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Raghavan Nambiar, A.
- Pillow Structures in Meta Ultramafites of Wynad Schist Belt, Kerala
Authors
1 Geological Survey of India, Kerala Circle, Trivandrum 695014, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 23, No 10 (1982), Pagination: 514-516Abstract
No Abstract.Full Text
- Vengad Conglomerate of Wynad Schist Belt, Kerala
Authors
1 Geological Survey of India, Shillong 793003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 26, No 9 (1985), Pagination: 659-665Abstract
The Vengad Conglomerate is a basal polymict conglomerate, separating the high-grade Wynad Group of rocks from the low grade Vengad Group. The conglomerate along with the other members of the Vengad Group has undergone two phases of deformation and has attained lower amphibolite facies metamorphism. The petrography and chemistry of the pebbles and the matrix indicate the source area to be a mixed terrain consisting of tonalite-trondhjemite gneisses, mafic-ultramafic rocks, quartzites and quartz veins.
- Petrology of Lamprophyres from Parts of East Garo Hills and West Khasi Hills Districts, Meghalaya
Authors
1 Geological Survey of India, Mangalore 575 003, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 32, No 2 (1988), Pagination: 125-136Abstract
Lamprophyres occur as dykes and veins in the Precambrian gneisses and granitoid country rocks along and in the vicinity of tbe Nongchram Fault Zone in East Garo and West Khasi Hills Districts of Meghalaya. They arc genetically associated with feldsputhie ijolites, tinguaites and carbonatites. They are typically melanocratic and contain leucocratic ocelli, spherical or sub-spherical in shape with a centrally disposed core of carbonates and alkali feldspar, mica and clinopyroxene-rich lining. The carbonate-rich inner zones of these zoned ocelli are interpreted as space originally occupied by a gas phase, whereas the outer zones represent late stage liquids. The mineralogy and chemical parameters of these lamprophyres coupled with the common presence of ocelli and megacrysts of mafic minerals and their genetic association with sodic alkaline rocks and carbonatite classify them as alkaline lamprophyres. Petrographically, the holocrystalline rocks can be classified as camptonites and the chilled dyke margins as monchiquites.
The occurrence is suggestive of rift-related alkaline magmatism. These alkaline and related rocks together with the ultramafic-alkaline-carbonatite complex of Sung Valley may constitute an ill-defined alkaline province. Their genetic link with Sylhet Trap volcanics cannot be ruled out, as eruption of alkali basalts is generally followed by alkaline intrusions.
- Geomatics in Tsunami
Authors
1 Prashanthi, Devan Road, Kanhangad, Kerala - 671 315, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 67, No 6 (2006), Pagination: 813-815Abstract
No Abstract.Full Text