首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   7篇
  免费   0篇
地球物理   1篇
地质学   5篇
自然地理   1篇
  2019年   1篇
  2016年   2篇
  2014年   1篇
  2009年   1篇
  2006年   1篇
  1997年   1篇
排序方式: 共有7条查询结果,搜索用时 203 毫秒
1
1.
I.TheStudyArea:SagarDivisionSagardivisionliesinthenorthcentralpartofMadhyaPradeshbetween23°10′and26°35′Nlatitudesand78°04and80°38′Elongitudes.Thegeographicalaresis38223km2whichissbout8.65percentoftheState.TheSagaradministrativedivisionconsistsoffivedistrictsviz.Sag…  相似文献   
2.
3.
4.
Surface exploration techniques have been key contributors in discovering mineral deposits over the past three decades. However, in the last decade there has been a growing emphasis on integrating remote sensing, geological, geophysical and geochemical exploration techniques to compliment them in identifying concealed deposits. Successful integrated exploration requires putting mappable petrophysical property contrasts in terms of geological and geochemical process that could be associated with different mineralisation environment. The Precambrian Gangpur basin comprising volcanic free sedimentary sequence is considered as a potential geological setting for hosting uranium mineralisation. The Gangpur basin with metasediments of low to medium metamorphic grade classified as the Gangpur Group are known for hosting manganese, limestone and lead-zinc deposits. Uranium mineralization is reported in limonitic carbonaceous phyllite and sheared quartzite of Kumarmunda Formation at Jhamankele-Bhalulata areas. Several uranium anomalies have been associated with gossan at Kaedarpani, Jamdra and in ferruginised laterite at Badekachar, Jarmal, Jhagarpur, Kadorpani, Karamabahal, Tetelkela & Kumtinunda. In the present study geological, geophysical and remote sensing data sets are processed and integrated with other available data to delineate target zones for uranium exploration. Even though direct detection of uranium mineralisation remains unresolved in exploration strategy, instead it is becoming increasingly instructive to focus on mapping suitable depositional environments. The enhanced satellite imagery is interpreted in terms of thematic layers viz. trend lines, lineaments, faults and geological contacts. The aeromagnetic data is processed and interpreted thematic layers of magnetic breaks and linears from total magnetic intensity (TMI), the reduced to pole (RTP), tilt derivative and amplitude of analytical signal grid images. The radiometric data is processed based on their broad lithology and radio-elemental distribution maps viz. count maps, ratio maps, ternary (%K-eTh-eU) and eU/K ? eU/eTh ? eU images are generated to aid in mapping uranium favourability zones. The favourability image zones with high eU/K, eU/eTh and eU counts zones are classified into class based on statistics and anomalous high zones are picked up as uranium favourable locales. The thematic layers of geological contacts, lineaments and faults interpreted from satellite imagery, magnetic linears interpreted from aeromagnetic data and uranium favourability zone extracted from Airborne Gamma Ray Spectrometric (AGRS) data are overlaid. Based on spatial association of favourable features few locals are delineated for uranium exploration.  相似文献   
5.
Most of the studies on Artificial Neural Network (ANN) models remain restricted to smaller rivers and catchments. In this paper, an attempt has been made to correlate variability of sediment loads with rainfall and runoff through the application of the Back Propagation Neural Network (BPNN) algorithm for a large tropical river. The algorithm and simulation are done through MATLAB environment. The methodology comprised of a collection of data on rainfall, water discharge, and sediment discharge for the Narmada River at various locations (along with time variables) and application to develop a threelayer BPNN model for the prediction of sediment discharges. For training and validation purposes a set of 549 data points for the monsoon (16 June-15 November) period of three consecutive years (1996–1998) was used. For testing purposes, the BPNN model was further trained using a set of 732 data points of monsoon season of four years (2006–07 to 2009–10) at nine stations. The model was tested by predicting daily sediment load for the monsoon season of the year 2010–11. To evaluate the performance of the BPNN model, errors were calculated by comparing the actual and predicted loads. The validation and testing results obtained at all these locations are tabulated and discussed. Results obtained from the model application are robust and encouraging not only for the sub-basins but also for the entire basin. These results suggest that the proposed model is capable of predicting the daily sediment load even at downstream locations, which show nonlinearity in the transportation process. Overall, the proposed model with further training might be useful in the prediction of sediment discharges for large river basins.  相似文献   
6.
Flood frequency analysis is a pre-requisite for setting up and safeguarding of many hydraulic structures, such as dams, barrages, check-dams, culverts and urban drainage systems. In the flood frequency analysis, partial duration series (PDS) may be considered when dealing with values exceeding certain limits causing floods. In fact, the PDS is capable of getting more information about extreme events than the annual maximum series (AMS). Additionally, an assumption that, the magnitude of the extreme events of a PDS is best described by a generalized Pareto (GP) distribution. The present work investigates the at-site flood frequency analysis to find the average number of peaks (λ) for modelling the PDS on the basis of the PDS/GP assumption and variability in the GP parameters coupled with the quantile estimation with an increase in the value of average number of peaks (λ) each year in the Mahanadi river system, Odisha, India. Also, to verify the PDS/GP assumption we tested seven different frequency distributions (Exponential, Gumbel, logistics, generalized extreme value (GEV), Lognormal (LN), generalized logistics (GL) and Pearson Type 3). Extensive daily discharge data collected from 23 gauging sites were used for the analysis. The results indicate precision and stability of GP distribution parameters for λ?=?4 for almost all the discharge sites. The peak flood estimated for various return periods in the Mahanadi river system using GP distribution is endowed with high correlation statistics for this λ value.  相似文献   
7.
An integrated approach to resolve the kinematics of the controversial Achankovil Shear Zone (AKSZ) has been attempted involving remote sensing data, shaded relief topo-maps, ground details of lithology and mesoscopic structures. An excellent correlation of structural trends exists on all scales of observation. The AKSZ is distinctly defined by NW–SE trending foliation fabrics with steep dips to southwest. The adjacent Madurai block and Trivandrum block show contrasting lithological and structural characteristics as shown in structural cross-sections.The mesoscopic structural studies reveal the presence of sub-horizontal stretching lineations, asymmetric structures like S–C′ fabrics, porphyroclasts, ‘S’ shaped folds and shear bands confirming the strike-slip component of shear along AKSZ. The deformation undergone by the AKSZ could be described in terms of an initial dextral deformation — D1, reactivated and superimposed by sinistral kinematics — D2, which is also supported by megascopic structural interpretation of remote sensing data. The megascopic structural interpretation of AKSZ displays en-echelon pattern of lineaments with right overstepping arrangement, which can be interpreted as an evidence of the latest sinistral transpressional deformation.  相似文献   
1
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号