A preliminary ground magnetic and resistivity investigations on Deidei geothermal area, Papua New Guinea

Abstract

Summary The linear discontinuity in the magnetic data pattern which separates the contrasting magnetic intensity areas to the north and south coincides with the location and orientation of the major east-west trending and southerly dipping near vertical fault structure observed at Galagalalana and Seuseulina thermal sites in the west and also with the Bolousunamo fumarole site on higher land area toward the east. Moderate to low magnetic intensity anomalies were concentrated toward the south side of the linear discontinuity thus indicating intense hydrothermal activity (or alteration) toward the south. This also suggests that the localized up flow on the structure (faults) may have been pushed toward the south due to the N-S hydrological gradient thus causing demagnetization to the south. A preliminary model proposed for Deidei geothermal system suggests neutral chloride outflow at low land areas (Seuseulina and Yaiyaiboalana boiling springs) towards the west and steam and hot pressurized water up flow at higher land areas (Bolousunamo acid sulphate fumarole) toward the east.