GEOCHEMISTRY AND ROCK MAGNETIC ANALYSIS ON SURFACE SEDIMENT IN LAMPENISU RIVER: A QUEST FOR MG SOURCE TO LAKE TOWUTI, INDONESIA

Sediment from Lake Towuti has been extensively studied to reconstruct past climate and environmental changes. One of the remaining questions is source magnesium (Mg) calcium (Ca) in northern part Towuti. In this study, high Mg Ca content examined by analysing surface sediment Lampenisu River (LR) Mahalona (MR) that merge before entering Twelve sediments MR, LR, confluence two rivers (LMR) were subjected geochemical (XRF), mineralogical (XRD), rock magnetic (susceptibility hysteresis parameter) analyses. The result shows LR samples are higher than MR samples. have a susceptibility lower frequency dependent XRD analyses on extracted grains show presence minerals with sodalite crystal structure, possibly valleyite but not If indeed occurs samples, it may contribute their relatively content. At same time, likely due serpentinized peridotite rocks. thereby considered be portion This study importance sediment-source identification big lakes such as Towuti, where influx could come several around lake.