Geochemical Correlation of Volcanic Rocks and Groundwater Quality in the Todoko-Ranu Complex, Sahu District, West Halmahera, North Maluku, Indonesia

The research area is located in the Mount Todoko-ranu complex and its surroundings, Sahu District, West Halmahera Regency, North Maluku, Indonesia. This area geologically consists of Quaternary volcanic rocks with various petrochemical composition. On the other hand, natural water found in the research area generally physically appears turbid, while people who take water from this sites actually need clean water. As it is known, groundwater quality is influenced by the geochemistry of the aquifer through which it flows, therefore it is important to conduct a study on the geochemical correlation of volcanic rocks and groundwater quality in the research area. Thus, the aim of this research is to examine the geochemical characteristics of Mount Todoko-Ranu complex volcanic rocks, to analyze groundwater quality, and to study the correlation between the geochemical characteristics of rocks and the quality of groundwater in this volcanic complex. Methodology applied in this study was geological mapping, rock samples testing to determine the mineralogy chemical composition, groundwater, and surface water samples testing to identify their quality, and then correlation analysis. The results show that andesitic and basaltic-andesite of calc-alcaline volcanic rock complex is correlative to no dominant cation, but bicarbonate anion, or mixing type of natural water.