| Abstract |
Parker Volcano lies along the Sangihe volcanic arc, a Quaternary volcanic chain running from Sulawesi, Indonesia to Central Mindanao. The volcanic complex developed over the folded Miocene sediments of the South Cotabato Basin which are composed chiefly of limestone, and fine to coarse grained clastics. Volcanic deposits include dacite and andesite and very extensive pyroclastics. The major structural grain of the region runs northwest with a conjugate northeast trend. Neutral sulphate springs and seepages effuse at Lake Maughan, the crater lake of Mt. Parker. It is apparent that the cold meteoric waters of the lake has a quenching and effects on the ascending hot gases beneath the crater region. The lake also act as the sink of gaseous constituents of the system as indicated by the high-sulphate level in the lake waters. Neutral chloride waters percolate along the structures around the volcano and spring out towards: Bungo in the southeast, Salvan and Bagong Silang in the east, and Islakit and Tinulang in the northeast. The close values of ratios among these springs, from 0.015 to 0.023, indicate homogeneity of the fluid source and the presence of "andesitic" thermal system. The dilution trends of warm and hot spring models support the single-source of the fluids and give an estimate reservoir fluid temperature of about 230 to 250 C. |