Perpustakaan Digital ITB

Lake is a body of fresh or salt water, localized in a basin and surrounded by land apart from a river, stream, or other form of moving water that serves to feed or drain the lake. Towuti is one of the ancient lakes in the world, the largest lake in Sulawesi and affected by global climate systems, El Nino Southern oscillation (ENSO) and Indo-Australian Monsoon. Observation by scanning electron microscopy and energy dispersive X-ray (EDX) have been conducted on magnetic grains extracted from 6 samples from core TOW9, a 11.50 m long sediment core, of Lake Towuti, Indonesia. The purpose of this observation is to identify the morphology and composition of mineral magnetic therefore can indicate the reductive diagenesis, such as magnetite dissolution. Different kinds of iron oxides with various grain size, as well as paramagnetic iron carbonate (siderite) were identified but not the iron sulfide. Overall, the predominant magnetic mineral is magnetite, but hematite and maghemite were also found at the bottom of the core. The presence of iron oxides with various grain sizes and shapes at the bottom of the core show the presence of oxidation as well as physical diagenesis.