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Petrological and geochemical characteristics of the granites from the Khanak and Devsar areas have been discussed in this paper. Based on field, petrographical and geochemical observations, three types of granites (grey, green and pink granite) have been identified in these areas. Grey granites consist of quartz, plagioclase, biotite, hornblende as essential minerals and hematite, zircon, annite, monazite & rutile as accessory minerals. Petrographically, green granites are same as grey granites including perthite and zircon as accessory minerals. Pink granites consist of quartz, k-feldspar and biotite in Khanak whereas in Devsar granites alike as Khanak granites, but plagioclase is replaced by perthite and occurs as dominantly. Microscopically, granites of both areas show porphyritic, hypidiomorphic, granophyric, perthitic and micro granophyric textures. Geochemically, major oxide elements (except alkalies) and trace elements (Ba, Sr, Cr, Ni, V, Cu, Zn, Ga, Pb, Th and Zr) are more in green and grey granites of Khanak and Devsar areas than pink granites. Generally, they show enrichments in SiO2, Na2O+K2O, Fe/Mg, Rb, Zr, Y and and AI (Agpaitic Index) (ranges from 0.10 to 1.18) and depletion in MgO, CaO, P, Ti, Ni, Cr and V indicate their A-type affinity which is very similar to the A-type granites of MIS (Malani igneous suite) in northwestern peninsular India. Green and grey granites of Devsar area show high concentrations of Heat production (HP) 9.68 & 11.70 μWm-3 and total Heat Generation Unit (HGU) i.e 23.04 & 27.86 respectively. On the other hand, pink granites of Khanak area display a higher enrichment of HP (16.53 μWm-3) and HGU (39.37) than those granites of Devsar area. Overall, they have much a higher values of HP and HGU than the average value of continental crust (3.8 HGU), which imply a possible linear relationship with the surface heat flow and crustal heat generation in the rocks of MIS. From the petrography as well as the chemistry of Khanak and Devsar granites, it is suggested that they might have derived from the different degree of partial melting from the similar source of magma. 相似文献
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M. C. Ramadevi S. Seetha Dipankar Bhattacharya B. T. Ravishankar N. Sitaramamurthy G. Meena M. Ramakrishna Sharma Ravi Kulkarni V. Chandra Babu Kumar Brajpal Singh Anand Jain Reena Yadav S. Vaishali B. N. Ashoka Anil Agarwal K. Balaji G. Nagesh Manoj Kumar Dhruti Ranjan Gaan Prashanth Kulshresta Pankaj Agarwal Mathew Sebastian A. Rajarajan D. Radhika Anuj Nandi V. Girish Vivek Kumar Agarwal Ankur Kushwaha Nirmal Kumar Iyer 《Experimental Astronomy》2017,44(1):11-23
Scanning Sky Monitor (SSM) onboard AstroSat is an Xray sky monitor in the soft X-ray band designed with a large field of view to detect and locate transient X-ray sources and alert the astronomical community about interesting phenomena in the X-ray sky. SSM comprises position sensitive proportional counters with 1D coded mask for imaging. There are three detector units mounted on a platform capable of rotation which helps covering about 50% of the sky in one full rotation. This paper discusses the elaborate details of the instrument and few immediate results from the instrument after launch. 相似文献
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D. Bala Subrahamanyam Radhika Ramachandran S. Indira Rani P. K. Kunhikrishnan B. Prasad Kumar 《Boundary-Layer Meteorology》2008,127(2):333-344
Surface-layer meteorological observations obtained from oceanic buoys over the Korean Strait and the Yellow Sea are used to
estimate surface-layer turbulent fluxes of heat, moisture and momentum over the East-Asian Marginal Seas. Special emphasis
is paid towards explanation of the impact of the Tsushima warm current flowing through the Korean Strait on air–sea interface
fluxes. During the active phase of the Tsushima warm current, when the difference in sea surface temperature and air temperature
becomes as large as 8°C, the sensible heat flux increases to a value of about 135 W m−2, while the latent heat flux is around 200 W m−2. The study attempts to broaden our understanding on the air-sea interaction processes over the Yellow Sea and Korean Strait. 相似文献
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Denny P. Alappattu D. Bala Subrahamanyam P. K. Kunhikrishnan Radhika Ramachandran K. M. Somayaji R. Venkatesh G. S. Bhat A. Bhagavath Singh 《Boundary-Layer Meteorology》2008,126(2):297-309
We report the spatio-temporal variability of surface-layer turbulent fluxes of heat, moisture and momentum over the Bay of
Bengal (BoB) and the Arabian Sea (AS) during the Integrated Campaign for Aerosols, gases Radiation Budget (ICARB) field experiment.
The meteorological component of ICARB conducted during March – May 2006 onboard the oceanic research vessel Sagar Kanya forms
the database for the present study. The bulk transfer coefficients and the surface-layer fluxes are estimated using a modified
bulk aerodynamic method, and then the spatio-temporal variability of these air-sea interface fluxes is discussed in detail.
It is observed that the sensible and latent heat fluxes over the AS are marginally higher than those over the BoB, which we
attribute to differences in the prevailing meteorological conditions over the two oceanic regions. The values of the wind
stress, sensible and latent heat fluxes are compared with those obtained for the Indian Ocean Experiment (INDOEX) period.
The variation of drag coefficient (C
D
), exchange coefficients of sensible heat and moisture (C
H
= C
E
) and neutral drag coefficient (C
DN
) with wind speed is also discussed.
相似文献
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Geotectonics - The present study is carried out to probe geodynamic evolution and tectonic history of A-type granitoids from the Riwasa and Nigana areas in the Tusham Ring Complex (TRC), western... 相似文献
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Radhika?Patro S.?N.?Mahapatro A.?BhattacharyaEmail author N.?C.?Pant J.?K.?Nanda A.?Dey A.?K.?Tripathy 《Contributions to Mineralogy and Petrology》2011,161(4):547-563
The origin of chemical and mineralogical heterogeneity in tens-of-microns wide layers and domains in enderbite-hosted couple-of-centimeters
wide pseudotachylite vein is examined based on the results of BSE and X-ray element imaging, and electron probe microanalyses
of major elements of host-rock minerals, clasts, microphenocrysts, and pseudotachylite matrix. The pseudotachylite layers
and domains containing variable proportions of orthopyroxene and magnetite microphenocrysts continue as mantles around quartz,
K-feldspar, plagioclase and garnet clasts. The clasts are chemically modified along margins and intra-clast pseudotachylite
injections. The chemical modifications are extensive in smaller clasts <5 μm diameter. At least three chemically distinct
layers and domains in the pseudotachylite, and their fine-grained matrices, plot in sharply defined, well-segregated and non-overlapping
fields in FeO + MgO−Al2O3–SiO2, FeO–CaO–MgO and CaO–Na2O–K2O and FeO vs. FeO/FeO + MgO diagrams. The compositions of the layers and domains—smeared between a feldspar + quartz component
and a ferromagnesian component of garnet + Fe–Ti oxides (±orthopyroxene)—possibly correspond to fractionated quenched melts,
or admixtures of microphenocrysts that cannot be resolved by the microbeam techniques employed. The compositional variations
are incompatible with deformation-driven crystal fractionation in melt. Instead the layers and domains possibly are crystal-melt
mushes produced by syn-deformation ultra-high temperature (1,250–1,375°C) melting reactions involving variable proportions
of host-rock minerals determined by time-transient local phase aggregates experiencing strain. The similar element variation
trends in pseudotachylite examined here and those reported from anorthosite, metapelite and charnockite elsewhere suggests
local phase aggregate controlled multi-reaction melting is a phenomenon commoner than hitherto realized in pseudotachylites. 相似文献
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Studies of eclipsing binaries with Hipparcos parallaxes are found to define a radiative flux relation for main sequence stars
in the spectral range from B6 – F0which is about as well as to the stars derived from angular diameters. At lower temperatures
the fluxes of the components fall below this curve which is caused due to the large intrinsic variations and starspots. From
the present analysis it is found that the secondary component of UV Piscium, a late type eclipsing binary, is a normal K3V
star and it fits the radiative flux-colour relation quite satisfactorily. This is explained due to the reliable values of
the fluxes and colours derived from the clean light curves (light curves obtained after removing the effect of the distortion
wave). However, the primary component which is also responsible for the intrinsic variations and starspots continue to deviate
from this curve.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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