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61.
Bibhash Nath Sukumar Basu Mallik Doris Stüben Debashis Chatterjee Laurent Charlet 《Environmental Earth Sciences》2010,60(4):873-884
This study aims at finding out possible relation between lithology and spatial pattern of dissolved arsenic (As) in groundwater
around Chakdaha municipality, West Bengal, India. Satellite image, coupled with electrical resistivity survey and borehole
drilling helps to delineate surface and sub-surface lithological framework of the As affected alluvial aquifers. The satellite
imagery demonstrate that the high As area are presumably under active flood plain environment (low-lying areas), that constantly
receive organics due to periodic flooding. Thick low resistive (fine-grained) layer was observed at the top around the high
As areas, which, however, not found in low As areas. The result suggests that hydraulic properties of the surface/sub-surface
soil/sediment have an important control on the fate and transport of As in the aquifer. This study demonstrates that electrical
resistivity tools can be effectively used for the reconnaissance survey in characterizing the plausible lithological framework
of an alluvial aquifer containing As. 相似文献
62.
Locally recorded data for eighteen aftershocks of a magnitude(mb) 4.6 earthquake occurring near Ukhimath in the Garhwal Himalaya were analysed. A master event technique was adopted to locate
seventeen individual aftershock hypocentres relative to the hypocentre of the eighteenth aftershock chosen as the master event.
The aftershock epicentres define an approximately 30 km2 rupture zone commensurate with the magnitude of the earthquake. The distribution of epicentres within this zone and the limited
amount of first motion data support the view that a group of parallel, sub-vertical, sinistral strike-slip faults oriented
N46°, transverse to the regional NW-SE trend of the Garhwal Himalaya, was involved in this seismic episode. Since the estimated
focal depth range for aftershocks of this sequence is 3–14 km, we infer that this transverse fault zone extends through the
upper crustal layer to a depth of 14 km at least. 相似文献
63.
Dr. Niranjan D. Chatterjee 《International Journal of Earth Sciences》1964,53(2):536-550
Tectonic analysis within the Mesozoic sequence of the Pennine belt in the vicinity of the northern Dora-Maira massif resulted in the discovery of three different B-axes of Alpine age:
- 1.The oldest one with NNW-trending axes is found to have been developed exclusively to the south and west of the Ambin massif, followed by 相似文献
64.
The use of LANDSAT data has proved to be a major aid to semi-macroscale geomorphic mapping of terrain. The geomorphological contribution to the classifications of the Darjeeling District, using quantitative measures of selected terrain factors apart from conventional landsystem mapping on MSS-imagery, has been found to be more useful means of terrain evaluation as well as its proper development in resource management. Qualitative estimates of terrain factors, viz. altitude, relief, slope and dissection nature, drainage texture and pattern, valley forms and crest types coupled with landcover types etc. are considered in preparation of landsystem map of the area. Because of its subjective biasness, an alternative approach, the parametric method of terrain classification is carried out to analyse the spatial distributions of quantitative parameters on terrain factors viz. maximum altitude, average altitude, relative relief, average slope, dissection index, drainage density and ruggedness index etc. and to combine the resulting patterns into compositive generalizations. The composite map thus prepared reveals six terrain units of distinct morphological classes and are sufficiently equatable to certain physical conditions of terrain. 相似文献
65.
66.
S. N. Chatterjee 《Pure and Applied Geophysics》1971,86(1):69-79
Summary Propagation of Rayleigh waves in a layer lying over a heterogeneous incompressible half space has been studied. The dispersion equations have been derived and displacements due to an infinite line source have also been investigated. 相似文献
67.
Summary Torsional vibration of a body composed of two conical bars, the upper one being made of non-homogeneous material and the lower of a homogeneous material, by the application of a shearing stress on the upper end has been considered in the problem. It is assumed that the lower end of the composite body is fixed and the lateral surface is free from shearing stress. 相似文献
68.
Niranjan D. Chatterjee 《Contributions to Mineralogy and Petrology》1972,34(4):288-303
The assemblage paragonite + quartz is encountered frequently in low- to medium-grade metamorphic rocks. With rising grade of metamorphism they react mutually to yield the condensed assemblage albite + Al2SiO5.The univariant curve pertaining to the equilibrium paragonite + quartz=albite + andalusite + H2O has been located experimentally. The reversed P
H
2
O-T data are: 1 kb: 470–490° C 2 kb: 510–530° C 3 kb: 540–560° C 4 kb: 560–580° C 5 kb: 590–600° C The univariant curve pertaining to the equilibrium paragonite + quartz=albite + kyanite + H2O runs through the following P
H
2
O-T-intervals: 5 kb: 570–625° C 6 kb: 600–630° C 7 kb: 620–640° C Thermodynamic calculations of S
298
0
, H
f,298
0
and G
f,298
0
of the phase paragonite from the experimental data presented above and those obtained from the equilibria of the reaction paragonite=albite + corundum + H2O (Chatterjee, 1970), agree within the limits of uncertainty. This prompts the idea that Zen's (1969) suggestion of a possible error of approximately 7 kcal in G
f,298
0
of the Al2SiO5 polymorphs may in fact be due to an error of similar magnitude in G
f,298
0
of corundum.A best estimate of S
298
0
, H
f,298
0
and G
f,298
0
of paragonite based on these considerations yield: S
298
0
: 67.61±3.9 cal deg–1 gfw–1
H
f,298
0
: –1411.4±2.7 kcal gfw–1
G
f,298
0
: –1320.9±4.0 kcal gfw–1 These numbers will be subject to change when better thermochemical data on corundum and albite are available.In medium-grade metamorphic rocks the assemblage paragonite + quartz is commonly found in stable coexistence with such other phases as muscovite, staurolite, andalusite, kyanite, but not with cordierite or sillimanite. However, the assemblage paragonite-sillimanite has been reported to be stable in the absence of quartz. All these petrologic observations can be explained on the basis of the stability data of the phases and phase assemblages concerned. 相似文献
69.
The univariant pressure temperature curve of the reaction aluminous enstatite solid solution+sillimanitesapphirine solid solution+quartz was determined experimentally in the pressure range between 12 and 20 kb. It is defined by four reversals at 15 kb, 1140°+10°C; at 1190°C, 15.9±1 kb; at 1300°C, 17.2±1 kb; and at 1400°C, 18±1 kb. Among the coexisting phases the Al-content of the enstatites increases strongly, with rising temperatures and pressures, up to values approaching that of pyrope composition, whereas the Al-content of the sapphirine solid solution appears to increase only slightly. Concomitantly, the sillimanites, most probably of invariant composition, exhibit growing Al/Si-disorder. These compositional and structural variations, in addition to the changing stoichiometry of the reaction equation, cause the progressively decreasing positive dP/dT slope of the equilibrium curve. — The assemblage sapphirine + quartz found in natural granulites is indicative of conditions of water pressure much lower than total pressure. 相似文献
70.
D. Chatterjee 《Pure and Applied Geophysics》1970,82(1):34-40
Summary The expressions for stresses and extension have been obtained in an isotropic circular cylinder in a state of plane strain, the elastic constants and the density of the material varying exponentially and the results have been compared with those in the homogeneous case. 相似文献