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| Titel |
Stable isotope records for the last 10 000 years from Okshola cave (Fauske, northern Norway) and regional comparisons |
| VerfasserIn |
H. Linge, S.-E. Lauritzen, C. Andersson, J. K. Hansen, R. Ø. Skoglund, H. S. Sundqvist |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1814-9324
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| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 5, no. 4 ; Nr. 5, no. 4 (2009-11-03), S.667-682 |
| Datensatznummer |
250002696
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| Publikation (Nr.) |
 copernicus.org/cp-5-667-2009.pdf |
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| Zusammenfassung |
The sensitivity of terrestrial environments to past changes in heat
transport is expected to be manifested in Holocene climate proxy records on
millennial to seasonal timescales. Stalagmite formation in the Okshola cave
near Fauske (northern Norway) began at about 10.4 ka, soon after the valley
was deglaciated. Past monitoring of the cave and surface has revealed stable
modern conditions with uniform drip rates, relative humidity and
temperature. Stable isotope records from two stalagmites provide time-series
spanning from c. 10 380 yr to AD 1997; a banded, multi-coloured stalagmite
(Oks82) was formed between 10 380 yr and 5050 yr, whereas a pristine, white
stalagmite (FM3) covers the period from ~7500 yr to the present. The
stable oxygen isotope (δ18Oc), stable carbon isotope
(δ13Cc), and growth rate records are interpreted as
showing i) a negative correlation between cave/surface temperature and
δ18Oc, ii) a positive correlation between wetness and
δ13Cc, and iii) a positive correlation between temperature
and growth rate. Following this, the data from Okshola show that the
Holocene was characterised by high-variability climate in the early part,
low-variability climate in the middle part, and high-variability climate and
shifts between two distinct modes in the late part.
A total of nine Scandinavian stalagmite δ18Oc records of
comparable dating precision are now available for parts or most of the
Holocene. None of them show a clear Holocene thermal optimum, suggesting
that they are influenced by annual mean temperature (cave temperature)
rather than seasonal temperature. For the last 1000 years, δ18Oc
values display a depletion-enrichment-depletion pattern
commonly interpreted as reflecting the conventional view on climate
development for the last millennium. Although the δ18Oc
records show similar patterns and amplitudes of change, the main challenges
for utilising high-latitude stalagmites as palaeoclimate archives are i) the
accuracy of the age models, ii) the ambiguity of the proxy signals, and iii)
calibration with monitoring data. |
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