Distribution Characteristics of Magnetic Susceptibility of Surficial  Sediments in the Western Taiwan Strait

Key words: 
• Taiwan Strait /
• magnetic susceptibility /
• frequency dependent susceptibility /
• sediments /
• sedimentation /
• ferrimagnetic minerals

Abstract: Magnetic susceptibility of 228 surface sediments, sampled from the offshore between Pingtan to Shantou, were measured with an attempt to understand the distribution characteristics and their dominative factors of magnetic susceptibility in the western Taiwan Strait.The results showed that the values of low frequency mass specific susceptibility(χlf) and frequency dependent susceptibility(χfd%) decreased gradually from shore to offshore, and the values of χlf were apparently higher in area north to the Xiamen Bay than those from the south. Our study also showed that χfd% at the east of Pingtan Island and the coastal areas of Shantou were relatively high Furthermore, it was obvious that the values decline from Pingtan Island to the south. In comparison with previous studies related to sedimentary types and heavy mineral distribution of the western Taiwan Strait, we discovered susceptibility the values were higher in the fine grained sediments nearshore while lower in the coarse grained sediments offshore in the western Taiwan Strait. The values of magnetic susceptibility correlated well with the content of magnetite, suggesting magnetic susceptibility and frequency dependent susceptibility were dominated by sedimentation process and the source of sediments. 