40Ar/39Ar geochronology and geochemistry of the Central Saurashtra mafic dyke swarm: insights into magmatic evolution,magma transport,and dyke-flow relationships in the northwestern Deccan Traps     

Ciro Cucciniello  Elena I. Demonterova  Hetu Sheth  Kanchan Pande  Anjali Vijayan 《Bulletin of Volcanology》2015,77(5):1-19

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40Ar/39Ar geochronology of subaerial lava flows of Barren Island volcano and the deep crust beneath the Andaman Island Arc,Burma Microplate     

Jyotiranjan S. Ray  Kanchan Pande  Rajneesh Bhutani 《Bulletin of Volcanology》2015,77(6):1-10

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Elaine Enarson and P.G. Dhar Chakrabarti (eds), Women,Gender and Disasters: Global Issues and Initiatives     

Kanchan Gandhi 《Singapore journal of tropical geography》2010,31(3):407-409

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Origin and geochemical characterization of the glauconites in the Upper Cretaceous Lameta Formation,Narmada Basin,central India     

Udita Bansal  Santanu Banerjee  Dhiren K.Ruidas  Kanchan Pande 《古地理学报》2018,(2)

This study presents geochemical characteristics of glauconites in estuarine deposits within the Maastrichtian Lameta Formation in central India. Resting conformably over the Bagh Group, the Lameta Formation consists of ~4-5 m thick arenaceous, argillaceous and calcareous green sandstones underlying the Deccan Traps. The sandstone is friable, medium-to coarse-grained, well-sorted and thoroughly crossstratified, and contains marine fossils. Detailed petrography, spectroscopy and mineral chemistry indicates unique chemical composition of glauconite with high K_2O, MgO, Al_2O_3 and moderate TFe_2O_3. Glauconite is formed by the replacement of K-feldspars, initially as stringers in the cleavages and fractures of feldspars. Incipient glauconite subsequently evolves fully, appearing as pellets. Fully-evolved glauconite pellets often leave tiny relics of K-feldspar. XRD exhibits characteristic peak of 10A from basal(001)reflection of glauconite, indicating the "evolved" character. The K_2O content of glauconites in the Lameta Formation varies from 5.51% to 8.29%, corroborating the "evolved" to "highly-evolved" maturation stage.The TFe_2O_3 content of glauconite varies from 12.56% to 18.90%. The PASS-normalized-REE patterns of glauconite exhibit a "hat-shape" confirming the authigenic origin of glauconites. The slightly-negative to slightly-positive Ce anomaly value and the moderate TFe_2O_3 content of glauconite agree well with a suboxic,estuarine condition. The replacement of K-feldspar by the glauconite contributes towards the high K_2O content. Compositional evolution of glauconites in the Lameta Formation is similar to those observed in many Precambrian sedimentary sequences.  相似文献   

Indian national remote sensing award     

L. M. Pande 《Journal of the Indian Society of Remote Sensing》1999,27(1):i-ii

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Rainfall variability and indices of extreme rainfall-analysis and perception study for two stations over Central Himalaya,India   总被引：1，自引：1，他引：0  

Sneh Joshi  Kireet Kumar  Varun Joshi  Bimal Pande 《Natural Hazards》2014,72(2):361-374

The analysis of rainfall pattern and indices of extreme rainfall events is performed for two meteorological stations located in the Central Himalayan Region which is highly vulnerable to rain-induced hazards. The records of these rain-induced disasters suggest that such events are generally observed in later part of monsoon season, when soil is saturated after monsoon rains. An attempt is made here to test trends of 19 different extreme rainfall indices that have been widely used in the literature, using daily rainfall data for two urban centres (Nainital and Almora) over the period 1992–2005. We have used statistical tools such as Sen’s method and Mann–Kendall test for detection of trend in annual rainfall, monsoon rainfall, number of rainy days and 1-day extreme rainfall. Principal component analysis gives the correlation between different extreme rainfall indices. Time series of principal components are representing the trends of extreme indices, their variation and interrelation between different indices. The perception study conducted in the same sites indicates that extreme rainfall events and change in rainfall amount and timing are well perceived by the local people.  相似文献   

On the infrared opacity of sunspots     

G. C. Joshi  L. M. Punetha  M. C. Pande 《Solar physics》1979,64(2):255-259

In the umbral atmosphere the depth dependence of the opacity due to the vibration rotation bands of various abundant molecules in the wavelength region 1 m to 10 m has been calculated. In the higher layers of the umbral atmosphere, the molecular opacity seems to dominate the opacity due to the negative hydrogen ion.  相似文献   

The influence of a mature cyclonic eddy on particle export in the lee of Hawaii     

Kanchan Maiti  Claudia R. Benitez-Nelson  Yoshimi Rii  Robert Bidigare 《Deep Sea Research Part II: Topical Studies in Oceanography》2008,55(10-13):1445

Mesoscale eddies may enhance primary production (PP) in the open ocean by bringing nutrient-rich deep waters into the euphotic zone, potentially leading to increased transport of particles to depth. This hypothesis remains controversial, however, due to a paucity of direct particle export measurements. In this study, we investigated particle dynamics using ²³⁴Th–²³⁸U disequilibria within a mesoscale cold-core eddy, Cyclone Opal, which formed in the lee of the Hawaiian Islands. ²³⁴Th samples were collected along two transects across Cyclone Opal as well as during a time-series within the eddy core during a decaying diatom bloom. Particulate carbon (PC), particulate nitrogen (PN) and biogenic silica (bSiO₂) fluxes at 150 m varied spatially and temporally within the eddy and strongly depended on the ²³⁴Th model formulation used (e.g., steady state versus non-steady state, inclusion of upwelling, etc.). Particle fluxes estimated from a steady state model assuming an upwelling rate of 2 m day⁻¹ yielded the best fit to sediment-trap data. These ²³⁴Th-derived particle fluxes ranged from 332±14 to 1719±53 μmol C m⁻² day⁻¹, 27±3 to 114±12 μmol N m⁻² day⁻¹, and 33±20 to 309±73 μmol Si m⁻² day⁻¹. Although PP rates within Cyclone Opal were elevated by a factor of 2–3, PC and PN fluxes were the same, within error, inside and outside of Cyclone Opal. The ratio of PC export to PP remained surprisingly low at <0.03 and similar to those measured in surrounding waters. In contrast, bSiO₂ fluxes within the eddy core were three times higher. Detailed analyses of ²³⁴Th depth profiles consistently showed excess ²³⁴Th at 100–175 m, associated with the remineralization and possible accumulation of suspended and dissolved organic matter from the surface. We suggest that strong microzooplankton grazing facilitated particulate organic matter recycling and resulted in the export of empty diatom frustules. Thus, while eddies may increase PP, they do not necessarily increase PC and PN export to deep waters. This may be a general characteristic of wind-driven cyclonic eddies of the North Pacific Subtropical Gyre and suggests that eddies may preferentially act as a silica pump, thereby playing an important role in promoting silicic-acid limitation in the region.  相似文献   

The rotational motion in quiescent prominences     

M. C. Pande  K. R. Bondal 《Earth, Moon, and Planets》1991,54(2):119-124

On the basis of Kippenhahn and Schlüter's magnetohydrostatic model of a quiescent prominence we have attempted to study the effect of a rotational velocity field in it. We find that a physically plausible solution is not possible in the vertical plane. A possibility, however, is shown in the horizontal plane, with certain assumptions to get equal velocity contours.  相似文献   

The nature of velocity fields in quiescent prominences     

K. R. Bondal  M. C. Pande 《Astrophysics and Space Science》1991,181(1):161-163

It is shown that for certain definite conditions of symmetry imposed on the permitting magnetic field geometry for an isothermal case in Kippenhahn and Schlüter's (1957) model of a quiescent prominence, any irrotational velocity field would quickly get converted to rotational.  相似文献