Quantitative Interpretation of Gravity and Magnetic Data over Southern Granulite Terrain Using Scaling Spectral Approach

In frequency domain, interpretation of gravity and magnetic measurements was carried out by the spectral method and its variants. The spectral method assumes the source distribution as white noise. Whereas the detailed analysts of borehole data from several areas reveal that physical properties such as density, susceptibility reflectivity sequences etc follow a scaling distribution. The scaling distribution of sources is incorporated in spectral method and the new approach is known as the scaling spectral method. This method is applied to the gravity and magnetic data of Kuppam-Palani geotransect in southern granulites of southern India. The depth values calculated for the Kuppam- Palani transect agree well with the seismic study. The deviation in the value of the scaling exponent for Mid-crustal layer shows the differing nature of the crust for Kuppam-Bhavani and Kolattur-Palani sections of the Kuppam-Palani transect. Further, different values of scaling exponent obtainable from gravity and magnetic data for the same depth indicate that sources for gravity and magnetic anomalies are different.