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The objective of the present study was to delineate temporal and spatial changes in the coal fire and land use/cover within Bastacolla area of Jharia coal field. Studying this variation helped to decipher interconnection among the dynamics of the coal fire and concomitant changes in land use/cover. The detection of coal fires during a span of 14 years along with transitioning land use/cover was cost-effective and enabled planning for management of coal resources and environment. Landsat series of satellite data of 2002, 2009, 2013, and 2016 were processed for generating land surface temperature profiles vis-a-vis classified land use/cover of the study area. A single cut-off temperature was derived for mapping of coal fires using land surface temperature profile from 2002 to 2016. The satellite images were classified using support vector machines, and for depicting land use/cover change, post-classification change detection was done. Classification accuracy obtained was excellent with kappa coefficient ranging from 0.897 for classified image of 2002 to 0.799 for classified image of 2016. Results revealed that coal fires had shifted to the central west part of the area. Furthermore, pockets of coal fire from northern and eastern part of the study area have diminished. OB dumps and coal quarry/coal dump may be attributed towards the spatial change in coal fire while; OB dumps showed connotation with the highest temperature zones. Ground verifications for temperature profiles and coal fires were carried out using thermal camera which enunciated good agreement with results.  相似文献   
2.
Granitic plutons occurring within and to the west of the Delhi Fold Belt in the Aravalli craton, northwestern India are the result of widespread felsic magmatism during Neoproterozoic, some of which are associated with greisen and skarn tungsten deposits. In this paper, we present the result of our study on fluid inclusions, geochemistry and geochronology of two such tungsten mineralized granite plutons at Degana and Balda, and interpret the nature of ore fluid, and petrogenesis and age of these mineralized granites. Fluid inclusion study reveals coexistence of moderate and hyper-saline aqueous fluid inclusions along with aqueous-carbonic inclusions, suggesting their origin due to liquid immiscibility during fluid–rock interaction. Geochemically, the granites are peraluminous, Rb enriched, Sr and Ba depleted and highly differentiated. The Rb–Sr isotopic systematics yielded \(795\pm 11\) Ma for Balda granite and \(827\pm 8\) Ma for Degana granite. We show that major phase of widespread granitoid magmatism and mineralization during the Neoproterozoic (840–790 Ma) in NW India is coeval with breakup of the Rodinia supercontinent and infer a causal relationship between them.  相似文献   
3.
Formation conditions of orebodies and conditions of wolframite deposition at the Degana tungsten deposits in Rajasthan, India and the Tigrinoe tin-tungsten deposit in the Russian Far East were studied. Differences in the composition and state of fluid systems were established by microthermometric study of fluid inclusions (FI) and thorough petrographic examination of FI. At the Degana deposit, the ore veins in granite were formed from K-Na-Ca-(Mg, Fe, etc.) chloride solutions with a salinity up to 36 wt % NaCl equiv at a temperature of >420 to 120°C and under a pressure reaching 1550 bar. The formation temperature of the orebodies hosted in breccia reached 450°C and pressure was below 400 bar. The salinity of mainly Nachloride aqueous solutions was no higher than 18 wt % NaCl equiv. At the Tigrinoe deposit, the temperature during formation of quartz-wolframite-cassiterite veins varied from 420 to 240°C and the pressure was no higher than 300 bar. The salt concentration of Na-chloride solutions was 7-3 wt %. Wolframite crystallized at the very beginning of ore deposition. Probable sources of fluids are discussed. It is suggested that the factors controlling wolframite deposition could have been different even at the same deposit.  相似文献   
4.
Geology of Ore Deposits - A special investigation of fluid inclusions and geochemical and isotopic studies of their typomorphic features were carried out for danburite and datolite from skarn...  相似文献   
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Gypsum is an authigenic precipitate that forms under periods of accentuated aridity and occurs widely in arid zones. However its use in quantitative paleoclimatology has been limited due to the absence of a method to determine the timing of its formation. We present here the results of a feasibility study that demonstrates that the timing of the formation event of gypsum can be estimated using Electron Spin Resonance (ESR) analysis. We used well documented samples from White Sands in New Mexico, USA, the Thar Desert, India and lakes in the Simpson Desert and Mallee Region, Australia and found that ESR ages could be obtained using radiation sensitive SO4?, SO3? radicals and a photobleachable signal O3?. ESR signals were consistent with control ages based on contextual information. These suggest that the dating signals (SO4?, SO3?) are stable over time scales >100 ka. We propose that this stability of the SO4? signals over geological time scales arises due to hydrogen bonding between the water proton and the SO4? radical and that the suitability of these radiation-induced radicals comes from their being a part of the host matrix. Further, ESR along with Fourier Transform Infrared (FT-IR) Spectroscopy methods additionally inform on the geochemical pathways for gypsum formation and help elucidate complex formation processes even in samples that appeared unambiguous gypsum precipitates. Thus, the presence of Hannebachite (CaSO3.½H2O) and Mn2+ in Thar and Australian samples suggested a reducing environment such that low valence sulfur reacted with CaCO3 to form hannebachite and eventually gypsum. The presence of sulfur, partially as sulfite in Thar gypsum samples suggested that redox cycles were mediated by microbial activity. Absence of these features in White Sands samples suggested oxic conditions during gypsum precipitation.  相似文献   
6.
The present study aimed at characterizing the heavy metal resistance and assessing the resistance pattern to multiple heavy metals (300 mmol L?1) by Palk Bay sediment bacteria. From 46 isolates, 24 isolates showed resistance to more than eight heavy metals. Among the 24 isolates S8-06 (Bacillus arsenicus), S8-10 (Bacillus pumilus), S8-14 (B. arsenicus), S6-01 (Bacillus indicus), S6-04 (Bacillus clausii), SS-06 (Planococcus maritimus) and SS-08 (Staphylococcus pasteuri) exhibited high resistance against arsenic, mercury, cobalt, cadmium, lead and selenium. Plasmid curing confirmed that the heavy metal resistance in S8-10 is chromosomal borne. Upon treatment with the heavy metals, the strain S8-10 showed many morphological and physiological changes as shown by SEM, FTIR and AAS analysis. S8-10 removed 47% of cadmium and 96% of lead from the growth medium. The study suggests that sediment bacteria can be biological indicators of heavy metal contamination.  相似文献   
7.
Stochastic Environmental Research and Risk Assessment - The resurfacing of urban road networks is a prevalent practice for extending their life and therefore shares an important contribution to the...  相似文献   
8.
The crustal evolution of northwestern India is marked by several episodes of acid magmatism during Late Proterozoic period (900-700 Ma). These events occurred during the culmination of Delhi orogenic cycle and continued till the emergence of a stable Aravalli craton. Some of these granites emplaced within the Delhi Supergroup of rocks in central and southern parts of Rajasthan are associated with tungsten mineralisation. This includes three important tungsten deposits, namely those of Degana, Sirohi and Sewariya areas. The geological setting, petrography and geochemical characteristics of the mineralised granites in these deposits are comparable while these features are quite different in non-mineralised granites of this region.Comparison of mineralised granites in the three areas indicates that: (1) these are relatively small plutons, (2) they are emplaced at high crustal level, (3) the roof of the pluton is either just exposed or lies closely beneath ground surface, and (4) the granites are geochemically specialised with enrichment of alumina, W, B, F, Rb and Li, and depletion of Sr.  相似文献   
9.
Major geotectonic elements that are seismically active in the near-shore areas of the Indian subcontinent are the Mekran fault off the coast of Pakistan, the western part of the Narmada-Son lineament, the West Coast Fault off the west coast of India - a southward extension of the Cambay Rift, the Palghat Gap, the Godavari and Mahanadi grabens, transecting rather at an angle to the eastern coast of India and the Arakan-Yoma arcuate belt of Burma, which is a part of the global Alpine-Himalayan orogenic belt, continuing southwards into the Andaman-Nicobar island complex and the Java-Sumatra trench on the ocean floor of the advancing Indo-Australian Plate.The coastal belt exhibits varied degrees of seismicity from intensely seismic areas, like the Mekran coast off Pakistan, Kutch (India) and the Arakan-Yoma belt of Burma, with earthquake magnitudes of more than 8.0, while the intervening coastal areas of the Peninsular India are moderately seismic to aseismic. The remaining areas, namely, the major part of the coastal belt of Bay of Bengal in India and Bangladesh are broadly aseismic. However, the active Godavari graben and the eastern part of the coast of Bangladesh are frequented by low to moderate magnitude earthquakes. An extension of the active Arakan-Yoma belt in the Bay of Bengal in the form of the Andaman-Nicobar Island complex is highly seismic with a maximum earthquake magnitude of more than 8.0, while the Lakshadweep-Minicoy island complex, situated on the Chagos-Laccadive ridge is moderately seismic. This broad picture of coastal and marginal seismicity is corroborated by the geodynamics of the northern part of the Indo-Australian Plate.Observations along the coastal areas during historic and recent times, however, confirm the absence of significant tsunamis, though very mild tsunami surges have occasionally been observed along the coastal areas of the Bay of Bengal. No active volcanoes are known to exist in the coastal areas.Water reservoirs situated near the marginal areas of the Peninsular Shield exhibit moderate to intense seismic activities, viz. Ukai, Bhatsa, Koyna, Parambikulam, Sholayar, Idduki, and Kinnersani.  相似文献   
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