TEMPORAL VARIABILITY OF CAVE-AIR CO2 IN CENTRAL TEXAS
- Permanent Link:
- TEMPORAL VARIABILITY OF CAVE-AIR CO2 IN CENTRAL TEXAS
- Series Title:
- Journal of Cave and Karst Studies
- Cowan, Brian D.
Osborne, Michael D.
Banner, Jay L.
- Publication Date:
- Subjects / Keywords:
- Cave-Air ( local )
Carbon Dioxide ( local )
Speleothems ( local )
Environmental Change ( local )
Caves ( local )
- serial ( sobekcm )
- The growth rate and composition of cave calcite deposits (speleothems) are often used as proxies for past environmental change. There is, however, the potential for bias in the speleothem record due to seasonal fluctuations in calcite growth and dripwater chemistry. It has been proposed that the growth rate of speleothem calcite in Texas caves varies seasonally in response to density-driven fluctuations in cave-air CO2, with lower growth rates in the warmer months when cave-air CO2 is highest. We monitored CO2 in three undeveloped caves and three tourist caves spread over 130 km in central Texas to determine whether seasonal CO2 fluctuations are confined to tourist caves, which have been modified from their natural states, and the extent to which cave-air CO2 is controlled by variations in cave geometry, host rocks, cave volume, and soils. Nearly150 lateral transects into six caves over three years show that CO2 concentrations vary seasonally in five of the caves monitored, with peak concentrations in the warmer months and lower concentrations in the cooler months. The caves occur in six stratigraphic units of lower Cretaceous marine platform carbonate rocks and vary in volume (from 100 to .100,000 m3) and geometry. Seasonal CO2 fluctuations are regional in extent and unlikely due to human activity. Seasonal fluctuations are independent of cave geometry, volume, depth, soil thickness, and the hosting stratigraphic unit. Our findings indicate that seasonal variations in calcite deposition may introduce bias in the speleothem record, and should be considered when reconstructing paleoclimate using speleothem proxies.
- Original Version:
- Journal of Cave and Karst Studies, Vol. 75, no. 1 (2013-04-01).
- Source Institution:
- University of South Florida Library
- Holding Location:
- University of South Florida
- Rights Management:
- This object is protected by copyright, and is made available here for research and educational purposes. Permission to reuse, publish, or reproduce the object beyond the bounds of Fair Use or other exemptions to copyright law must be obtained from the copyright holder.
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