Other than Central Petrological Laboratory at Headquarters, Kolkata, each region, all the three Wings and other State based operational units are having petrological laboratory, to cater to the needs of the various disciplines of earth science and also to carry out research on fundamental and applied aspects of igneous, sedimentary, metamorphic petrology, ore-mineralogy, coal petrography, clay mineralogy. Studies of meteorites are also being carried out in these laboratories. The recent induction of Cameca SX 100 EPMA equipment in the Central Petrological Laboratory has opened a new vista in the micro level analytical technique.
Central laboratories comprise of eight sub-units like rock cutting and section preparation, petrography lab, ore-microscopy unit, coal-petrography unit, sedimentological studies lab, clay mineralogy, fluid inclusion study lab, mineral separation lab and ultimately data processing unit. Regional and operational labs have facilities for study of rocks, ores and meteorites.
The laboratories delve in various fundamental problems as well as issues having direct societal impact. Detailed petrological, petrogenetic, geochemical, thermo-barometric, tectono-thermal, tectono-metamorphic, tectono-magmatic grain-scale deformation study, Ore petrography and fluid inclusion study, petrographic composition of coal seams, preliminary appraisal of the Coal bed methane content in coal seams, Petrographic and heavy mineral abundance studies, Mass balance studies, Study of the dune systems are dealt by these laboratories.
Research problems pursued in recent years include, study of granulites; study of alkaline rocks, which are known to originate at deep levels tapping the enriched asthenospheric mantle source and as such these yield valuable insights into mantle enrichment processes, magma generation, magmatic differentiation trends and emplacement history; study of higher Himalayan crystallines of Sikkim, study of volcanic rocks of Archaean greenstone belts and sedimentological studies of the lower reaches of the alluvial fans of the Gangetic delta.
GSI being the custodian of all Indian meteorites is engaged in the study of those for depicting the evolutionary history of different groups of meteorites. In collaboration with Smithsonian Institute, GSI has been able to establish the Lonar lake of Maharashtra, as a hypervelocity impact crater within mafic rocks. While working on Shergotty meteorite, in collaboration with NASA, it is established as one of the twelve Martian meteorites.
Services available:
Petrological laboratories provide various types of conventional and advanced petrological studies on commercial basis.
Preparation of polished slabs (max. size 10 cm X 6 cm).
Preparation of normal thin sections (TS), polished thin sections (PTS) and ore mounts.
Facilities for vacuum impregnation (equipment would be installed shortly) of rock chips that are soft, porous and fragile.
Preparation of oriented sections (for petrofabric studies).
Preparation of super polished sections (for SEM/ EPMA studies).
Preparation of grain mounts (for heavy mineral studies).
Separation of magnetic / non magnetic minerals using Isodynamic separator.
Separation of ferromagnetic, paramagnetic and diamagnetic minerals using Frantz Laboratory Magnetic Barrier Separator with low field control unit.
Separation of non- magnetic heavy minerals using Bromoform and other heavy liquids.
Petrographic study of rocks and minerals including ores.
Petrographic and geothermobarometric study using EPMA
Modal analyses of thin sections under microscopes (for quantitative estimation of mineral abundances).
Photography of hand specimens.
Microphotography of thin sections (both digital and using film roll).
Image analyses of thin sections and hand specimens.
Grain size analyses (up to fine silt or, 1/256 mm).
Determination of specific gravity of rocks and minerals.
Non- contamination grinding of rocks and minerals using agate and tungsten carbide pulverizer, to be installed shortly (for chemical analysis).
Data processing for cation calculation of minerals.
Data processing for CIPW norm calculation of rocks.
Data processing for petrographic variation diagrams.
Data processing for rock / chondrite normalization and REE plots.
Arrangement made for laboratory visit to school / college students on request from the institutions (subject to prior approved)
Fluorescence study of minerals using short- wave and long wave UV- radiation
Sand analyses, and heavy mineral studies, Gem Testing and testing of industrial diamonds
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