| Title | CO2-Flux of Steaming Ground at Karapiti, Wairakei |
|---|---|
| Authors | Cindy A. Werner, Manfred P. Hochstein, & Chris J. Bromley |
| Year | 2004 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | |
| Abstract | The diffuse discharge of CO2 over the 0.35 km2 Karapiti steaming ground area was obtained from accumulation chamber measurements at sites where the soil steam flux had been measured or could be inferred from a separate heat flux survey. The distribution of CO2 fluxes is skewed and measurements exhibit significant temporal and spatial variability. Allowing for a biogenic background flux, the geothermal emission for the whole area was found by integration of contours to be c. 6 t CO2/d. Using the measured CO2 and steam flux data, an apparent soil-gas ratio was computed which points to a similar emission rate (c. 7 t CO2/d). The CO2 discharged by all fumaroles was found to be 16 ± 2.3 t/d, suggesting that the total CO2 discharge at Karapiti is c. 23 ± 7 t /d, and that most of the CO2 is emitted through focussed venting. The CO2 emission at Karapiti is moderate in comparison to that of other hydrothermal sites. It amounts only to c. 12 % of the total amount of CO2 produced in recent years by exploitation of the nearby Wairakei geothermal reservoir. |