A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Gouda, H. C.
- Interpretation of Aeromagnetic Data of Panna and Adjoining Area, Parts of M.P. & U.P., for Evaluation of Structural Patterns Favourable for Emplacement of Kimberlite Clan of Rocks and Estimation of Depths of Magnetic Bodies
Authors
1 Geological Survey of India, GMC Division, AMSE Wing, Vasudha Bhavan, Kumaraswamy layout, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 69, No Spl Iss 3 (2007), Pagination: 653-663Abstract
The rocks of Vindhyan Supergroup overlying Bundelkhand Granites host the diamondiferous Kimberlite diatremes in Kaimur Group and diamondiferous conglomerates within the Rewa Group. This region, collectively referred as the 'Panna Diamond Belt' was flown by the Geological Survey of India aircraft during the years 2001-2002 and the aeromagnetic data generated are interpreted here. The survey was carried out at an altitude of 150 m above ground level with traverse spacing of 500 m.
The International Geomagnetic Reference Field (IGRF) corrected aeromagnetic data was brought to a plane at 600 m above msl and was subjected to terrain correction. Interpretation of this area yielded several structural trends in NE-SW, ENE-WSW, nearly E-W, nearly N-S and NW-SE directions in the form of magnetic discontinuities and linears, which are indicative of structural patterns like formational contacts/faults/fractures and body axes. The study area is characterized by a strong magnetic linear feature trending in ENE-WSW direction with intersections in nearly N-S direction representing transverse faults at some places and also intersected by two prominent features on either side, one around Majhagaon and the other towards north of Usrar. This prominent ENE-WSW trending magnetic feature is seen to fall along the contact of Vindhyan Supergroup with the adjacent Bundelkhand Granite Complex (BGC) and strong magnetic closures along this feature represent the intrusive activity at depth. In the northern part of the area occupied by BGC. Prominent magnetic features are obtained in the direction of NE-SW and few in N-S and E-W directions represent the fracture system.
The quantitative interpretation of aeromagnetic data employing radial power spectrum, matched filtering, 2-D, 3-D and contact modeling indicated the depths of causative sources. The radial power spectrum indicated three magnetic interfaces at 380 m, 1.3 km and 5.3 km from the plane of observation. The results of 2-D modeling of terrain corrected aeromagnetic data along Panna Diamond Belt yielded the depth range of 410 m-690 m from the observation plane correlatable with the interface at 380 m. The matched filtered map of second layer indicated the continuation of these magnetic bodies. The results of 3-D prism modeling of Reduced to Pole (RTP) data along Panna Diamond Belt indicated the depths in the range of 0.9 km-1.7 km from the observation plane, which is correlatable with the interface at 1.3 km. The matched filtered map of deep layer indicated that all the magnetic closures along Panna Diamond belt disappeared except a huge magnetic closure around Majhagaon-Hinota area. This appears to be a deep intrusive body and manifested in the form of different magnetic bodies at shallower depths. The depths of major NE-SW trending magnetic features in the northern part over BGC are of deeper nature. A few potential blocks were identified for search of possible emplacement of Kimberlite Clan of Rocks (KCRs).
Keywords
Aeromagnetic, Kimberlite, Panna.- Study of Structural Pattern through Aeromagnetic Data for Mineral Prospecting and Kimberlite Clan Rocks in an Area around Mahbubnagar, A.P.
Authors
1 Geological Survey of India, GMC Division, AMSE Wing, Vasudha Bhavan, Kumaraswamy Layout, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 72, No 2 (2008), Pagination: 175-189Abstract
The qualitative interpretation of aeromagnetic map of an area around Mahbubnagar, indicated several linears and discontinuities, which suggest the presence of various magnetic bodies and fractures, faults, and shears. The magnetic discontinuities trend in NW-SE, WNW-ESE, NE-SW, N-S and E-W directions. The quantitative interpretation indicated three magnetic interfaces at the depths of 4.5 km, 1.3 km and 670 m from the plane of observation at 675 m above m.s.l. The magnetic maps of different layers prepared by matched filtering have helped in understanding the structural setup. The study of these maps has indicated that major discontinuities (fractures/faults) extend to greater depths. The 2-D modelling revealed the dips of the bodies varying between 3°-27° indicating the near horizontal type of sources excepting the one with 69° dip. The depths to the top of these bodies were found to vary between 308 m-1180 m from the plane of observation. The 3-D prism modelling of selected anomalies indicated that most of them are near horizontal type of sources except a few. The depths to the top of these prism bodies vary between 440 m- 831 m and to the bottom between 682 m-7136 m from the plane of observation. This shows that majority of the magnetic bodies are emplaced in the surficial and shallow layers and few extend to greater depths. Based on this study, 15 blocks were identified as potential areas for mineral prospecting and also for possible emplacement of Kimberlite clan rocks (KCR).Keywords
Aeromagnetic, Mineral Prospecting, Mahbubnagar, Andhra Pradesh.- Structural Study through Aeromagnetic Data for Mineral Prospecting in Betul-Chhindwara Area, M. P.
Authors
1 Geological Survey of India, GMC Division, AMSE Wing, Vasudha Bhavan, Kumaraswamy Layout, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 71, No 6 (2008), Pagination: 815-826Abstract
The aeromagnetic map of Betul-Chhindwara area, contains two magnetic domains namely 'A' representing high amplitude anomalies falling over Deccan Traps and domain 'B' represented by moderate amplitude anomalies falling over gneiss and Gondwana Supergroup. The qualitative interpretation of aeromagnetic data has brought out several linears and discontinuities, which show the presence of various magnetic bodies and fractures/faults/shears/contacts respectively. The magnetic linears were found to trend mainly in ENE-WSW direction and few in E-W, NE-SW and NW-SE directions. The prominent magnetic discontinuities trending in ENE-WSW directions were found to be intersected by NW-SE, NE-SW and nearly N-S trending discontinuities at places. One of these prominent discontinuities was found to fall along granitic gneiss and others at the contact of gniesses with Gondwana Supergroup in northern part and with Deccan Traps in southern part. One prominent discontinuity was found within Gondwana Supergroup in the northern part and another in the southeastern part over the known Gavilgarh fault. The magnetic discontinuity obtained in the gneissic complex was found to fall over the known sulphide mineralisation near Banaskhapa-Piparia etc. and thus assumes importance for prospecting sulphide minerals all along the discontinuity.The quantitative interpretation was carried out by computing the radial power spectrum and by 2-D modelling of selected anomalies. The Radial power spectrum yielded two interfaces at the depths of 0 871 km and 9 461 km from observation plane (1080 m above msl). The shallow layer map is similar to that of the terrain corrected map whereas the deep layer map indicated the gradients corroborating with the discontinuities mentioned above excepting the one falling over granitic gneiss which was reflected as a broad elongated magnetic low. The results of 2-D modelling over ten selected anomalies suggest that most of the bodies are very shallow excepting two The dips of most of the bodies were found m between 6°-25° and few between 32°- 48°.
Keywords
Aeromagnetic, Mineral Prospecting, Betul, Madhya Pradesh.- Analysis of Aeromagnetic Data Over Part of Bundelkhand Granite Complex for Geology and Structure
Authors
1 AMSE Wing, Geological Survey of India, Vasudha Bhavan, Kumaraswamy Layout, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No 6 (2006), Pagination: 949-958Abstract
The interpretation of aeromagnetic data over Bundelkhand Granite Complex (BGC) in parts of Lalitpur District (U P), Sagar and Chhatarpur Districts (M P) has revealed the structural patterns such as the boundaries of various geological formations, magnetic body axes, depth extents of intrusives and thickness of various litho-Units which may be of help in mineral exploration. The aeromagnetic features were found to correspond well with various geological formations like Bijawars, Vindhyans, Deccan Traps and BGC. The average depths of magnetic interfaces were estimated to be at 71 km, 19 km and 0 47 km from the observation plane (625 m above m s 1). The thickness of Deccan Traps was estimated to be of the order of 0 47 km from the plane of observation. The ferrugenous bodies in Bijawars and intrusive bodies in BGC were found to disappear at the magnetic interface at 19 km from the observation plane. The Bijawars were found to be thickened gradually towards west of Didonia up to the deeper interface at 71 km from observation plane probably due to the presence of schistose rocks and basic/Ultrabasic intrusives at depth. The study of matched filtered maps indicated that Vindhyans continue beyond the interface of 19 km at places. The 3-D prism modeling results indicated that the depth extents of most of the bodies are found to be in-Between the two interfaces at 0 47 km and 1 9 km and some bodies continued even deeper. The area towards north and northeast of Sonrai has been recommended as having potential for base-Metal mineral prospecting.Keywords
Aeromagnetics, Bundelkhand Granite Complex, Geology, Structure, Lalitpur (U P), Chhatarpur (M P).- Structural Study of Meghalaya Plateau Through Aeromagnetic Data
Authors
1 RSAS, Geological Survey of India, Vasudha Bhavan, K.S. Layout, Bangalore – 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 79, No 1 (2012), Pagination: 11-29Abstract
The study of aeromagnetic data over parts of Assam-Meghalaya has delineated major discontinuities representing faults/fractures/contacts/shears and magnetic body axes, which helped in understanding the regional and structural setup of the area. The known Barapani and Dapsi Thrusts, Dudhnai Fault and three strong magnetic anomalies with reverse magnetisation have been delineated. The quantitative analysis of aeromagnetic data brought out the depths of magnetic interfaces and the magnetic picture of different layers, which also helped in understanding the regional and structural setup. The contact modeling across few profile sections showed the depths to the top of contacts and the map of magnetic-basement-depth-model revealed the undulations of the basement. Magnetic body axes of several magnetic anomalies and also several magnetic discontinuities representative of faults/ fractures/ contacts/ shears system in the area along with five potential blocks for mineral prospecting are the main outcome of this exercise. The seismotectonic activity associated with the magnetic features has also been studied to understand the structural setup.Keywords
Structural Study, Aeromagnetic Data, Meghalaya.References
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