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Chatterjee, A. K.
- The Structural Set up of Apart of the Malangtoli Iron Ore Deposit, Orissa
Authors
1 National Mineral Development Corporation, Pioneer House, Somajiguda, Hyderabad 500004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 22, No 3 (1981), Pagination: 121-130Abstract
The paper describes the localisation of iron ore bodies in the Malangtoli group forming the southeastern end of the Bonai Synclinorium comprising Singhbhum-Keonjhar-Sundergarh group of iron formations. Three fold systems affect the area. Barring a few instances which are due to facies changes, the overall pattern of Occurrence of iron ore bodies is fairly conformable with the tectonic set up and the behaviour of such ore bodies are continuous with the structural pattern. The distribution of iron ore body/bodies in space is/are controlled by the superposed fold systems, the ore body reaching maximum depths in structural basins and/or canoes and minimum depths (occasionally base rock outcropping) in structural highs, i.e., domes and inverted canoes. Certain conclusions arising out of this are analysed.
- Majhgawan Diamondiferous Pipe, Madhya Pradesh, India - A Review
Authors
1 National Mineral Development Corporation Ltd., Hyderabad-500 028, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 45, No 2 (1995), Pagination: 175-189Abstract
The alkaline ultrabasic diatreme at Majhgawan has an idealised geological setting being intruded into the platformal Kaimur sandstones of the Lower Vindhyan Supergroup (1400-1100 Ma) overlying cratonic Bundelkhand granite basement (2550 Ma) which is a typical archon as per Janse (1992). Recent Rb/Sr age data indicate 1042 Ma (Smith 1992) and 1067 Ma (Anil Kurnar and Gopalan 1992) for the Majhgawan pipe. The pipe with surface dimension of 500 × 320 m is a carrot shaped body reminiscent of a typical kimberlite with minimal erosion. The pipe rock has been classified as lamproite by Scott Smith (1989, 1992a) who has termed it as olivine lamproitic lapilli tuff of crater facies. High TiO2(4-6%), less abundance of typical heavy indicator minerals (HIM) like group-10 pyrope garnet and ilmenite and overall petrological characters of the pipe strongly reflect lamproite nature. High amounts of certain minor elements such as Ba (3000 ppm), Sr (1000 ppm) and REE (high La, U/Th ratio) also indicate its lamproitic character.On the other hand the typical carrot shape of the plug, almost concentric distribution of diamonds, mode of presence of mantle-derived xenocrysts, overall chemistry with high MgO(25%) low K2O(1%) and fair amounts of Cr and Ni are highly characteristic of kimberlitic nature. Broad petrographic characters coupled with abundance of xenocrysts and occurrence of country rock xenoliths and geochemical charecteristics suggest it is in several aspects typical kirmberlite rather than lamproite. The garnet population with fair amount of harzburgitic pyrope and larger share of lherzolitic variety indicate characteristics almost intermediate between kimberlite and lamproite.
Irrespective of the nature of the diatreme in any exploration model for search of new primary sources in the area, the spesific nature of HIM of the Majhgawan rock has to be kept in view (i.e.rather less abundance of garnet that too more of group-9 type, predominance of high magnesia spinellchromite, absence of ilmenite etc). The Majhgawan diamonds (42% gem) are predominantly curve faced modified forms indicating signs of resorption.
Keywords
Kimberlite, Lamproite, Diamond, Majhgawan, Panna, Madhya Pradesh.- Geothermometry and Oxygen Barometry of Coexisting Iron-Titanium Oxides of Majhgawan Diamondiferous Pipe, Madhya Pradesh
Authors
1 National Mineral Development Corporation Ltd., Khanij Bhawan, Masab Tank, Hyderabad-500028, IN
2 Department of Applied Geochemistry, Osmania University, Hyderabad-500007, IN
3 302-Expresso Apts., Lakdikapool, Hyderabad-500004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 49, No 1 (1997), Pagination: 55-60Abstract
Geothermometry of the coexisting magnetite-ilmenite (Mt-Ilm) pair from Majhgawan diamondiferous pipe indicates a temperature of 1150°C. The values of fO2 T and P fall in the equilibria field defined by iron-wustite (IW) and wustite magnetite (WM) indeating depth of sampling of about 155km and pressure of 46kbar.Keywords
Geothermometry, Geobarometry, Fe-Ti-Oxides, Majhgawan Pipe.- Chemistry of Phlogopite Megacrysts in Majhgawan Diamondiferous Pipe, Panna, Madhya Pradesh
Authors
1 National Mineral Development Corporation Limited, Khanij Bhawan, Castle Hills, Masab Tank, Hyderabad-500028, IN
2 302, Expresso Apts., Lakdika Pool, Hyderabad-500004, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 49, No 2 (1997), Pagination: 203-206Abstract
The phlogopite megacrysts of Majhgawan diatreme have been grouped into two groups and from the inspection of the chemical analysis of micas their origin are discussed.Full Text
