The magnetic susceptibility analyzes of Motonuno lake sediment in Muna Regency, Southeast Sulawesi, Indonesia

Abstract

Study on the magnetic susceptibility, magnetic mineral, and content of element contained in the sediment has been done at Motonuno Lake Sediment in Muna Regency, Southeast Sulawesi Indonesia. Sediment samples in the form of cores were taken from three different sites by using the gravity core tool. Measurement of the magnetic susceptibility values was carried out by using the MS2C susceptibilitymeter. Content of element in the sediment was measured by using the SEM-EDX tool. The results showed that the magnetic susceptibility of sediment is -1 x 10-5 SI to 3 x 10-5 SI (site 1) and -2 x 10-5 to 2 x 10-5 SI (site 2 and site 3). Based on the value of magnetic susceptibility, the dominant magnetic mineral in the three sediment cores is pyrite (FeS2) which is an authgenic magnetic mineral. All three sediment core samples show that magnetic susceptibility values tend to be higher at the bottom of core than the top of core. This means that the sediment deposition takes place on different climate conditions, namely dry climate and wet climate. The elements contained in the sediment consists of O, Ca, Si, S, Al, Na, Cl, Fe, Mg, Au, Ti, Co, Cu, and Ni. All magnetic informations obtained in this study are very important in the understanding of paleoclimate condition at Motonuno Lake and its surrounding areas.