Base metal exploration by gravity surveys in a part of the Cuddapah basin (India)—A case study     

G Ramadass  S M Varaprasada Rao  N L Mohan 《Journal of Earth System Science》1986,95(1):131-141

A closely spaced gravity survey was conducted in the Chikativaripally area in the Cuddapah basin, Andhra Pradesh, India for base metal exploration. Analysis of the data using two-dimensional prismatic models suggest a doubly plunging folded structure in the area and also its associated mineralization.  相似文献   

Geomorphic features of a part of Cuddapah and Nellore districts,Andhra Pradesh — Using remote sensing techniques     

S. V. B. Krishna Bhagavan  K. L. Ramana Rao 《Journal of the Indian Society of Remote Sensing》1985,13(2):19-25

An area of about 1000 square kilometres in Cuddapah and Nellore districts of Andhra Pradesh is studied to bring out the different landforms and other geomorphic features, their material content and distribution, the processes that have acted and are acting in the evolution of landscape and ultimately to get an idea of the geomorphic history of the area. The data obtained during the present study is mainly through remote sensing-techniques (Landsat image and airphoto interpretation) with field checks. The study area forms a part of southeastern Cuddapah Basin and consists of structurally disturbed and deformed sedimentary sequence of varied lithology. The impor-tant rock types in the area are granites, gneisses, quartzites, shales, phyllites, limestones and dolomites. The area presently comes under semi-arid climatic zone. The different landforms recognised and mapped in the area are hog-back ridges, piedmont fans, valley fills, river built plain, abandoned channels, point bars, ’ V‘ shaped valleys, piedmont zone, colluvial plain, residual hills, besides lineaments.  相似文献   

Inferred leaf senescence of rice crop and its relationship with grain yield     

P. P. Nageswara Rao  M. V. Krishna Rao  R. S. Ayyangar 《Journal of the Indian Society of Remote Sensing》1985,13(1):1-8

The possibility of detecting change in green cover of rice crop and its relationship with the grain yield was studied using the spectral data collected by an airborne scanner. The spectral data in the form of difference in vegetation index over a 35 day interval, from the time of flowering, was observed to show good relationship between change of green cover (a measure of degree of senescence) and grain yield.  相似文献   

Acute Toxicity of Distillery Effluent on a Freshwater Fish and Three Pond Snails     

B. S. Khangarot  P. S. Rao  S. S. Shekhawat  V. S. Durve 《洁净——土壤、空气、水》1985,13(1):53-58

The LC₅₀ for 12… 96 h of a distillery waste water were determined for Lebistes reticulatus, Lymnaea luteola, Lymnaea acuminata and Viviparus bengalensis in the batch experiment with daily exchange of the medium. The sensitivity of the species increases in the given sequence with values of the LC_{50,96 h} of 10.77 to 3.72 % proportion of wastewater in the medium. Compared with this, with values of the LC_{50,48 h} of 14.06… 15.71 % after 48 h of exposure there is no significant difference in sensitivity, whereas after exposure for 12 and 24 h the sensitivity grows in the following order: V. bengalensis, L. acuminata, L. luteola, Lebistes reticulatus. Toxicity is obviously primarily determined by the sulphides; with increasing time of exposure also the suspended matter and other factors act toxically.  相似文献   

Global temperature changes: relative importance of greenhouse constituents of the atmosphere as calculated with a 1-d radiative-convective model     

M Lal  K C S Rao 《Journal of Earth System Science》1985,94(2):139-145

Most modelling endeavours concerning the CO₂-climate problem address only the question of the climatic response to increasing atmospheric carbon dioxide, while the amounts of other atmospheric gases remain fixed. But associated changes, either climatologically or anthropogenically induced, of minor atmospheric constituents can also be of significance in producing a substantial global warming. We have analysed the climatic response to changes in a number of atmospheric trace gases as they may enhance or counteract CO₂-induced warming if their abundance should change. A comparison of the increase in equilibrium global-mean surface temperature due to plausible changes in the concentration of several trace gases in the atmosphere based on our calculations with a one-dimensional radiative-convective model is presented in this paper. Our results indicate that roughly 35% of global surface warming could be due to changes in trace gases other than CO₂ and water vapour. The possible climatic consequences of the ongoing anthropogenic changes in the minor constituents of the atmosphere are also discussed.  相似文献   

Linkage between rainfall singularities and geomagnetic activity     

R. S. Reddy  K. S. Raja Rao  Bh. V. Ramana Murty 《Meteorology and Atmospheric Physics》1984,33(2-3):127-142

  相似文献   

Studies on the Toxicity of Some Insecticides to a Freshwater Teleost Lebistes reticulatus (PETERS)     

P. K. Gupta  V. S. Mujumdar  P. S. Rao 《洁净——土壤、空气、水》1984,12(6):629-636

In batch tests with daily exchange of the medium the toxicity of endosulfan, lindane, aldrin, chlordane, rogor and novocron is investigated during times of exposure of 12… 96 h. The mean survival periods and the LC₅₀ are determined. Toxicity increases in the following sequence (LC_50,96h) (in mg/1): novocron (22.65), rogor (18.97), chlordane (0.341), aldrin (0.017), lindane (0.0160), endosulfan (0.0027). The following safe concentrations in mg/1 are recommended: 0.0006 endosulfan, 0.0041 lindane, 0.0010 aldrin, 0.1436 chlordane, 5.4086 rogor and 7.2309 novocron.  相似文献   

Injected radiotracer techniques in hydrology     

S. M. Rao 《Journal of Earth System Science》1984,93(3):319-335

Radioactive tracers which have several advantages over conventional tracers made significant contributions to the development of the injected tracer method in hydrology. A review of the nuclear and the physico-chemical characteristics of the possible radiotracer compounds leads us to conclude that the most effective groundwater tracers are tritiated water (HTO),⁸²Br⁻ and⁵⁸Co or⁶⁰Co as a hexacyanocobaltate complex. A discussion of the various case studies in India and abroad covering the three groups of applications mentioned helps us to conclude that well established radiotracer methods with associated interpretational techniques are available for many short range studies in surface and subsurface hydrology.  相似文献   

Noble gas composition in Ogi and Siena meteorites     

J T Padia  C M Nautiyal  M N Rao  T R Venkatesan 《Journal of Earth System Science》1984,93(1):79-82

The elemental and isotopic composition of noble gases in two chondritic meteorites which belong to documented “falls” is reported. Ogi, which belongs to the group of H-chondrites, fell in Saga, Kyushu (Japan) at 11am on 8 June 1741 and Siena which belongs to the group of LL-chondrites, fell in Tuscany (Italy) at 7pm on 16 June 1794. The recovered mass of Ogi and Siena were 14·2 and 4 kg respectively. Their exposure ages are 13±2 m.y. and 13±3 m.y. respectively.  相似文献   

Magnetometric surveys over some iron-ore occurrences in the Eastern Ghats belt of Godavari Districts,Andhra Pradesh     

V Bhaskara Rao  A Lakshmipathi Raju 《Journal of Earth System Science》1984,93(2):159-176

Iron-ore with magnetite as the chief ore mineral occurs in the Precambrians of Eastern Ghats. Vertical magnetometric surveys were carried out to delineate some of the ore bands, in the Ghats belt of Godavari Districts, Andhra Pradesh, around Addatigala, Devipatnam and Tekuru. Interpretation of the magnetic anomalies was based on the tabular models. Ore bands are at shallow depths of around 5m. The deduced inclinations of magnetisation suggest that the magnetisation is largely remanent. The intensities of magnetisation are in the range of 5 to 10·5×10^?3 emu and agree well with the laboratory measurements on the ore samples. At Devipatnam and Tekuru the magnetic background seems to be high. At Tekuru the ore band appears to be very limited in depth extent. The limited depth extent coupled with high magnetic background explains the anomaly which is not so prominent. It is concluded that in such areas, it is only the high grade magnetite ore bands of considerable depth extent that can be successfully delineated by the magnetic method.  相似文献