Glauconites from the Late Palaeocene — Early Eocene Naredi Formation,western Kutch and their genetic implications     

Shovan Lal Chattoraj  Santanu Banerjee  P. K. Saraswati 《Journal of the Geological Society of India》2009,73(4):567-574

Glauconitic minerals are considered as one of the valuable input parameters in sequence stratigraphic analysis of a basin. In the present study glauconitic minerals are reported from subtidal green shale facies in the lower part of the Late Paleocene-Early Eocene Naredi Formation of western Kutch. On the basis of the foraminiferal assemblage the glauconite bearing beds are interpreted to have formed in a mid shelf depositional settings of an unstable marine conditions. XRD studies confirm the glauconite mineralogy of the green pellets and provide an estimation of glauconite maturity. Textural attributes of the glauconites confirm their derivation by different degrees of alteration of precursor feldspar grains. Because of the authigenic origin and autochthonous nature, these glauconites hold promise for understanding sequence stratigraphy of the Palaeogene succession of the western Kutch.  相似文献   

Bianchi type VI0 magnetized bulk viscous massive string cosmological model in General Relativity     

Raj Bali  Ratna Banerjee  S. K. Banerjee 《Astrophysics and Space Science》2008,317(1-2):21-26

The paper consists of some exact solutions for a homogeneous Bianchi type VI₀ universe. The material distribution is taken to be a magnetized bulk viscous fluid in presence of massive cosmological string. We assume that current is flowing along x-direction. Therefore, the magnetic field is in yz-plane. For deterministic model of the universe, we assume that shear (σ) is proportional to the expansion (θ) and ζ θ=constant=ξ where ζ the coefficient of bulk viscosity and θ the expansion in the model. The physical and kinematical parameters of the models thus formed are discussed.  相似文献   

Effect of Surface Heterogeneity on the Boundary-Layer Height: A Case Study at a Semi-Arid Forest     

Peter Brugger  Tirtha Banerjee  Frederik De Roo  Konstantin Kröniger  Rafat Qubaja  Shani Rohatyn  Eyal Rotenberg  Feodor Tatarinov  Dan Yakir  Fulin Yang  Matthias Mauder 《Boundary-Layer Meteorology》2018,169(2):233-250

We investigate the effects of an isolated meso-\(\gamma \)-scale surface heterogeneity for roughness and albedo on the atmospheric boundary-layer (ABL) height, with a case study at a semi-arid forest surrounded by sparse shrubland (forest area: \(28~\text{ km }^2\), forest length in the main wind direction: 7 km). Doppler lidar and ceilometer measurements at this semi-arid forest show an increase in the ABL height over the forest compared with the shrubland on four out of eight days. The differences in the ABL height between shrubland and forest are explained for all days with a model that assumes a linear growth of the internal boundary layer of the forest through the convective ABL upwind of the forest followed by a square-root growth into the stable free atmosphere. For the environmental conditions that existed during our measurements, the increase in ABL height due to large sensible heat fluxes from the forest (\(600~\text {W~m}^{-2}\) in summer) is subdued by stable stratification in the free atmosphere above the ABL, or reduced by high wind speeds in the mixed layer.  相似文献   

Photonic dating of prehistoric irrigation canals at Phoenix,Arizona, U.S.A.*     

Glenn W. Berger  T. Kathleen Henderson  D. Banerjee  Fred L. Nials 《Geoarchaeology》2004,19(1):1-19

A number of archeological features, including in‐filled irrigation canals of uncertain prehistoric age, occur within the Holocene floodplain of the Salt River at Phoenix, Arizona. In the first attempt to date irrigation‐canal sediments using luminescence methods, we obtained age estimates of 1640 ± 190 yr B.P. (1σ) (multi‐aliquot or MA) and 1621 ± 95 yr B.P. (post‐IR single‐aliquot‐regenerative‐dose or SAR) for a single sample from the base of the oldest canal‐infilling deposits (all IR‐PSL ages reported in this article are in calendar years before A.D. 2001). For the remaining canal samples, weighted mean luminescence ages of 819 ± 45 yr (MA) and 826 ± 32 yr (post‐IR SAR) were obtained. Thus from photonic dating we can resolve the first and last phases of canal use at this Phoenix site: initiation at ca. 1600 years ago and final use at ca. 800 years ago. These results demonstrate the power of SAR luminescence sediment dating to enhance our understanding of prehistoric irrigation‐canal development and usage here and elsewhere in the world. © 2004 Wiley Periodicals, Inc.  相似文献   

Solving archaeological problems using techniques of soil magnetism     

Rinita A. Dalan  Subir K. Banerjee 《Geoarchaeology》1998,13(1):3-36

Archaeological investigations into the processes and factors controlling the magnetic enhancement of soils were initiated in the 1960s in conjunction with the application of magnetic prospection surveys. After a highly productive period of research, archaeological interest in soil magnetism experienced a downswing, which has just recently been reversed. Continuing research within the fields of rock magnetism and environmental magnetism has refined our understanding of the processes and products of magnetic enhancement and demonstrated the broad applicability of soil magnetic analyses. Using this information, together with recent archaeological studies, we update archaeologists on the variety of soil magnetic techniques and how they can be utilized to define, detail, and understand archaeological sites, features, and environments. A case study at the Cahokia Mounds Site in southwestern Illinois illustrates how soil magnetic techniques can be interfaced with other methods to understand archaeological landscapes and landscape change. © 1998 John Wiley & Sons, Inc.  相似文献   

Estimation of Arsenic Toxicity by Analysis of Certain Marker Enzymes of the Air‐Breathing Catfish Clarias batrachus (Linn.)          下载免费PDF全文

Randhir Kumar  Tarun Kumar Banerjee 《洁净——土壤、空气、水》2014,42(5):690-695

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Forecasting of groundwater level in hard rock region using artificial neural network   总被引：2，自引：0，他引：2  

Pallavi Banerjee  R. K. Prasad  V. S. Singh 《Environmental Geology》2009,58(6):1239-1246

In hardrock terrain where seasonal streams are not perennial source of freshwater, increase in ground water exploitation has already resulted here in declining ground water levels and deteriorating its’ quality. The aquifer system has shown signs of depletion and quality contamination. Thus, to secure water for the future, water resource estimation and management has urgently become the need of the hour. In order to manage groundwater resources, it is vital to have a tool to predict the aquifer response for a given stress (abstraction and recharge). Artificial neural network (ANN) has surfaced as a proven and potential methodology to forecast the groundwater levels. In this paper, Feed-Forward Network based ANN model is used as a method to predict the groundwater levels. The models are trained with the inputs collected from field and then used as prediction tool for various scenarios of stress on aquifer. Such predictions help in developing better strategies for sustainable development of groundwater resources.  相似文献   

Substrate control on formation and maturation of glauconites in the Middle Eocene Harudi Formation, western Kutch, India     

Santanu Banerjee  Shovan Lal ChattorajP.K. Saraswati  Somnath DasguptaUrbashi Sarkar 《Marine and Petroleum Geology》2012,30(1):144-160

Formation and maturation of glauconites within the early Middle Eocene Harudi Formation, built up in a lagoon to shelf transition in western Kutch, India is addressed taking recourse to a combined sedimentological, micropalaeontological and mineralogical investigation. The glauconite is authigenic and its occurrence coincides with maximum flooding. The glauconite is more matured within the fecal pellets and is less matured within the intra-particle pores of bioclasts namely, foraminifera, ostracoda, gastropoda and bryozoa. SEM-EDS, XRD and geochemical studies clearly document that the infilling within the intra-particle pores of bioclasts belong to nascent to slightly evolved glauconite (<5 wt% K₂O), while the pellet belongs to slightly evolved to evolved glauconite (5-7 wt% K₂O). Based on chemical characteristics and SEM investigations the glauconitization process can be best explained by the ‘verdissement theory’. The glauconite possibly formed as initial authigenic glauconitic smectite precipitates; while the pellet matured subsequently by addition of K, the process was hindered in case of infillings. The maturation process also involved addition of Si and release of Al, with or without release of Mg. The glauconite maturation was facilitated in case of fecal pellets because of higher porosity, inter-granular nature of pores and availability of necessary elements in semi-confined micro-environments. In contrast, the maturation was aborted at an early stage in case of infillings because of the minute, closed nature of the pores and prevalent alkaline conditions not allowing dissolution of calcitic tests. A low negative cerium anomaly suggests glauconite formation in sub-oxic micro-environments, created by decay of organic matters within the fecal pellets and bioclasts. A clear case of substratum control on glauconitization becomes apparent.  相似文献   

Application of an Alkali Functionalized Material for Treating Pharmaceutical Wastewater Containing Chlorhexidine Gluconate and Cetrimide          下载免费PDF全文

Debasree Banerjee  Shyamal Jana  Ujjaini Sarkar  Debasri Roy 《洁净——土壤、空气、水》2016,44(2):169-179

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Central Himalayan crystallines as the primary source for the sandstone–mudstone suites of the Siwalik Group: New geochemical evidence     

Nikesh Ranjan  D.M. Banerjee   《Gondwana Research》2009,16(3-4):687-696

Geochemistry of the Sub-Himalayan foreland basin Siwalik sediments has been used for interpreting the nature of the source rocks. This study has shown that the compositional changes are a function of stratigraphic height, demonstrated by the upward increase of P₂O₅, Na₂O, CaO, MgO and SiO₂ content from Lower to the Upper Siwalik rocks. On the other hand, K₂O, Fe₂O₃, TiO₂ and Al₂O₃ show decrease with the increasing stratigraphic height. These trends are a clear reflection of time-controlled changes in the source lithology. Ratios such as Eu/Eu*, (La/Lu)_cn, La/Sc, Th/Sc, La/Co, and Cr/Th suggest a prominent felsic source area for the Siwalik sediments. Chondrite-normalized REE pattern with LREE enrichment and moderately flat HREE pattern with sharp negative Eu anomaly are attributed to a felsic source. Contrary to the existing belief, this study has ruled out any contribution from the mafic sources and highlighted the compositional similarities of Siwalik sediments with the crustal proxies like PAAS, NASC and UCC. The geochemical data point to a significant role played by the Precambrian and early Paleozoic granitic rocks of the Himalayan tectogene in shaping the composition of the foreland sediments. The variable CIA values and marked depletion in Na, Mg and Ca exhibited by the Lower, Middle and Upper Siwalik sediments reflect variable climatic zones and variations in the rate of tectonic uplift of the source area. Our results demonstrate that in the Lower Siwalik and part of the Middle Siwalik, Higher Himalayan Crystalline sequence (HHCS) was the primary source area with minor contributions by the meta-sedimentary succession of the Lesser Himalaya. Later, during the deposition of the upper part of the Middle Siwalik and Upper Siwalik, the source terrain switched positions. These two prominent source terrains supplied sediments in steadily changing proportion through time.  相似文献