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Venkata Dasu, S. P.
- Sargur-Dharwar Relationship Around the Komatiite-Rich Jayachamarajapura Greenstone Belt in Karnataka
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Authors
Affiliations
1 Geological Survey of India, A.M.S.E. Wing, Church Street, Bangalore-560001, IN
2 Department of Geology, Bangalore University, Bangalore-560056, IN
1 Geological Survey of India, A.M.S.E. Wing, Church Street, Bangalore-560001, IN
2 Department of Geology, Bangalore University, Bangalore-560056, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 38, No 6 (1991), Pagination: 577-592Abstract
New geological and preliminary geochemical data presented here from J ayachamarajapura (JC Pura) reinforce the idea of orogenic separation of two sequences across a deformed angular un confonnity . The JC Pura belt forms a major structural dome linking a trail of enclaves to the north and south. Its main lithology is altered komatiites preserving excellent polyhedral joints, pillows, ocelli and spinifex texture. These peridotitic komatiites are closely associated with the basaltic komatiites now represented by dark shiny amphibolites.Cherty quartzites and BIF form minor units. This association is typical of the older greenstones (Sargur Group) of Kamataka. These lithologies are overlain unconformably by the basal quartz-pebble conglomerate and associated amygdular metabasalt - crossbedded quartz arenite alternations constituting the Bababudan Group in the Kibbanahalli arm of Chitradurga schist belt. Kibbanahalli volcanics are mainly tholeiites as distinct from the dominant komatiites of the JC Pura belt. Such chemical distinction, but of a different kind, is reported recently from the Kalasapura area of Bababudan belt. JC Pura area therefore offers yet another spectacle of Sargur-Dharwar orogenic discrimination in Kamataka.Keywords
Jayachamarajapura Greenstone Belt, Kibbanahalli, Komatiites, Angular Unconformity, Sargur-Dharwar Relationship, Geochemistry, Geochronology, Kamataka.- Presentation of Geochemical Data
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Authors
Affiliations
1 PPOD Division, AMSE Wing, Geological Survey of India, Bangalore-560082, IN
1 PPOD Division, AMSE Wing, Geological Survey of India, Bangalore-560082, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 47, No 6 (1996), Pagination: 751-752Abstract
No Abstract.- Carbonatite around Ajjipuram, Kollegal Taluk, Karnataka
Abstract Views :255 |
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Authors
T. R. Anantharamu
1,
K. N. Nagarna Rao
2,
Manjunatha
3,
Shafeeq Ahmed
4,
T. K. Gandhi Prasad
5,
T. Gopal Reddy
5,
S. P. Venkata Dasu
6,
E. B. Sugavanam
7
Affiliations
1 No.53, 9th 'E' Cross, S.B.I. Colony, J.P. Nagar I Phase. Bangalore -560078, IN
2 No. 693, Yelahanka, Bangalore- 560064, IN
3 No. 60, II main road, B.S.K. III Stage, III Phase, Bangalore-560085., IN
4 No.45/J, Marappa bLock,J. C. Nagar, Bangalore-560006, IN
5 Flat 202, Sandhyagiri Apartments, Kalyan Nagar, Hyderabad-500068, IN
6 7th Main, Padmanabhanagar, Bangalore- 560070, IN
7 54F, Venkatapuram, Shankernagar, Salem -636007, IN
1 No.53, 9th 'E' Cross, S.B.I. Colony, J.P. Nagar I Phase. Bangalore -560078, IN
2 No. 693, Yelahanka, Bangalore- 560064, IN
3 No. 60, II main road, B.S.K. III Stage, III Phase, Bangalore-560085., IN
4 No.45/J, Marappa bLock,J. C. Nagar, Bangalore-560006, IN
5 Flat 202, Sandhyagiri Apartments, Kalyan Nagar, Hyderabad-500068, IN
6 7th Main, Padmanabhanagar, Bangalore- 560070, IN
7 54F, Venkatapuram, Shankernagar, Salem -636007, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 46, No 6 (1995), Pagination: 663-668Abstract
Several lensoid bodies of carbonatite occur within a wide zone of fenitisation in the granulite terrain of Kollegal taluk, Karnataka. These are emplaced along deep NNE-SSW fracture system and are associated with pyroxenite, talc-tremolite schist showing varying degree of fenitisation. The sovite and beforsite varieties show high percentage of SiO2 due to contamination during emplacement The Fe20 3 , MnO and MgO values of Ajjipuram carbonatites broadly compare with the Koratti carbonatites occurring on the eastern part ofthe mobile belt with similar tectonic history.Keywords
Carbonatites, Kollegal Taluk, Karnataka.- Middle Archaean Age of Sargur Group by Single Grain Zircon Dating and Geochemical Evidence for the Clastic Origin of Metaquartzite from J. C. Pura Greenstone Belt, Karnataka
Abstract Views :193 |
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Authors
Affiliations
1 Geological Survey of India, Training Institute, Hyderabad, IN
2 Geological Survey of India, AMSE Wing, Bangalore, IN
3 Institut fuer Geowissenschaften, Johannes Gutenberg-Universitaet, 55099 Mainz, DE
1 Geological Survey of India, Training Institute, Hyderabad, IN
2 Geological Survey of India, AMSE Wing, Bangalore, IN
3 Institut fuer Geowissenschaften, Johannes Gutenberg-Universitaet, 55099 Mainz, DE
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 44, No 6 (1994), Pagination: 605-616Abstract
The middle Archaean J. C. Pura greenstone belt of Sargur Group underlies the Dharwar angular unconformity along the Kibbanahalli arm of Chitradurga schist belt. It consists essentially of periodotitic komatiite (serpentinite), basaltic komatiite (dark amphibolite), rare BIF and minor metaquartzite. In view of the ongoing debate on the origin of Sargur quartzite as to whether it is a chemogenic, biogenic or detrital-rich chert or quartz arenite, the study of J. C. Pura metaquartzite is important as it will have a direct bearing on the depositional setting of the metaquartzite in particular, and the Sargur association in general. In the absence of primary sedimentary structures, accessory zircons in the metaquartzite provide the main clue to its origin. Euhedral zircons with minor rounding of pyramidal terminations in the metaquartzite suggest little mechanical corrosion and negligible sedimentary transport. These zircons are interpreted as detrital grains and the host rock as siliciclastic in origin. Geochemical parameters like Al2O3 vs TiO2, SiO2 and K2O, trace element spider plots, REE patterns and La/Sc ratio indicate a significant continental contribution, low Fe and Mn content, low TiO2-normalised values and variable Co/Zn and Ni/Zn ratios preclude major sea water hydrothermal activity. The proximal provenance indicated by euhedral zircons did not apparently have a significant felsic volcanic component since such rocks are neither present witnin the schist belt nor found as enclaves in the surrounding gneisses. Furthermore, the Sr, Zn, Y, Yb values of the metaquartzite are lower than that of felsic volcanics and pyroclastics, thereby ruling out their prevalence in the source area. The most likely source would therefore be the widespread early Archaean continental crust of southern India made up of granitoids. The metaquartzite was probably deposited as quartz arenite in shallow marine enviroment close to the continent. The associated pillowed komatiite also lends support to this environmental interpretation.Euhedral zircons from J. C. Pura metaquartzite were dated by single grain evaporation technique which yielded a Pb-Pb age of 3230 ± 5 Ma. This date representing the maximum age of the Sargur metaquartzite is fully in accord with previous Sm-Nd model ages and SHRIMP U-Pb zircon ages (ca 3200 Ma) of Sargur rocks from nearby areas. The Sargur Group is pervasively intruded by gneisses and granites around 3000 Ma. Still older gneisses seen in the neighbourhood such as the Gorur gneiss of 3300 Ma age may constitute a possible basement to the Sargur supracrustals and represent widespread early Archaean granitic crust of the Dharwar craton.
Keywords
Geochronology, Geochemistry, Metamorphic Petrology, J. C. Pura/Sasivala Greenstone Belt, Sargur Group, Dharwar Craton, Kanataka.- Geological Field Notes and Sketches
Abstract Views :179 |
PDF Views:164
Authors
Affiliations
1 Geological Survey of India, AMSE Wing, Bangalore, IN
1 Geological Survey of India, AMSE Wing, Bangalore, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 54, No 2 (1999), Pagination: 214-214Abstract
No Abstract.- Geology and Tectonics of India: An overview
Abstract Views :183 |
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Authors
Affiliations
1 PPOD Division, AMSE Wing Geological Survey of India Bangalore - 560 078, IN
1 PPOD Division, AMSE Wing Geological Survey of India Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 68, No 2 (2006), Pagination: 327-328Abstract
No Abstract.- South African Journal of Geology - Kaapvaal Craton Special Volume
Abstract Views :189 |
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Authors
Affiliations
1 PPOD Division, AMSE Wing Geological Survey of India Bangalore - 560 078, IN
1 PPOD Division, AMSE Wing Geological Survey of India Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 4 (2005), Pagination: 523-525Abstract
No Abstract.- National Landslide Hazards Mitigation Strategy - a Framework for Loss Reduction
Abstract Views :161 |
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Authors
Affiliations
1 PPOD Division, AMSE Wing, Geological Survey of India, Bangalore - 560 078, IN
1 PPOD Division, AMSE Wing, Geological Survey of India, Bangalore - 560 078, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 3 (2005), Pagination: 384-385Abstract
No Abstract.- SGAT Bulletin
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Authors
Affiliations
1 AMSE Wing, Central zone, Geological Survey of India, Nagpur, IN
1 AMSE Wing, Central zone, Geological Survey of India, Nagpur, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 61, No 2 (2003), Pagination: 241-242Abstract
No Abstract.- Airborne Geophysical Surveys in Finland
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Authors
Affiliations
1 Airborne Mineral Surveys and Exploration Wing, Geological Survey of India, Bangalore - 560 078, IN
1 Airborne Mineral Surveys and Exploration Wing, Geological Survey of India, 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: 1120-1123Abstract
No Abstract.- The Geology of the Springbok Area
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Authors
Affiliations
1 AMSE Wing, Geological Survey of India, Bangalore, IN
1 AMSE Wing, Geological Survey of India, Bangalore, IN