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Mishra, V. P.
- Kimberlites, Lamproites and Lamprophyres of India: A Petrographic Atlas
Authors
1 Geological Survey of India, 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: 467-504Abstract
A pictorial display of some of the kimberlites, lamproites and lamprophyres of India, is given in this work. This would give an idea about the texture and mineralogy of these rocks from different cratonic regions of the Indian shield.Keywords
Kimberlites, Lamproites, Lamprophyres, Petrography, Atlas.- 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.- Discovery of Animal Eggs and Embryos from the Ediacaran (Terminal Proterozoic) Chambaghat Formation, Krol Group, Himachal Lesser Himalaya
Authors
1 Palaeontology Division, Geological Survey of India, Sector-E, Aliganj, Lucknow - 226 024, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 74, No 4 (2009), Pagination: 498-502Abstract
The globular to suboval microfossils with distinctively ornamented outer coverings interpreted as animal eggs and embryos have been discovered from the black phosphatic chert lentils of the Ediacaran (Terminal Proterozoic) Chambaghat Formation (Krol sandstone), Krol Group, Himachal Lesser Himalaya, India. Similar animal eggs and embryos have earlier been recorded only from the phosphorites of the uppermost Neoproterozoic Doushantuo Formation (Ca. 570±20 Ma) exposed at Weng'an, South China. Present record of eggs and embryos is comparable with extant eggs and embryos of cnidarians and bilaterians like molluscs, annelids and arthropods. The eggs and embryos from the Terminal Proterozoic rocks of India are the only one recorded from the equivalent stratigraphic horizon outside China. This discovery of eggs and embryos adds to the understanding the evolutionary trends in the Proterozoic metazoan life.Keywords
Eggs, Embryos, Ediacaran, Proterozoic, Krol Group, Himachal Lesser Himalaya.References
- AUDEN, J.B. (1934) Geology of Krol Belt. Rec. Geol. Surv. India, v.67(4), pp.357-454.
- CHEN, JUN-YUAN, OLIVERI, P., LI, CHIA-WEI, ZHOU, GUI-QING, FENG, GAO, GADORN, J.W., PETRSON, K.J. and DAVIDSON, E.H. (2000) Precambrian animal diversity: Putative phosphatized embryos from the Doushanuo Formation of China. Nat. Acad. Sci. Proc., v.57, pp. 4457-4462.
- JENKINS, R.J.F., MCKIRDY, D.M., FOSTER, C.B., O'LEARY, T. and PELL, S.D. (1992) The record and Stratigraphic implications of organic walled microfossils from the Ediacaran (terminal Proterozoic) of South Australia. Geol. Mag., v.129, pp.401- 410.
- JIANG, G., SOHL, L.E. and CHRISTIE-BLICK, N. (2003) Geology, Neoproterozoic stratigraphic comparison of the Lesser Himalaya (India) and Yangtze block (Yangtze block, south China): Paleogeographic implications. Geology, v.31(10), pp.917-920.
- KNOLL, A.H. (1992) Microfossils in metasedimentary chertsof Scotia Group, Prins Karls Forland, Western Svalbard. Palaeontology, v.35, pp.751-774.
- KNOLL, A.H. and WALTER, M. (1992) Latest Proterozoic stratigraphy and Earth history. Nature, v.356, pp.673-678.
- KNOLL, A.H., NARBONNE, G.M., WALTER, M.R. and CHRIESTE-BLICK, N. (2006) The Ediacaran Period: a new addition to the geologic time scale. Lethaia, v.39, pp.13-30.
- KUMAR, GOPENDRA, SHANKER RAVI, MATHUR, V.K. and MAITHY, P.K. (2000) Maldeota Section, Mussoorie Syncline, Krol Belt, Lesser Himalaya, India: A candidate for Global Startotype Section and Point for Terminal Proterozoic System. Geoscience Jour., v.XXI(1), pp.1-10.
- LIN, JIH-PAI, SCOTT, A.C., LI, CHIA-WEI, WU, HUNG-JEN, AUSICH, W.I., ZHAO, YUAN-LONG and HWU, YEN-KUANG (2006) Silicified egg clusters from Middle Cambrian Burgess shale-type deposit, Guizhon, South China. Geology, v.34(12), pp.1237-1240.
- MATHUR, V.K. (1989) Biostratigraphic studies of the Krol Belt, Lesser Himalaya, India. Rec. Geol. Surv. India, v.122(8), pp.293-295.
- MATHUR, V.K. (2008) Ediacaran multicellular biota from Krol Group, Lesser Himalaya and its Stratigraphic significance – a review. The Palaeobotanist, v.57, pp.53-61.
- MATHUR, V.K. and SHANKER, RAVI (1989) First record of Ediacaran fossils from the Krol Formation, Nainital Syncline. Jour. Geol. Soc. India, v.34, pp.245-254.
- MATHUR, V.K. and SHANKER, RAVI (1990) Ediacaran medusoids from the Krol Formation, Nainital Syncline. Jour. Geol. Soc. India, v.36, pp.74-78.
- SHANKER, RAVI and MATHUR, V.K. (1992) Precambrian-Cambrian sequence in Krol belt and additional Ediacaran fossils. Geophytology. v.22, pp.27-39.
- SHANKER, RAVI, BHATTACHARYA, D.D., PANDE, A.C. and MATHUR, V.K. (2004) Ediacaran biota from the Jarashi (Middle Krol) and Mahi (Lower Krol) Formations, Krol Group, Lesser Himalaya, India. Jour. Geol. Soc. India, v.63(6), pp.649-654.
- SHANKER, RAVI, KUMAR, G., MATHUR, V.K. and JOSHI, A. (1993) Stratigraphy of Blaini, Infra Krol, Krol and Tal succession, Krol belt, Lesser Himalaya, India, Indian Jour. Petrol. Geol., v.2, v.99-136.
- SHUKLA, M., BABU, R., MATHUR, V.K. and SRIVASTAVA, D.K. (2005) Microbial remains from the Chambaghat Formation, Krol Group, Sirmaur district, Himachal Lesser Himalaya, India and their significance. Curr. Sci., v.88(8), pp.1223-1225.
- SHUKLA, M., MATHUR, V.K., BABU, R. and SRIVASTAVA, D.K. (2008) Ediacaran microbiota from Baliana and Krol groups, Lesser Himalaya, India. The Palaeobotanist, v.57, pp.359-378.
- TEWARI, M. and KNOLL, A.H. (1994) Large acanthomorphic acritarchs from the Infra Krol Formation of the Lesser Himalaya and their stratigraphic significance. Him. Geol., v.5(2) pp.193-201.
- VIDAL, G. (1990) Giant acanthomorph acritarchs from the Upper Proterozoic in southern Norway. Palaeontology, v.33 pp.287- 298.
- XIAO,S., HAGADORN, J.W., ZHOU, C. and YUAN, X. (2007) Rare helical spheroidal fossils from the Doushantuo Lagerstatte : Ediacaran animal embryos come of age? Geology, v.35(2), pp.115-118.
- XIAO, S. and KNOLL, A.H. (2000) Phosphatized animal embryos from the Neoproterozoic Doushantuo Formation at Weng'an Guizhon, South China. Jour. Palaeon., v.74(5), pp.767-788.