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141.
O. P. Pandey 《Journal of the Geological Society of India》2009,74(5):615-624
Indian shield has been frequented by number of large and moderate magnitude damaging earthquakes since historical times, including
the recent disastrous ones like Latur Mw 6.3 in 1993, Jabalpur Mw 5.8 in 1997 and Bhuj Mw 7.7 in 2001. Seismogenesis of these
events is still not understood well. Detailed study of nine such earthquake localities (as appended in Table 1), indicates
quite high P- and S- velocities (6.2–6.7 km/s and 3.65–3.90 km/s respectively) at a shallow depth of almost surface to six
kilometers. These seismogenic regions appear to be in a state of continuous uplift and erosion since geological times, which
brought mafic (granulitic/amphibolitic) crust to significantly shallow levels in which stresses are accummulated due to ongoing
local uplift and a high input of heatflow from the mantle. These stresses act over and above to the regional compressive stresses
generated by India-Eurasia collision. As against common belief, the role played by fluids in nucleation of such earthquakes,
in the relatively denser and high velocity Indian crust (compared to the other global stable continental regions), appears
limited. 相似文献
142.
Jai Krishna Bindhyachal Pandey Deo Brat Pathak 《Journal of the Geological Society of India》2009,74(4):469-479
We report here the first Dichotomoceras of the Indian subcontinent at Kantkote (Wagad) in the proximal most exposed part of the Kachchh Basin. This is further addition
to the significant enlargement of the Oxfordian ammonoid record made earlier (Krishna et al. 1994, 1995, 1998, 2000). Near
continuous presence of ammonoids has been recorded in ca 55 m thick succession, almost immediately above the Schilli Subzone,
that was considered ammonoid devoid earlier. The ammonoid density, diversity and frequency in this just discovered ca 55 m
thick column are much scarcer in comparison to the underlying 10 m thick ammonoid abundant Schilli Subzone.
Examples of Dichotomoceras are determined almost throughout the said interval which in our preliminary taxonomic evaluation appear identical or close
to D. rotoides (Ronch.), D. stenocycloides (Siem.), D. bifurcatus (Quenst.) and D. crassus Enay. It thus suggests the characterization of the Rotoides Subzone of the Transversarium Zone and the superjacent Bifurcatus
Zone of the column at least up to the early Late Oxfordian. 相似文献
143.
Sandipan Mukherjee Ravi Prakash Shukla Ashok Kumar Mittal Avinash Chandra Pandey 《Meteorology and Atmospheric Physics》2011,114(3-4):83-93
Mathematical analysis of a predominantly bimodal chaotic attractor, Lu system, was carried out to investigate a possible application of the model as a prototype of monsoon intra-seasonal oscillation (ISO). Bifurcation structures of the system are explored as the system parameter c and the forcing parameter F are varied. Stability criteria of equilibrium points of the forced Lu system are also explored in detail. A sensitivity study is carried out, by changing forcing parameter F, to explore relationships between some of the derived variables of the model and, based on such relationships, an empirical rule is used for extended range prediction. Analogous variables are also derived from the ISO data and prediction results are compared. Application of the prediction rule of regime transition to the observed ISO and chaotic model data is purely based on the bimodal characteristics of ISO and neglects some of the intricate mechanisms therein. We have found that a forced Lu system can be a good prototype in the prediction of peak anomaly of the monsoon ISO when growth rates around a threshold value are taken as predictors. 相似文献
144.
The Paleocene-recent post-rift subsidence history recorded in the Mumbai Offshore Basin off western continental margin of India is examined. Results obtained through 2-D flexural backstripping modelling of new seismic data reveal considerable thermo-tectonic subsidence over last ca. 56 Myr. Reverse postrift subsidence modelling with variable β stretching factor predicts residual topography of ca. 2000 m to the west of Shelf Margin Basin and fails to restore late Paleocene horizon and the underlying igneous basement to the sea level. This potentially implies that:(1) either the igneous basement formed during the late Cretaceous was emplaced under open marine environs; or(2) a laterally varying cumulative subsidence occurred within Mumbai Offshore Basin(MOB) during ca. 68 to ca. 56 Ma. Pre-depositional topographic variations at ca. 56 Ma across the basin could be attributed to the extensional processes such as varied lower crustal underplating along Western Continental Margin of India(WCMI). Investigations about basement tectonics after unroofing of sediments since late Paleocene from this region support a transitional and heavily stretched nature of crust with high to very high β factors. Computations of past sediment accumulation rates show that the basin sedimentation peaked during late Miocene concurrently with uplift of Himalayan-Tibetan Plateau and intensification of Indian monsoon system. Results from basin subsidence modelling presented here may have significant implications for further studies attempting to explore tectono-climatic interactions in Asia. 相似文献
145.
A. K. Awasthi A. K. Pandey J. Khan 《International Journal of Environmental Science and Technology》2017,14(4):729-742
Municipal solid waste poses a risk on surrounding environment and public health, mainly because of unscientific disposal and shortage of facilities for proper handling and recycling of leachate. This research article objective is to pinpoint the indigenous fungal isolates of waste leachate samples. Therefore, we carried out biosorption of Cd2+ tested the applicability by applying indigenous fungal isolates. The limited number of fungal isolates was found based on their ability for biosorption of Cd2+ metal. The fungal strains Trichoderma sp., Aspergillus niger and Aspergillus flavus were reported as potential strains for metal exclusion ability from the leachate. Among them, the Trichoderma sp. was found as excellent fungal agent for Cd2+ absorption. The optimum pH was 5.5 ± 1, temperature 45 °C, and spore concentration 10?5 to achieve the maximum biosorption, and 35 days of incubation period were required by three strains. The maximum metal biosorption achieved was comparable for the three isolates: 56.34% by Trichoderma sp., 44.74 and 42.04% by A. niger and A. flavus, respectively. Concluding, the further intending application to identified potentially fungal isolates is able to improve the efficiency of metal biosorption. These strains are recommended for development of consortia could become a best technique for MSW leachate treatment if its reliability and applicability should be verified prior to technology acceptance. 相似文献
146.
Jitendra Pandey Dheeraj Kumar D. C. Panigrahi V. K. Singh 《Environmental Earth Sciences》2017,76(12):439
Coal is dominant energy source of world at large and India in particular for several decades and expected to being continued for foreseeable future. However, fire in this fossils fuel is still a global catastrophe for the major coal-producing countries. There are several direct and cascading distress of coal mine fire has been encountered by environment, economy, safety and society. Without knowledge of actual status and extent of coal mine fire, any scope for its better managements may be futile. In India, the coal mine fire of well-known Jharia coalfield (JCF) has been continued since last ten decades and still spreading towards newer areas. The aim of this paper is to highlight the chronological net lateral spatial changes in coal mine fire areas of JCF using Landsat satellite thermal imageries. The mapping of coal mine fire area of JCF during 1988–2013 has been carried out with consecutive 5-year intervals. The lateral changes in surface and subsurface fire areas along with propagation towards new area have been studied. The study also included to evaluate changes of status and extent fire during this time span and effect of its management efforts. On the basis of aforementioned analysis, the study concludes a slow reducing trend in coal mine fire area during last 25 years. 相似文献
147.
Vimal Chandra Pandey Jay Shankar Singh Akhilesh Kumar D. D. Tewari 《洁净——土壤、空气、水》2010,38(12):1116-1123
Chickpea grown in fly ash (FA) treated soil (25, 50, and 100% FA) was used to evaluate the effect of FA on antioxidants, metal concentration (Fe, Zn, Cu, Cr, and Cd), photosynthetic pigments (chlorophyll a (chl‐a), chlorophyll b (chl‐b), total chlorophyll (total chl), and carotenoids), growth and yield performance. All antioxidants in roots, shoots and leaves of chickpea increase with increasing FA doses to combat FA stress. The activities of antioxidants were more in the root tissues to cope with stress induced in the plants as compared to shoot and leaf. Concentration of metals was found maximum in roots than the shoots and seeds. The highest concentration of Fe and lowest level of Cd were recorded in all treatments of FA for different parts of the plant. The treated crop showed reduced level of chlorophyll but enhanced level of carotenoids and protein. However, root length, number of nodules and biomass in 25 and 50% FA treatments did not differ significantly in comparison to respective control plants. These results suggest that heavy metals of FA causes oxidative stress in this crop and the antioxidant enzymes could help a pivotal role against oxidative injury. 相似文献
148.
Surface-level moisture transport over the Indian Ocean has been computed using NOAA/HIRS data for the years 1980, 1981 and 1984. The global relation between monthly mean surface-level humidity and precipitable water (Liu, 1986) has been applied for the computation of surface-level humidity using monthly mean satellite-derived water vapour. The monthly mean surface wind fields over the Indian ocean provided by Florida State University have been used for the surface-level moisture flux computations. Our analysis indicates net positive surface-level moisture flux divergence over the Arabian Sea and negative moisture flux divergence over the Bay of Bengal. It has also been found that evaporation over the Arabian Sea is a variable quantity and forms a significant part of the net moisture budget over the Arabian Sea. The relative contribution of cross-equatorial flux and evaporation from the Arabian Sea has been studied for all three years. 相似文献
149.
Waterlogging and flood hazards vulnerability and risk assessment in Indo Gangetic plain 总被引:2,自引:2,他引:2
The recurrent flooding during monsoon and subsequent waterlogging in the northern Bihar plains and the magnitude of losses
due to these hazards indicate the continuing vulnerability of the region to flood and waterlogging. Management of floods and
waterlogging hazards in highly flood-prone regions of India, including Bihar state has been largely response oriented with
little or no attention to mitigation and preparedness. This paper presents a method for spatial, Geographic Information Systems-based
assessment of flood and waterlogging vulnerability and risk in northern Bihar plains. Multitemporal satellite data was used
to evaluate the area statistics and dynamics of waterlogging over the period from 1975 to 2008. The flood proneness is evaluated
at district level with reference to flood inundation during a period from 1998 to 2008. Census data were used to examine the
socio-economic characteristics of the region through computation of population density, cultivators, agricultural labourers,
sex ratio, children in age group 0–6 years and literates. The geohazard map derived by combining area prone to waterlogging
and flood inundation was multiplied with socio-economic vulnerability map to derive the flood-waterlogging risk map of the
region. The result shows that flood and water-logging pose highest risk to the central districts in the northern Bihar plains
with 50.95% of the total area under high and very high risk. 相似文献
150.
Madhuparna Roy Shailendra Kumar Pradeep Pandey C. L. Bhairam P. S. Parihar 《Journal of the Geological Society of India》2014,84(4):377-384
The circular structure at Mohar (Dhala structure) in the western part of Bundelkhand Gneissic Complex, is marked by a prominent outlier of Kaimur sediments surrounded by low lying concentric sequence of sediments of Dhala Formation and basement granite breccia. This has been interpreted as a volcanic eruption related cauldron structure and meteoritic impact crater structure by various authors, on the basis of absence or presence of shock indicators in the clasts of a rhyolite-like rock that crops out scantily in the north western part of the structure. During the course of extensive sub-surface uranium exploration in this structure, the geoscientists of Atomic Minerals Directorate for Exploration and Research observed unequivocal and rampant evidences of shock metamorphic features for the first time in drill core samples of basement granitoids which constitute the bed rock for the rhyolite-like melt breccia, which overlies it. Published data of shock metamorphic features from this area are largely confined to the surface samples of the rhyolite-like melt rock, exposed in sparse outcrops. The shock metamorphic features recorded in the sub-surface granitoid bed rock samples during the present study, comprise planar deformation features (PDF) in quartz, feldspar, apatite and zircon, toasted, diaplectic, ladder-textured feldspars, selectively shock-melted feldspars and melt-veined quartz. The shock metamorphic features recorded in surface and sub-surface samples of the melt rock include ballen quartz, PDF in quartz clasts, toasted and diaplectic feldspar clasts shocked basic rock fragments with isotropised feldspars. Both the shocked bedrock granitoid and the melt rock bear uncharacteristic geochemical signatures with elevated K2O, MgO and depleted CaO. The study also observes that the melt breccia overlying the granitoid bedrock also occurs as pocket-like patches at various depths within the granitoids. Thus, the present findings have helped in understanding the attributes of the basement granitoid and associated melt breccia, thereby linking the genesis of the latter by selective melting of the former, due to the process of impact. It reinforces the already propounded theory of impact as the likely cause for the development of the structure in the basement Bundelkhand granitoid that was later filled by sediments standing out presently as a mesa. 相似文献