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| Titel |
High-Resolution Isotopic Monitoring of Cave Air CO2 |
| VerfasserIn |
Paul Töchterle, Yuri Dublyansky, Magda Mandic, Nils Stöbener, H. J. Jost, Christoph Spötl |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250129174
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| Publikation (Nr.) |
 EGU/EGU2016-9248.pdf |
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| Schlagwörter |
Höhle, Monitoring, Isotope, Höhlenluft, CO2-Gehalt, Messung |
| Geograf. Schlagwort |
Österreich, Tirol, Schwaz (Bezirk), Spannagelhöhle, Zillertaler Alpen |
| Blattnummer |
149 [Lanersbach] |
| Blattnummer (UTM) |
2230 [Mayrhofen] |
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| Zusammenfassung |
| This study aims at characterising the ventilation patterns in Spannagel Cave, a high-alpine
cave system in the Zillertal Alps, Austria. A Thermo Scientific Delta Ray Isotope
Ratio Infrared Spectrometer was installed in a chamber ca. 100 m behind the cave
entrance to monitor pCO2 and δ13C and δ18O of CO2 at high temporal resolution (up
to 1 s). The air temperature was independently monitored inside and outside the
cave.
This study aims at characterising the ventilation patterns in Spannagel Cave, a high-alpine
cave system in the Zillertal Alps, Austria. A Thermo Scientific Delta Ray Isotope
Ratio Infrared Spectrometer was installed in a chamber ca. 100 m behind the cave
entrance to monitor pCO2 and δ13C and δ18O of CO2 at high temporal resolution (up
to 1s). The air temperature was independently monitored inside and outside the
cave.
The data show two distinct patterns in terms of CO2 concentration and its isotopic
composition, which are closely coupled with the temperature difference between the cave
interior and the outside atmosphere. This gradient controls the direction of air flow in the cave
on a seasonal to synoptic timescale (chimney-type ventilation).
The summer circulation is characterised by CO2 closely resembling atmospheric values
(pCO2 = 399 ± 12 ppm, δ13C = −8.5 ± 0.7 permil, δ18O = 8.1 ± 2.5 permil). The
winter circulation mode features generally higher CO2 concentrations and lower isotopic
compositions (pCO2 = 409 ± 14 ppm, δ13C = −10.1 ± 0.7 permil, δ18O = 2.3 ± 1.5
permil).
The high temporal resolution of stable isotope data allows tracking cave air ventilation
changes, including transient and short-lived ones. Moreover, the data make it possible to
address concomitant geochemical processes, such as the input of atmospheric CO2 and the
degassing of CO2 from seepage water. These processes would not be possible to quantify
without the new generation of laser-based isotope ratio instruments represented by the Delta
Ray. |
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