land and marine
records will be resolving the ESR vs OSL discrepancy. Our
preliminary results raise concerns with respect to the validity of
chronologies based on only one of the methods.
OSL-data (preliminary data in grey)
Sample
no
081323
081333
081324
081325
081326
081327
081334
081328
081329
081330
081335
081331
081336
081332
081337
081338
081339
081340
081341
081342
081343
081352
081353
081354
081355
Site
Site 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
SIte 15
Tønsneset
Tønsneset
Kvadehuksletta
Kvadehuksletta
Kvadehuksletta
Kvadehuksletta
Depth
(cm)
150
280
700
730
800
950
900
1400
1450
1450
1450
2050
2250
2500
2600
2650
2680
2700
0
95
140
180
180
460
460
Age
Dose
(ka)
36 ± 3
90 ± 5
99 ± 6
99 ± 7
93 ± 6
108 ± 12
111 ± 9
138 ± 13
123 ± 8
117 ± 8
164 ± 14
174 ± 11
188 ± 12
243 ± 18
172 ± 13
185 ± 15
159 ± 13
198 ± 46
1.8
0.7
113
109
35
37
±
±
±
±
±
±
0.3
0.2
7
7
3
3
(Gy)
29 ±
113 ±
87 ±
109 ±
128 ±
104 ±
125 ±
104 ±
116 ±
115 ±
153 ±
133 ±
143 ±
158 ±
138 ±
109 ±
125 ±
128 ±
0.3 ±
3.5 ±
1.2 ±
118 ±
111 ±
43 ±
40 ±
2
3
2
5
5
11
8
7
4
4
11
3
5
5
5
5
6
4
0.08
0.5
0.3
4
4
3
2
n
26
25
25
26
28
29
8
34
23
22
15
23
19
15
15
24
13
27
8
16
14
26
25
26
24
Dose rate
(Gy/ka)
0.79 ± 0.04
1.26 ± 0.05
0.88 ± 0.05
1.10 ± 0.05
1.38 ± 0.06
0.96 ± 0.05
1.13 ± 0.05
0.75 ± 0.05
0.94 ± 0.05
0.99 ± 0.05
0.93 ± 0.04
0.76 ± 0.04
0.76 ± 0.04
0.65 ± 0.04
0.80 ± 0.05
0.59 ± 0.04
0.79 ± 0.05
0.65 ± 0.15
1.95
1.74
1.05
1.02
1.23
1.10
±
±
±
±
±
±
0.08
0.07
0.06
0.05
0.05
0.06
w.c(%)
32
35
27
34
34
34
29
34
23
30
31
29
31
31
30
29
30
34
23
20
24
27
25
25