Records of the Geological Survey of India, Volume 115, Parts 3-4The Survey, 1987 - Earthquakes Vols. 1- include Report of the Geological Survey, 1867- ; v. 32- include Review of the mineral production of India, 1898/1903- ; v. 75 consists of Professional papers, no. 1-16; v. 76 consists of Bulletins of economic minerals. |
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Page 29
... grains show 2V , as low as 10 ° ; these grains may be sanidine . Nepheline which occurs as euhedral crystals are either hexagonal , rectangular or square shaped under microscope . It is characteristically altered to zeolites ...
... grains show 2V , as low as 10 ° ; these grains may be sanidine . Nepheline which occurs as euhedral crystals are either hexagonal , rectangular or square shaped under microscope . It is characteristically altered to zeolites ...
Page 48
... grains are mostly aligned along the S - surface though a few grains transverse to it are also present . Epidote and opaques occur as accessories . Opaques inclu- de mainly sulphides ( pyrite , chalcopyrite ) and oxides ( magnetite ) ...
... grains are mostly aligned along the S - surface though a few grains transverse to it are also present . Epidote and opaques occur as accessories . Opaques inclu- de mainly sulphides ( pyrite , chalcopyrite ) and oxides ( magnetite ) ...
Page 49
... grain boundaries . Plagioclase ( albite ) grains , occur in the interstices of hornblende grains ; both twinned ( Carlsbad type ) and untwinned grains show clouding and seri- citisation . Euhedral to subhedral epidote grains show ...
... grain boundaries . Plagioclase ( albite ) grains , occur in the interstices of hornblende grains ; both twinned ( Carlsbad type ) and untwinned grains show clouding and seri- citisation . Euhedral to subhedral epidote grains show ...
Contents
A NOTE ON THE EVOLUTION OF THE MINERAL | 17 |
Pant | 24 |
A R Nambiar | 43 |
Copyright | |
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aegirine alkaline rocks Arunachal Pradesh assemblage Barail Range bedded biotite borehole Brahmaputra camptonites carbonatite Chalcopyrite charnockite chlorite Coal cordierite deposits Disang dissected hills drainage dyke Evans feldspar feldspathic ijolite flood plain foliation fractured garnet Geol GEOLOGICAL SURVEY gneiss Golagar basin Golagar Nala grains GSI Rec 115 Hills district Himalaya ijolite immiscibility Indravati river inner belt Kohima Kohima synclinorium Kopili Koraput lamprophyres landforms magma magnetite Manipur Meghalaya metamorphic metapelites Mikir hills mineral mineralised zone muscovite Nagaland Nala Naogaon Naogaon Sandstone NE-SW occur Orissa orthoclasite phenocrysts Phyangla Plate point bar polymetallic porphyroblasts Potin Formation pyrite pyrrhotite quartz Ranga River Ranga Valley Rec 115 pts region ridge and valley samples San Nala sandstone schist shale Shillong staurolite Structural Plateau Subansiri district sulphide mineralisation Surma Surv SURVEY OF INDIA synclinorium tectonic Tikak parbat tinguaite trending tributaries type area Umrong reservoir units Upper Assam upto