Magnetic Susceptibility of the Ponnaiyar River Sediments, Tamilnadu, India

Magnetic susceptibility measurements are performed on 40 sediment samples collected from the Ponnaiyar river, Tamilnadu. Measurement of magnetic susceptibility of sediments, reflecting magnetic enhancement of top sediments due to the atmospherically deposited magnetic particles of anthropogenic origin as well as approximate determination of environmental contamination. One of the natural limitations of this method is magnetic enhancement of sediments caused by weathering magnetically rich parent material. Magnetic susceptibility ranges from 11.00x 10 m /kg to 260.10x 10 m /kg. Within the upper most 100km from 8 3 8 3 the origin show lower susceptibility values than next 100km of the river. More downstream of the river has quite higher magnetic susceptibility (>150x 10 m /kg) values. However, some elevated values are also observed in 8 3 first 100km. Frequency dependence of magnetic susceptibility is calculated to understand the magnetic grain variations which are presented and discussed. It varies from 0.12 to 8.56%. SP/SD grains are contributed to the total susceptibility at S , S , S S , S and S The multi domain grains may contribute to the total magnetic 12 19 21, 35 37 38. susceptibility in other sites. The ranges of magnetic susceptibility values are compared with literature values. The observed behavior from the magnetic susceptibility and percentage of frequency dependence susceptibility indicates high concentration of ferrimagnetic minerals may exist at different sites.