- Title
- Carbon dioxide concentration in temperate climate caves and parent soils over an altitudinal gradient and its influence on speleothem growth and fabrics
- Creator
- Borsato, Andrea; Frisia, Silvia; Miorandi, Renza
- Relation
- Earth Surface Processes and Landforms Vol. 40, Issue 9, p. 1158-1170
- Publisher Link
- http://dx.doi.org/10.1002/esp.3706
- Publisher
- John Wiley & Sons
- Resource Type
- journal article
- Date
- 2015
- Description
- Carbon dioxide (CO₂) concentrations in caves and parent soils in the Italian Alps have been studied along a 2100 m altitudinal range – corresponding to a mean annual temperature (MAT) range of 12°C – in order to investigate the relationship between MAT, soil pCO₂ and cave air pCO₂, and to test the influence of soil pCO₂ on speleothem growth and fabric to ultimately gain insight into their palaeoclimatic significance in temperate climate settings. Our findings indicate that soil CO₂ is linearly correlated to MAT and its mean annual concentration is described by the equation: soil CO₂ (ppmv) = 1112 + 460 MAT. Soil pCO₂ can also be exponentially correlated to actual evapotranspiration. The pCO₂ in the aquifer is linearly correlated to MAT at the infiltration site and is more influenced by summer soil pCO₂. Cave air CO₂ in the innermost part of the caves exhibits a similar seasonal pattern, and commonly reaches concentrations of about 15% to 35%, with respect to the corresponding soil values, and is exponentially correlated to the MAT at the infiltration site. The combination of these parameters (soil pCO₂, dripwater pCO₂ and cave air pCO₂) results in speleothem growth and controls their fabrics which are typical of four MAT/elevation belts broadly corresponding to the present-day vegetation zones. In the lower montane zone [100–800 m above sea level (a.s.l.)] speleothems mostly consist of columnar fabric, in the upper montane zone (800–1600 m a.s.l.) both columnar and dendritic fabrics are common, the Subalpine zone (1600–2200 m a.s.l.) is characterized mostly by moonmilk deposits, whereas in the Alpine zone (above 2200 m a.s.l.) no speleothems are forming today. Therefore, fabric changes in fossil speleothem can potentially be used to reconstruct MAT changes in temperate climate karst areas.
- Subject
- carbon dioxide; karst soils; speleothem fabrics; caves; temperature gradient
- Identifier
- http://hdl.handle.net/1959.13/1331157
- Identifier
- uon:26553
- Identifier
- ISSN:0197-9337
- Language
- eng
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