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Dilip K Mukhopadhyay Bidyut K Bhadra Tamal K Ghosh Deepak C Srivastava 《Journal of Earth System Science》1996,105(2):157-171
Numerous peraluminous and porphyritic granitic bodies and augen gneisses of granitic compositions occur in the nappe sequences
of the Lower Himalaya. They are Proterozoic-to-lower Paleozoic in age and have been grouped into the ‘Lesser Himalaya granite
belt’. The mode of emplacement and tectonic significance of these granites are as yet uncertain but they are generally considered
to be sheet-like intrusions into the surrounding rocks. The small and isolated granite body (the Chur granite) that crops
out around the Chur peak in the Himachal Himalaya is one of the more famous of these granites. Several lines of evidence have
been adduced to show that the Chur granite has a thrust (the Chur thrust) contact with the underlying metasedimentary sequence
(locally called the Jutogh Group). The Chur granite with restricted occurrence at the highest topographic and structural levels
represents an erosional remnant of a much larger sub-horizontal thrust sheet. The contact relations between the country rocks
and many of the other granite and granitic augen gneisses in the Lesser Himalaya belt are apparently similar to that of the
Chur granite suggesting that at least some of them may also represent thrust sheets. 相似文献
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Basak Tanulku 《Geoforum》2012,43(3):518-528
The growing research on gated communities has largely regarded them as isolated and isolating places, rather than considering residents’ relations with other spaces and communities. This paper seeks to examine these external contacts through exploring the ways in which gated communities establish relations with local political actors. This is done through an examination of two gated communities in Gokturk and Omerli, Istanbul, and an analysis of the differences between them. On the basis of semi-structured in-depth interviews with residents and locals, the paper demonstrates how gated communities engage with the outside world in contrasting ways. By focusing on the conflict between Islamist and secular people, the paper also argues that gated communities are active urban agents, establishing interdependent relations with local political actors which can change urban space and politics. 相似文献
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The potassium supplying capacity of the waste mica powder (WMP) was evaluated through chemical and biological means. Four different size fractions of the WMP were studied in laboratory by different chemical extractants. At the same time, experiment of the plant growth was conducted in pot using K-deficient soil. The K release from the WMP by different extractants followed an increasing trend with an increase in the fineness of the particles. The highest K release was recorded by boiling 1 M HNO3 (376.4–1726.4 mg kg?1) followed by 1 M ammonium acetate (33.5–226.5 mg kg?1), 0.01 M citric acid (31.6–158.3 mg kg?1) and water (12.0–112.0 mg kg?1) irrespective of the various size fractions. Significantly, higher cumulative K release from the WMP in successive extraction was recorded with 1 M boiling HNO3 that predicts its slow-release property. The K release by different extractants was correlated significantly and positively with the biomass yield and K uptake by plants. 1 M boiling HNO3 extractable K showed higher correlation values with the biomass yield and K uptake. Therefore, it suggests that the extractant might be a better indicator of K supplying capacity of the WMP. The plant intervention was able to extract 32.8% of total K from the WMP simultaneously improving the exchangeable and non-exchangeable K pool in soil. These above-mentioned results conclude that plants can get access to a significant amount of K from the WMP and it could be an effective source of K in highly weathered tropical soils under K deficiency.
相似文献5.
NARX neural network approach for the monthly prediction of groundwater levels in Sylhet Sadar,Bangladesh 
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下载免费PDF全文 Abdullah Al Jami Meher Uddin Himel Khairul Hasan Shilpy Rani Basak Ayesha Ferdous Mita 《地下水科学与工程》2020,8(2):118-126
Groundwater is important for managing the water supply in agricultural countries like Bangladesh. Therefore, the ability to predict the changes of groundwater level is necessary for jointly planning the uses of groundwater resources. In this study, a new nonlinear autoregressive with exogenous inputs(NARX) network has been applied to simulate monthly groundwater levels in a well of Sylhet Sadar at a local scale. The Levenberg-Marquardt(LM) and Bayesian Regularization(BR) algorithms were used to train the NARX network, and the results were compared to determine the best architecture for predicting monthly groundwater levels over time. The comparison between LM and BR showed that NARX-BR has advantages over predicting monthly levels based on the Mean Squared Error(MSE), coefficient of determination(R~2), and Nash-Sutcliffe coefficient of efficiency(NSE). The results show that BR is the most accurate method for predicting groundwater levels with an error of ± 0.35 m. This method is applied to the management of irrigation water source, which provides important information for the prediction of local groundwater fluctuation at local level during a short period. 相似文献
6.
T. V. Mishenina T. I. Gorbaneva N. Yu. Basak C. Soubiran V. V. Kovtyukh 《Astronomy Reports》2011,55(8):689-703
We have determined abundances of copper, zinc, sodium, and aluminum in the atmospheres of 172 F, G, and K dwarf stars (−1.0
< [Fe/H] < 0.3) belonging to the Galaxy’s thin and thick disks and to the Hercules moving group. Our observations were performed
with the ELODIE échelle spectrometer on the 1.93-m telescope of the Haute Provence Observatory, with a resolving power of
R = 42 000 and signal-to-noise ratio S/N > 100. The Na, Al, Cu, and Zn abundances were derived in an LTE approximation; the synthetic spectrum for the copper lines
was calculated taking into account super-fine structure of the lines. We analyzed the abundances of these elements as a function
of metallicity [Fe/H] for stars of the thin and thick disks of the Galaxy and the Hercules moving group. The Cu abundances
and their trends with metallicity are essentially the same in the three studied sub-structures. The mean Al and Zn abundances
for stars of the thin and thick disks differ significantly. 相似文献
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Petrography and mineralogy of four calc-alkaline granitoid plutons Agarpur, Sindurpur, Raghunathpur and Sarpahari located from west to east of northern Purulia of Chhotanagpur Gneissic Complex, eastern India, are investigated. The plutons, as a whole, are composed of varying proportions of Qtz–Pl–Kfs–Bt–Hbl±Px–Ttn–Mag–Ap–Zrn±Ep. The composition of biotite is consistent with those of calc-alkaline granitoids. Hornblende–plagioclase thermometry, aluminium-in-hornblende barometry and the assemblage sphene–magnetite–quartz were used to determine the P, T and \(f_{\mathrm{O}_2}\) during the crystallisation of the parent magmas in different plutons. The plutons are crystallised under varying pressures (6.2–2.4 kbar) and a wide range of temperatures (896–\(718{^{\circ }}\hbox {C}\)) from highly oxidised magmas (log \(f_{\mathrm{O}_2}\) \(-11.2\) to \(-15.4\) bar). The water content of the magma of different plutons varied from 5.0 to 6.5 wt%, consistent with the calc-alkaline nature of the magma. Calc-alkaline nature, high oxygen fugacity and high \(\hbox {H}_{2}\hbox {O}_{{\mathrm{melt}}}\) suggest that these plutons were emplaced in subduction zone environment. The depths of emplacement of these plutons seem to increase from west to east. Petrologic compositions of these granitoids continuously change from enderbite (opx-tonalite: Sarpahari) in the east to monzogranite (Raghunathpur) to syenogranite (Sindurpur) to alkali feldspar granite (Agarpur) in the west. The water contents of the parental magmas of different plutons also increase systematically from east to west. No substantial increase in the depth of emplacement is found in these plutons lying south and north of the major shear zone passing through the study area suggesting the strike-slip nature of the east–west shear zone. 相似文献
8.
The Purulia carbonatite of West Bengal, India is a dyke occurring within the 100 km long South Purulia Shear Zone (SPSZ), which marks the boundary between the Singhbhum Group of Rocks and the Chhotanagpur Granite Gneissic Complex (CGGC). It is composed essentially of calcite with apatite, amphibole, phlogopite, biotite, magnetite and ilmenite as common accessories. Based on optical properties and mineral chemistry two varieties of the amphibole are recognized: magnesiokatophorite and richterite. The latter is characterized by a relatively high content of Si and Na, while the former is enriched in Al and Ca. Such a composition of the amphibole is characteristic for the intermediate to the late stage carbonatite development. These two co-existing amphiboles reflect a sudden variation in total pressure within the magma chamber during the intrusion of the carbonatite dyke. It is inferred that the magnesiokatophorite started crystallizing first along with calcite and apatite. Subsequently, the ascent of carbonatitic magma to a more shallow depth (hypabyssal) resulted in the formation of the richterite. The difference in amphibole composition reflects a variation in the total pressure within the magma chamber that took place during the formation of the Purulia carbonatite. However, an alternative explanation, such as wallrock contamination, or liquid immiscibility, followed by carbonate magma segregation or magma mixing, may also be possible. There is, however, no evidence corroborating such an interpretation. 相似文献
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Turkey lies on the Alpine-Himalayan belt which is one of the most important geothermal belts in the World. Therefore, there are numerous mineral waters in Anatolia where geological and tectonic activities are intense. Archeological studies conducted in Anatolia, which is the cradle of various civilizations, reveal the fact that mineral water has been used as a spa in many areas.The scope of this study is to evaluate mineral waters in Western Anatolia and their use in thermal resorts for balneological purposes. In this respect, 50 thermal waters used in spa centers were analyzed for various physical, chemical and bacteriological parameters.Among the 50 waters tested, 40 are thermomineral waters while 10 are acratothermal waters. Some of these waters have distinct chemical compositions. Their temperatures are between 21 and 90 °C. Various types of mineral water source occur within this region: 5 of these are sulfurous, 1 has carbon dioxide, 29 have fluorine, 1 has iodine and 3 are saliferous. The thermomineral sources with saline characteristics have balneotherapy potential for treating skin illnesses including psoriasis and rheumatological illnesses.Some waters with appreciable bicarbonate and sulfate concentrations can also be used for balneotherapy; for example for use as a cure for chronic inflammatory diseases of gastrointestinal and urinary systems. They could also be used as a cure for prophylactic and metaphylactic treatment of urolithiasis.However, among 38 sampling sites, 12 sites are bacteriologically contaminated. This indicates that regulations governing the protection of such zones are not properly enforced and that water sources within these regions are not sufficiently protected or inspected. 相似文献