Structural Mapping of Kutch Rift Basin from Aeromagnetic Data

Abstract

Kutch basin is an east-west oriented pericratonic rift basin at the western most periphery of the Indian craton which covers almost the entire Kutch district of the state of Gujrat. The region is conspicuously featured by uplands surrounded by lowlands. No outcrop is seen within the featureless plains and consequently subsurface information is lacking for these areas. The semi-detailed high resolution aeromagnetic data collected over the Kutch rift basin, which has a uniform coverage is analyzed in the present study. The qualitative interpretation using the crustal magnetic anomaly map suggests the major trend of the anomalies to be NW-SE and E-W, which agrees with the general trend of the basin while the minor one trends in NE-SW direction. Much of the high frequency anomalies are related to exposed and subsurface basaltic flows. One important finding is the presence of trap flows to the northwest of Kutch Mainland Fault which has not been previously reported. Different edge detection techniques were applied to the aeromagnetic data for the delineation of the major and minor magnetic contacts. From combined interpretation of the edge detection techniques like analytic signal, Horizontal Gradient Magnitude (HGM) and Euler deconvolution, we have mapped fourteen lineaments some of which does not have any surface expressions i.e., they lie within the sedimentary strata or in the Rann of Kutch. Many of these lineaments may represent basement related faults that have played a crucial role in the formation of the Kutch basin and may have been reactivated many times in the past and may have manifestation up to the surface.