| Abstract |
A geochemical soil survey was conducted over a sediment hosted low enthalpy resource at Naike, New Zealand. Samples were taken on a 250m x 250m grid, covering about 2.5 km2, from both the A and B horizons. Soil ammonia (or, more strictly, ammonium) was selected as the pathfinder species since this attains high levels in geothermal fluids from sedimentary hosted reservoirs. The A horizon showed a stronger anomaly contrast than the B horizon. IN the A horizon, the mean background concentration, as determined by probability plots, was 2 mg ND3/kg, with anomalous values up to 25 mg ND3/kg and a threshold of 4 mg ND3/kg. The results define a pattern of anomalies which parallel known faults, thereby implying a fracture dominated hydrology - a conclusion supported by previous geophysical surveys. |