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E.K.KRISHNA KUMAR S.ABHILASH SANKAR SYAM P.VIJAYKUMAR K.R.SANTOSH A.V.SREENATH 《大气科学进展》2023,40(4):697-710
The inverse relationship between the warm phase of the El Ni?o Southern Oscillation(ENSO) and the Indian Summer Monsoon Rainfall(ISMR) is well established. Yet, some El Ni?o events that occur in the early months of the year(boreal spring) transform into a neutral phase before the start of summer, whereas others begin in the boreal summer and persist in a positive phase throughout the summer monsoon season. This study investigates the distinct influences of an exhausted spring El Ni?o(springtime)... 相似文献
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H.B. DESAI S.R. KAYASTH C.G. UDAS M. SANKAR DAS 《Geostandards and Geoanalytical Research》1983,7(2):325-329
The reported values for the chromium contents of standard acidic rocks show a large spread, making it difficult to assign firm recommended values. A radiochemical neutron activation analysis procedure was developed and its reliability examined critically. The method involves separation of chromium as chromyl chloride by distillation followed by precipitation as barium chromate. The chromium content of a number of international standard rocks has been determined and results obtained are critically reviewed in relation to the available data. 相似文献
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KAUSHIK DAS SANKAR BOSE SUBRATA KARMAKAR SUPRIYA CHAKRABORTY 《Journal of Earth System Science》2012,121(1):1-17
Granulite-facies rocks occurring north-east of the Chilka Lake anothosite (Balugan Massif) show a complex metamorphic and
deformation history. The M1–D1 stage is identified only through microscopic study by the presence of S1 internal foliation shown by the M1 assemblage sillimanite–quartz–plagioclase–biotite within garnet porphyroblasts of the aluminous granulites and this fabric
is obliterated in outcrop to map-scale by subsequent deformations. S2 fabric was developed at peak metamorphic condition (M2–D2) and is shown by gneissic banding present in all lithological units. S3 fabric was developed due to D3 deformation and it is tectonically transposed parallel to S2 regionally except at the hinge zone of the F3 folds. The transposed S2/S3 fabric is the regional characteristic structure of the area. The D4 event produced open upright F4 folds, but was weak enough to develop any penetrative foliation in the rocks except few spaced cleavages that developed in
the quartzite/garnet–sillimanite gneiss. Petrological data suggest that the M4–D4 stage actually witnessed reactivation of the lower crust by late distinct tectonothermal event. Presence of transposed S2/S3 fabric within the anorthosite arguably suggests that the pluton was emplaced before or during the M3–D3 event. Field-based large-scale structural analyses and microfabric analyses of the granulites reveal that this terrain has
been evolved through superposed folding events with two broadly perpendicular compression directions without any conclusive
evidence for transpressional tectonics as argued by earlier workers. Tectonothermal history of these granulites spanning in
Neoproterozoic time period is dominated by compressional tectonics with associated metamorphism at deep crust. 相似文献
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ADITI MANDAL ARIJIT RAY MAYUKHEE DEBNATH SANKAR PRASAD PAUL 《Journal of Earth System Science》2012,121(3):793-812
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Last glacial hydrological variations at the southern margin of sub‐tropical North America and a regional comparison 
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M. SANKAR DAS 《Geostandards and Geoanalytical Research》1979,3(2):199-205
Trace element data compiled on, geoshemical reference samples present invariably skewed distributions. It is proposed to treat such data as lognormally distributed and to compute geometric means (Xgm ) as probable values. As examples, the Xgm values derived for some trace elements in some rock reference samples are compared with the "recommended" values and with the "gamma" values of Christie. 相似文献
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The delayed fission neutron counting method has been used for the analysis of thirty-three international geochemical reference samples for their uranium contents in the range of 0.2 to 1500 ppm. These include three from the Canada Centre for Mineral and Energy Technology, three from Atomic Energy Commission, USA, New Brunswick Laboratory, two from Bhabha Atomic Research Centre, India, fourteen from Centre de Recherches Pétrographiques et Géochimiques and eleven from US Geological Survey. The experimental set up has a detection limit of 0.08 μg and a determination limit of 0.15 μg U. At the lower limit the precision of determination is about 20 percent while at concentrations higher than 1 ppm it is better than 10 percent. 相似文献
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