Perpustakaan Digital ITB

Bandung Basin in West Java Indonesia is surrounded by active volcanoe,s many springs and hot springs associated with geothermal activities were found in the Basin. Related with the condition there is potential release of dissolved metals into groundwater and surface water as well as the potential for mineral deposition of metals in soil. Purpose of this study is to determine the type and genesis of water as well as the mechanism of metal dissolution in groundwater. Geochemistry of water and solids were used to find out the mechanism of release and sink of metals in springs and sediments. To analyze the mechanism, 11 samples were used, 9 samples from Bandung Basin and two samples from outside Bandung Basin. To answer the problem, hydro geochemical methods were used, including trace element analysis and stable isotope analysis. For solid samples, mineralogical compositions of sediment and host rocks were determined by XRD, SEM, and elemental mapping. Based on this study four types and different mechanism can be distinguished, those are; 1) mixing type of shallow groundwater with hydrothermal fluids, 2) young groundwater from meteoric water, 3) heated groundwater by conductive hot rocks and 4) dominant of magmatic fluids. Mineralogical analyses showed that jarosite, illite and quartz were found at type 1 and 4 as well as metal content such as Fe, As and Hg in water and sediment in those types were found higher.