Analysis of aeromagnetic data for structural study over a part of Bundelkhand Granitoid Complex

摘要

The magnetic data show extension of the Bundelkhand Granitoid Complex (BGC) below the Indo-Gangetic alluvium in the northern part of the area. The change in the magnetic intensity from south to north in the magnetic domains 'A' and 'B' is attributed to the variations in magnetic susceptibility in the granites and other lithounits of BGC. The high-intensity magnetic domain 'A' comprises anomalies with high amplitude and shorter wavelengths whereas the moderate-intensity magnetic domain 'B' consists of anomalies of moderate amplitudes with moderate wavelengths. Magnetic data is characterised by the 2D type of features mainly trending NE-SW (magnetic discontinuities) and NW-SE (magnetic body axes) associated with quartz reefs and dolerite dykes respectively. The results of 2-D modelling have shown the variation in depth to the top of magnetic bodies in the range of 192 m to 350 m. There are nearly E-W- trending magnetic features which represent the general trend of the lithological unit in BGC. The radially averaged power spectrum has shown three magnetic interfaces at depths of 488 m, 1243 m and 8368 m below the observation plane. The magnetic features corresponding to these depths are presented in the layer maps generated by matched filtering. Many of the magnetic discontinuities are continuing from shallow to middle layer whereas magnetic body axes (except the L1-L1 and L2-L2) trending NW-SE have disappeared in the middle layer. The nearly E-W- trending magnetic body axes continue even in the deep layer which represent the general trend of the BGC. The magnetic basement depth model map shows shallow magnetic basement towards south and deeper magnetic basement towards north of the area. These magnetic discontinuities and nearly E-W-trending magnetic features are intersected by the NW-SE-trending magnetic body axes. Prominent regions of intersection of different magnetic features in the area are identified as potential blocks for detailed mineral investigation.