| SPELEOTHEMS |
Shopov et al. 1996 Cold Water Cave, Iowa Speleothem Luminescence Data
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Shopov, Y.Y. 1996 Speleothems as Natural Climatic Stations with Annual to Daily Resolution. in "Climatic Change- the Karst
Record" Ed. by S.E. Lauritzen, KWI, Bergen, p. 150-151. ISSB 0-9640258-1-7.
| Data Coverage |
North: 43.18 * South: 43.18 |
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West: -91.86 * East: -91.86 |
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Altitude: 370 m |
Start Year: 1652 AD
End Year: 1982 AD
Data: Please Cite Data Contributors!
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Summary: Calcite speleothems luminescence (Shopov 1987, Shopov et al. 1994)
depends exponentially upon soil temperatures that are determined
primarily by solar infrared radiation in the case when that cave
is covered only by grass or upon air temperatures in case that
cave is covered by forest or bush. In the first case, microzonality
of luminescence of speleothems can be used as an indirect Solar
Insolation (SI) index, but in the second - as an paleotemperature proxy.
So, in dependence on the cave site we may speak about "solar sensitive"
and "temperature sensitive" luminescent speleothem records like in
treering records, but in our case record may depend either only on
temperature or on solar irradiation: - In case of Cold Water Cave (CWC),
Iowa, US we obtained high correlation coefficient of 0.9 between the
luminescence record and Solar Luminosity Sunspot index (Fig.1) and
reconstructed sunspot numbers since 1000 AD with precision within the
experimental error of their measurements; - in case of Rats Nest cave
(RNC), Alberta, Canada we measured correlation coefficient of 0.67
between luminescence intensity and air temperatures record for the
last 100 years (Fig.2) and reconstructed annual air temperatures
for last 1500 years at the cave site with estimated error of 0.35 C,
while the error of the direct measurements is 0.1 C. Intensity of
luminescence was not dependent on actual precipitations and sunspot
numbers (zero correlation). Speleothem growth rate variations
represent mainly rainfall variations. Speleothem luminescence
visualizes annual microbanding we used to derive proxy records of
annual precipitations or the cave site. In case of RNC we reconstructed
annual precipitations for last 280 years at the cave site with estimated
error of 80 mm/year. By comparison of luminescent records with other
solar proxy records we obtained a reconstruction of growth rates
and precipitations in Bosnek karst region near Duhlata cave (DC),
Bulgaria for the last 50000 years, and for the last 6400 years
(with averaged time step of 41 years) for Iowa, near CWC. Achieved
time step of 6 hours (Fig.3) in speleothem luminescence records
allows resolution of several days in some best speleothem samples.
Annual luminescence microbanding was used very successfully for
relative and absolute dating of speleothems by Autocalibradion dating
(Shopov et al. 1991). This dating method appear to be more precise
than TAMS 14C and AMS U/Th dating for relative dating of short time
intervals and only dating method for speleothems with little uranium,
younger than 2000 years. It is demonstrated, that speleothems can
be used as natural climatic stations with annual resolution for
purposes of climatology and agrometeorology for a time span far
exceeding all historic records.
More Info on Speleothems |
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Complete XML Record: noaa-cave-6097
(Last Revised: 2009-02-11 )
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