X-ray crystallography of uraninites associated with the albitite belt of western India: Evidence for the high-temperature origin of uranium and associated mineralisation     

Yamuna Singh  R. Viswanathan  P. S. Parihar  P. B. Maithani 《Journal of the Geological Society of India》2013,81(1):79-90

X-ray diffraction (XRD) studies on the radioactive ore samples from various parts of Rajasthan and Haryana have revealed the presence of several uranium and other atomic mineral occurrences in the albitite belt of western India. The primary uranium minerals (PUMs) are uraninite and brannerite, whereas, the secondary uranium minerals (SUMs) show considerable speciations: phosphate, silicate, hydrous oxide hydrate, and vanadate. Multiple oxides (MOs) are davidite, fergusonite, aeschynite-(Y), microlite, samarskite, euxenite, betafite, and columbite-tantalite. The thorium minerals are huttonite, thorite, uranoan-thorite, thorianite, thorutite, and brabantite. The yttrium and REE-bearing minerals are xenotime, britholite, allanite, chevkinite, tritomite, and monazite. It is noted that the measured unit cell dimension (a₀) of the investigated uraninites ranges from 5.4110 Å to 5.4646 Å. The highest unit cell dimension (5.4646 Å) represents a composition (or oxidation grade) of UO_2.05, whereas, the lowest one (5.4110 Å) corresponds to a composition of UO_2.54. Furthermore, it is also apparent that, with increase in oxidation grade, there is a concomitant decrease in unit cell dimension. As most of the values of a_o of uraninites from the albitite belt are high (> 5.45 Å), it may be inferred that the overall temperature of formation of uraninites of the albitite belt was higher (ca. 400°C). However, the low values of a₀ in certain localities could be due to the prevalence of relatively low and fluctuating temperature regimes locally (ca. 400°–100° C). Numerous occurrences of refractory, multiple oxides, and REE minerals, in association with uranium mineralisation, also support a high-temperature origin for the investigated uraninites. Binary data plots of unit cell dimension (a₀) versus oxidation grade/composition (UO_2+x) of uraninites (n = 36) suggest that the gross uranium mineralisation in the albitite belt of western India is mainly linked to regional metamorphism, anatexis, granitic intrusion, metasomatism, and contact metamorphosed granite-pegmatite aureoles and granite-related vein type with hydrothermal overprints, including redistribution of intrinsic sedimentary uranium and its concentration along suitable structural locales. These interpretations are consistent with the known gross geologic features of the albitite belt. Furthermore, the presence of marialite (calcian) in many places in the albitite belt also supports such a contention, as this mineral is known to be restricted to metamorphic and metasomatic environments. The speciation of secondary uranium minerals could be due to the higher oxidation of U⁴⁺ to U⁶⁺ in surface to near-surface conditions and its (U⁶⁺) remobilisation as uranyl ions. The combination of moving uranyl ions with available cations and anions en route caused re-precipitation of U as diversified assemblages of low-temperature uranyl minerals under suitable physicochemical conditions.  相似文献   

Fluid inclusion study of the Higher Himalayan quartzitic pelites, Garhwal Himalaya, India: Implications for recrystallization history of metasediments     

Himanshu K. Sachan  Anubhooti Saxena  Preeti Verma  Santosh K. Rai  Aditya Kharya 《Journal of the Geological Society of India》2013,82(5):509-518

Quartzitic pelites forms a part of Higher Himalayan Crystalline of higher geotectonic zone in Garhwal Himalaya. Quartzitic pelites (locally known as Pandukeshwar Quartzite) in Garhwal Himalaya is sandwiched between high grade metamorphic rocks of Central Crystallines and Badrinath Formation. Fluid inclusion studies are carried out on the detrital, and recrystallized quartz grains of quartzitic pelites to know about the fluid phases present during recrystallization processes at the time of maximum depth of burial. The quartzitic pelite (Pandukeshwar Quartzite) essentially consists of recrystallised quartz with accessory minerals like mica and feldspar. Fluid microthermometry study reveals the presence of three types of fluids: (i) high-salinity brine, (ii) CO₂-H₂O and (iii) H₂O-NaCl. These fluids were trapped during the development of grain and recrystallization processes. The high saline brine inclusions and CO₂-H₂O fluid with the density of 0.90 to 0.97 gm/cm³ are remnants of provenance area. CO₂ density in detrital quartz grains characterise the protolith of the sandstone as granite or metamorphic rock. The H₂O-NaCl fluids involved in the recrystallization processes at temperature-pressure of 430-350°C; 4.8 to 0.5 Kbars as constrained by fluid isochores of CO₂-H₂O and H₂O-NaCl inclusions and bulging and subgrain development during recrystallization processes. The re-equilibration of the primary fluid due to elevated internal and confining pressure is evident from features like ‘C’ shaped cavities, stretching of the inclusions, their migration and decrepitation clusters. The observed inclusion morphology revealed that the rocks were exhumed along an isothermal decompression path.  相似文献   

Interpretation of aero-magnetic data and satellite imagery to delineate structure — a case study for uranium exploration from Gwalior Basin,India     

A. Markandeyulu  I. Patra  B. V. S. N. Raju  A. K. Chaturvedi  P. S. Parihar 《Journal of the Geological Society of India》2012,80(3):382-392

The Paleo-Meso Proterozoic Gwalior basin (E - W), lying to NW fringe of Bundelkhand massif is represented by litho-package of lower arenaceous Par Formation and upper chemogenic Morar Formation. It is bounded by Indo-Gangetic alluvium in north and east, Kaimur sediments in west and Bundelkhand granitoids in south. Gwalior Basin has been the exploration target for uranium mineralization right from early 60’s. Surface radioactivity anomalies due to uranium has been reported in both Par and Morar Formations of Gwalior Group and Vindhyan sediments. Besides presence of syngenetic uranium in the system, presence of post-depositional faults and fractures are the favorable factors. Aeromagnetic survey was carried out by AMD in 2002 with N-S lines of 500 m interval covering 9406 line km. The data with sampling interval of 0.1 sec was corrected for spikes, diurnal variation, IGRF, heading and lag. Final processed images are prepared after suitable leveling and gridding. First vertical derivative of TMI-RTP and tilt-angle derivative images are used to map the litho-contacts, lineaments and structural features. Numerous NE-SW trending low amplitude and NW-SE trending high amplitude magnetic linears corroborate with quartz reefs and basic dykes respectively. Besides, E-W to WNW-ESE and ENE-WSW trending fractures are also evident from the processed image maps. Further, the Euler’s depth solution of gridded aeromagnetic data calculated for structural indices of 0 and 1 are very consistent in locating the position of the causative sources. Based on the amplitude and textural character of processed aeromagnetic data, alteration zone is delineated well within the Morar Formation. Enhanced Thematic Mapper (ETM+) image with 30m resolution was merged with IRS PAN 1D (5.8 m resolution) for better spatial/radiometric resolution to extract litho-contacts and lineament patterns. Merged PAN band-4 after linear contrast and edge enhancement techniques deciphered detailed lineament pattern, which corroborate the magnetic data. Merged ETM+ (RGB 751) and PC (PC1-PC2-PC5) images depict litho-logical contrast. Integration of aeromagnetic and satellite imagery data helped in understanding the structural fabric of the Gwalior Basin and to identify favorable loci of uranium mineralization.  相似文献   

Analysis of Observational Characteristic Features of the Eulerian Autocorrelation Function in Low and Moderate Wind Conditions     

Dhuria  Aditya Kumar  Sharan  Maithili 《Boundary-Layer Meteorology》2022,184(3):531-549

Boundary-Layer Meteorology - Turbulent data from three sites are utilized to analyze the characteristic features of the Eulerian autocorrelation function (EAF) of horizontal (longitudinal and...  相似文献   

Use of SWAT to determine the effects of climate and land use changes on streamflow and sediment concentration in the Purna River basin,India   总被引：1，自引：0，他引：1  

Aditya P. Nilawar  Milind L. Waikar 《Environmental Earth Sciences》2018,77(23):783

A semi-distributed, physically based, basin-scale Soil and Water Assessment Tool (SWAT) model was developed to determine the key factors that influence streamflow and sediment concentration in Purna river basin in India and to determine the potential impacts of future climate and land use changes on these factors. A SWAT domain with a Geographical Information System (GIS) was utilized for simulating and determining monthly streamflow and sediment concentration for the period 1980–2005 with a calibration period of 1980–1994 and validation period of 1995 to 2005. Additionally, a sequential uncertainty fitting (SUFI-2) method within SWAT-CUP was used for calibration and validation purpose. The overall performance of the SWAT model was assessed using the coefficient of determination (R²) and Nash–Sutcliffe efficiency parameter (E_NS) for both calibration and validation. For the calibration period, the R² and E_NS values were determined to be 0.91 and 0.91, respectively. For the validation period, the R² and E_NS were determined to be 0.83 and 0.82, respectively. The model performed equally well with observed sediment data in the basin, with the R² and E_NS determined to be 0.80 and 0.75 for the calibration period and 0.75 and 0.65 for the validation, respectively. The projected precipitation and temperature show an increasing trend compared to the baseline condition. The study indicates that SWAT is capable of simulating long-term hydrological processes in the Purna river basin.  相似文献   

Subsurface profiling of granite pluton using microtremor method: southern Aravalli,Gujarat, India     

Joshi  Aditya U.  Sant  Dhananjay A.  Parvez  Imtiyaz A.  Rangarajan  Govindan  Limaye  Manoj A.  Mukherjee  Soumyajit  Charola  Mitesh J.  Bhatt  Meghnath N.  Mistry  Sagar P. 《International Journal of Earth Sciences》2018,107(1):191-201

International Journal of Earth Sciences - We report, using the microtremor method, a subsurface granitic pluton underneath the Narukot Dome and in its western extension along a WNW profile, in...  相似文献   

Post-outburst phase of McNeil's nebula (V1647 Orionis)     

D. K. Ojha  S. K. Ghosh  A. Tej  R. P. Verma  S. Vig  G. C. Anupama  D. K. Sahu  P. Parihar  B. C. Bhatt  T. P. Prabhu  G. Maheswar  H. C. Bhatt  B. G. Anandarao  V. Venkataraman 《Monthly notices of the Royal Astronomical Society》2006,368(2):825-836

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Characterization of agroecosystem based on land utilization indices using remote sensing and GIS     

Indrani Choudhury  M. Chakraborty  S. C. Santra  J. S. Parihar 《Journal of the Indian Society of Remote Sensing》2006,34(1):23-37

Information on various agricultural resource parameters at various levels is essential for proper management and efficient resource allocation for sustainable agricultural development. Limitations in ground-based method have encouraged the use of satellite data coupled with geographical information system (GIS) in providing spatial as well as temporal information over large and inaccessible areas. In the present study, an attempt has been made to generate raster maps using remote sensing and GIS techniques to characterize the agroecosystem of South 24 Paraganas district of West Bengal, based on land utilization indices. Information on multi-season landcover derived from the analysis of the multi-temporal RADARSAT-1 SAR and IRS-ID LISS III data as well as other ancillary information in GIS environment are the basic inputs used in the study. The present analysis shows that northern and northwestern parts are more diverse in terms of agricultural intensification as compared to the southern and northeastern parts whereas the central parts show moderate density. In terms of carrying capacity, the high carrying capacity has been observed in the southern to northeastern parts whereas the northwestern and central parts show moderate and northern parts show low carrying capacity. Overall, the characterization of agroecosystem using land utilization indices can be identified as major input to formulate a management plan for sustainable agriculture with concerns for the environment.  相似文献   

Multiple forecasts of kharif rice in orissa state-four year experience of fasal pilot study     

N. K. Patel  M. Chakraborty  S. Dutta  C. Patnaik  J. S. Parihar  S. C. Moharana  A. Das  B. K. Sarangi  G. Behera 《Journal of the Indian Society of Remote Sensing》2004,32(2):125-143

Considering the requirement of multiple pre-harvest crop forecasts, the concept of Forecasting Agricultural output using Space, Agrometeorology and Land based observations (FASAL) has been formulated. Development of procedure and demonstration of this technique for four in-season forecasts for kharif rice has been carried out as a pilot study in Orissa State since 1998. As the availability of cloud-free optical remote sensing data during kharif season is very poor for Orissa state, multi-date RADARSAT SCANSAR data were used for acreage estimation of kharif rice. Meteorological models have been developed for early assessment of acreage and prediction of yield at mid and late crop growth season. Four in-season forecasts were made during four kharif seasons (1998-2001); the first forecast of zone level rice acreage at the beginning of kharif crop season using meteorological models, second forecast of district level acreage at mid growth season using two-date RADARSAT SCANSAR data and yield using meteorological models, third forecast at late growth season of district level acreage using three-date RADARSAT SCANSAR data and yield using meteorological models and revised forecast incorporating field observations at maturity. The results of multiple forecasts have shown rice acreage estimation and yield prediction with deviation up to 14 and 11 per cent respectively. This study has demonstrated the potential of FASAL concept to provide inseason multiple forecasts using data of remote sensing, meteorology and land based observations.  相似文献   

Wheat acreage estimation for Haryana using satellite digital data     

V. K. Dadhwal  D. S. Ruhal  T. T. Medhavy  S. D. Jarwal  A. P. Khera  J. Singh  Tara Sharma  J. S. Parihar 《Journal of the Indian Society of Remote Sensing》1991,19(1):1-15

This paper summarizes the procedures adopted and results obtained since 1985–86 for wheat inventory for Haryana using satellite digital data (MSS: 1985–86 to 1987–88, LISS-I: 1988–89 onwards). The approach followed is based on sample segments (10 × 10 km during 1985–86 to 1988–89, 7.5 × 7.5 km during 1989–90) and 10 percent sampling fraction and stratified sample design. There has been consistent improvement in accuracy over the years as judged from lower biases when compared with Bureau of Economics and Statistics (BES) acreage estimates and higher precision. In 1989–90, the state-level estimate achieved an accuracy goal of 90 percent at 90 percent confidence interval. A number of studies which have been carried out to study effect of choice of sensor, acquisition date, stratification approach, classification procedure on wheat inventory are also mentioned.  相似文献