Distribución vertical del contenido en CO2 en la zona no saturada de un karst mediterráneo (Nerja, España): resultados preliminares

Abstract

Nine boreholes are located in a experimental site in the surroundings of Nerja Cave (Málaga). CO2 concentration, relative humidity and temperature logs have been made at the beginning of July, 2006. The same parameters were recorded during a period of several days at different depths. The research concerns the first 40 m of the unsaturated zone of a karstic aquifer developed in marbles of Triassic age. All CO2 concentrations increase in depth, with maximum values of 60.000 ppm, and are linked to temperatures and relative humidities between 20-23 ºC and 80-100 %, respectively. These conditions seem to be very stable at the studied depths, but at the sur face frequent changes are observed, always associated to upcoming and downcoming CO2 air fluxes. Boreholes that have crossed cavities show more variations in the gas content. Either the origin of CO 2 or air fluxes dynamics are being studied for a seasonal characterization