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The technique of linear digital filtering as developed for the direct interpretation of Schlumberger and Wenner soundings (Ghosh 1971) has been applied here for the derivation of the resistivity transform function from the field dipole measurements as the first step in directly interpreting dipole data. Filter coefficients for this transformation have been worked out for the radial-polar, perpendicular and parallel (30°) arrays of dipole sounding. The procedure combines speed with accuracy. 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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Tidal variations in the Sundarbans Estuarine System, India 总被引：1，自引：0，他引：1
MEENAKSHI CHATTERJEE D SHANKAR G K SEN P SANYAL D SUNDAR G S MICHAEL ABHISEK CHATTERJEE P AMOL DEBABRATA MUKHERJEE K SUPRIT A MUKHERJEE V VIJITH SIDDHARTHA CHATTERJEE ANWESHA BASU MADHUMITA DAS SARANYA CHAKRABORTI ARAVIND KALLA SURJA KANTA MISRA SOUMYA MUKHOPADHYAY GOPAL MANDAL KANKAN SARKAR 《Journal of Earth System Science》2013,122(4):899-933
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Northeast India region is one of the most seismically active areas in the world. Events data for the period 1897–2010, used
in this study has been largely compiled from global ISC, NEIC and GCMT databases. Historical seismicity catalogue of Gupta
et al (1986) and some events data from the bulletins of India Meteorological Department are also used. Orthogonal regression relations
for conversion of body and surface wave magnitudes to M
w,HRVD based on events data for the period 1978–2006 have been derived. An Orthogonal Standard Regression (OSR) relationship has
also been obtained for scaling of intensity estimates to M
w,NEIC using 126 global intensity events with intensity VI or greater during the period 1975–2010. 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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Nature of light rain during presence and absence of bright band 总被引：1，自引：0，他引：1