Geological Interpretation of Potential Field Data of Diara, District Sikar, Rajasthan

摘要

The aim of potential field data, viz. gravity and magnetic, interpretation is to elicit geological information. Present study on potential field data has been carried out for an area near Diara, located about 35 km east of Sikar, Rajasthan. The area forms a part of Albititite Line of Rajasthan and is comprising of quartzite, quartz biotite schist and calc-silicate rocks of Ajabgarh Group of Khetri sub basin of North Delhi Fold Belt. The NE-SW trending metasedimentary sequence of the area has been subjected to igneous intrusion and polyphase deformation. The study area is flanked by steeply dipping quartzite hill in the west, is mostly soil covered that delimited detailed geological mapping. Hence, ground gravity and magnetic survey was carried out. Quantitative analysis of magnetic and gravity anomalies indicated depth of causative sources of anomalies. The surveys resulted in delineating a linear basic body concordant to the formational strike occurring at a depth of 50-100 m manifested as prominent magnetic high. Subtle variation in Bouguer anomaly reflects lithological variation. Various data enhancement techniques are used to amplify and resolve the anomalies for better interpretability. Major structures interpreted from the potential field datasets are having NE-SW and E-W trends. NE-SW trending lineaments traverse all through the area and can be correlated with earlier phase of deformation of North Delhi Fold Belt. Effects of later episode of E-W faulting correlating with last phase of deformation can be seen in fragmentation of the basic body. Mutual relationships of interpreted litho-structural attributes indicate faults are post granitic intrusions. Interpretation of potential field data aiding the refinement of geological knowledge of the area is well correlated with drillhole data. An interpreted geological map of the area has been prepared from the potential field datasets.