Geochemistry and tectonic significance of mafic volcanic rocks of the Hindoli belt, southeastern Rajasthan: Implications for continent assembly     

Mahshar Raza  Mohd. Zuhaib Siddiqui 《Journal of the Geological Society of India》2012,80(4):553-562

Mafic volcanic rocks that occur within the sedimentary pile of the Hindoli Group were analyzed for major and trace elements (including REE) to establish tectonic setting of volcanism during the early Proterozoic history of the North Indian Craton. The mafic volcanics are sub-alkaline showing compositional variation from picrobasalt to basalt. They are LREE enriched with (La/Yb)_N ratio ranging from 4.67?C6.19 (avg.5.27) and exhibit slightly concave REE patterns relative to chondrite. The multi-element patterns of these mafic volcanic rocks display relative enrichment in Th and LREE and negative anomalies of Nb and P. These geochemical characteristics are consistent with a subduction related origin. Various variation diagrams, involving immobile trace elements, distinguish the Hindoli lavas as arc basalt. However, their Ti and Nb contents are higher than those of subduction related magmas. Probably the wedge melting, along with mixing of rising asthenosphere might have produced these characteristics. It is suggested that the Hindoli basin originated by rifting of island- arc lithosphere, caused by rising plume in an extensional back arc region. Based on the results of the present geochemical study, it is proposed that in the early Proterozoic the Mewar block had an active-type continental margin on its present eastern side. The continental magmatic arcs and intra-arc basins developed on this margin were subsequently incorporated into the Mewar protocontinent. Possibly, the plate carrying the Bundelkhand block subducted beneath the eastern margin of the Mewar block, resulting in the final amalgamation of the two blocks along Great Boundary Fault zone or Banas Dislocation Zone. The arc related volcanism of north Indian shield at about 1850?C1832 Ma, appears to represent the global subduction event, which resulted in the amalgamation and formation of Columbia supercontinent.  相似文献   

Per-pixel and object-oriented classification methods for mapping urban land cover extraction using SPOT 5 imagery     

Mustafa Neamah Jebur  Helmi Zulhaidi Mohd Shafri  Mahyat Shafapour Tehrany 《国际地球制图》2013,28(7):792-806

To have sustainable management and proper decision-making, timely acquisition and analysis of surface features are necessary. Traditional pixel-based analysis is the popular way to extract different categories, but it is not comparable by the achievements that can be achieved through the object-based method that uses the additional characteristics of features in the process of classification. In this paper, three types of classification were used to classify SPOT 5 satellite image in mapping land cover; Support vector machine (SVM) pixel-based, SVM object-based and Decision Tree (DT) pixel-based classification. Normalised Difference Vegetation Index and the brightness value of two infrared bands (NIR and SWIR) were used in manually developed DT classification. The classification of the SVM (pixel based) was generated using the selected groups of pixels that represent the selected features. In addition, the SVM (object based) was implemented by using radial-based function kernel. The classified features were oil palm, rubber, urban area, soil, water and other vegetation. The study found that the overall classification of the DT was the lowest at 69.87% while those of SVM (pixel based) and SVM (object based) were 76.67 and 81.25%, respectively.  相似文献   

Wave climate simulation for southern region of the South China Sea   总被引：2，自引：0，他引：2  

Ali Mirzaei  Fredolin Tangang  Liew Juneng  Muzneena Ahmad Mustapha  Mohd Lokman Husain  Mohd Fadzil Akhir 《Ocean Dynamics》2013,63(8):961-977

This study investigates long-term variability and wave characteristic trends in the southern region of the South China Sea (SCS). We implemented the state-of-the art WAVEWATCH III spectral wave model to simulate a 31-year wave hindcast. The simulation results were used to assess the inter-annual variability and long-term changes in the SCS wave climate for the period 1979 to 2009. The model was forced with Climate Forecast System Reanalysis winds and validated against altimeter data and limited available measurements from an Acoustic Wave and Current recorder located offshore of Terengganu, Malaysia. The mean annual significant wave height and peak wave period indicate the occurrence of higher wave heights and wave periods in the central SCS and lower in the Sunda shelf region. Consistent with wind patterns, the wave direction also shows southeasterly (northwesterly) waves during the summer (winter) monsoon. This detailed hindcast demonstrates strong inter-annual variability of wave heights, especially during the winter months in the SCS. Significant wave height correlated negatively with Niño3.4 index during winter, spring and autumn seasons but became positive in the summer monsoon. Such correlations correspond well with surface wind anomalies over the SCS during El Nino events. During El Niño Modoki, the summer time positive correlation extends northeastwards to cover the entire domain. Although significant positive trends were found at 95 % confidence levels during May, July and September, there is significant negative trend in December covering the Sunda shelf region. However, the trend appears to be largely influenced by large El Niño signals.  相似文献   

Screening Indian Mustard Genotypes for Phytoremediating Arsenic‐Contaminated Soils     

Mohd Kafeel Ahmad Ansari  Hong‐Bo Shao  Shahid Umar  Altaf Ahmad  Shahid Hussain Ansari  Muhammad Iqbal  Gary Owens 《洁净——土壤、空气、水》2013,41(2):195-201

Ten Indian mustard (Brassica juncea L.) genotypes were screened for their phytoremediation potential for arsenic (As) contaminated water under laboratory‐controlled conditions. The genotypes were grown in a hydroponic chamber for 20 days in 250‐mL beakers containing As‐contaminated water. During plant development, changes in plant growth, biomass, and total As were evaluated. Of the 10 genotypes (Pusa Agrani, BTO, Pusa Kranti, Pusa Bahar, Pusa Bold, Pusa Basant, Pusa Jai Kisan, Arka Vardhan, Varuna, and Vaibhav) Pusa Jai Kisan was the most effective in phytoremediating As‐contaminated water under hydroponic conditions. This will provide new information for Indian mustard genotypes for phytoremediating As‐contaminated soils.  相似文献   

Watershed prioritization using morphometric and land use/land cover parameters: A remote sensing and GIS based approach   总被引：4，自引：0，他引：4  

Akram Javed  Mohd Yousuf Khanday  Subah Rais 《Journal of the Geological Society of India》2011,78(1):63-75

Jaggar watershed is a constituent of the Gambhir river basin, in eastern Rajasthan and covers an area of 352.82 km², representing arid climate. The drainage network is dendritic to sub-dendritic pattern however parallel to sub-parallel has also developed locally. The Jaggar watershed has been divided into fourteen sub-watersheds, designated as SW1 to SW14, for prioritization purpose. The prioritization of the sub-watersheds has been done on the basis of morphometric analysis and land use/land cover categories. Various morphometric parameters (linear and shape) have been determined for each sub-watershed and assigned rank on the basis of value/relationship with erodibility so as to arrive at a compound value for final ranking of the sub-watersheds. Land use/land cover mapping has been carried out using IRS LISS III data of 1998. Based on morphometric and land use/land cover analysis and their ranks, the subwatersheds have been classified into four categories as very high, high, medium and low in terms of priority for conservation and management of natural resources. The prioritization results based on morphometry reveal that only SW7 and SW10 fall under very high priority, whereas SW6, SW11 and SW13 fall under very high priority on the basis of land use/land cover analysis. However on the integration of morphometry and land use/land cover only SW14 show common priority whereas rest have little or no correlation.  相似文献   

Aquifer hydraulic conductivity estimation from surface geoelectrical measurements for Krauthausen test site, Germany   总被引：2，自引：0，他引：2  

Sri Niwas  B. Tezkan  Mohd Israil 《Hydrogeology Journal》2011,19(2):307-315

The physical explanation is presented for two types of theoretical equations which encompass a direct and an inverse relationship between the hydraulic conductivity and electrical resistivity of an aquifer. Using the theory of direct current (DC) resistivity prospecting, it is shown that a direct relation exists if the bulk of the current flow is in the vertical direction, whereas the inverse relation exists if the current is in the horizontal direction. Consequently, the relation in question is direct in the case of a relatively conducting basement and inverse in the case of a comparatively resistive basement. Then, the aquifer hydraulic conductivity for the hydrogeologically well-studied area of Krauthausen in Germany is estimated by two different techniques using surface geoelectrical data. The estimated values are compared with those conventionally determined by a pump test experiment and it can be concluded that the estimation is better whenever geoelectrical data are used.  相似文献   

Composition of selected heavy metals in road dust from Kuala Lumpur city centre   总被引：1，自引：1，他引：0  

Nur Mun’im Mohd Han  Mohd Talib Latif  Murnira Othman  Doreena Dominick  Noorlin Mohamad  Hafizan Juahir  Norhayati Mohd Tahir 《Environmental Earth Sciences》2014,72(3):849-859

This study was carried out in order to determine the concentration of heavy metals, e.g., lead (Pb), cadmium (Cd), copper (Cu), zinc (Zn), iron (Fe), manganese (Mn), nickel (Ni) and chromium (Cr) in road dust in Kuala Lumpur’s city centre. Samples were collected from four sampling locations, each of which had four sampling points and three replications. Heavy metals from different fractions of particles separated by different diameter sizes: d < 63 μm (Fraction A), 63 < d < 125 μm (Fraction B) and 125 < d < 250 μm (Fraction C) were analyzed using inductively coupled plasma mass spectrometry. The results from this study showed that concentration of heavy metals was dominated by the smallest particle size: <63 μm and that Fe was the most abundant heavy metal overall, followed by Cu > Mn > Zn > Pb > Ni > Cr > Cd. The fact that Cd had the highest enrichment factor value (EF) for all particle sizes indicates that anthropogenic activities contributed to the presence of this metal. There was also a higher EF value for heavy metals in small particle (Fraction A), compared to Fraction B and C, which suggests that fine particles were being produced through anthropogenic activities. Cluster analysis and principal component analysis demonstrated the likelihood of the heavy metals detected in the road dust, originating from road traffic and industrial activities.  相似文献   

Particle tracking analysis of river–aquifer interaction via bank infiltration techniques     

Mohd Khairul Nizar Shamsuddin  Saim Suratman  Mohamad Pauzi Zakaria  Ahmad Zaharin Aris  Wan Nor Azmin Sulaiman 《Environmental Earth Sciences》2014,72(8):3129-3142

Induced bank infiltration (BI) is commonly implemented in other countries, but remains new and unexplored in Malaysia. Increasing river pollution could affect drinking water resources. Given the threat of pollution to raw water sources, applying induced BI to sustain water management is essential. This paper presents a case study of the BI method, which evaluates the effects of groundwater pumping and BI operation on the installation of wells as well as determines the effect of pumping rate on flow paths, travel time, the size of the pumping and capture zone delineation, and groundwater mixing in a pumping well in Jenderam Hilir, Malaysia. The proposed method performs infiltration safely and achieves the ideal pumping rate. Numerical modeling packages, MODFLOW and MODPATH (particle tracking) were used. Results indicate that the migration of river water into the aquifer is generally slow and depends on the pumping rate and distance from well to the river. Most water arrives at the well by the end of a pumping period of 1–5 days at 3,072 m³/day for test wells DW1 and DW2, and during simultaneous pumping for DW2 and PW1 for a well located 36 and 18 m, respectively, from the river. During the 9.7-day pumping period, 33 % of the water pumped from the DW1 well was river water, and 38 % from DW2 throughout 4.6 days was river water. The models provide necessary information for water operators in the design and construction of pumping and sampling schedules of BI practices.  相似文献   

Tenfold cross validation artificial neural network modeling of the settlement behavior of a stone column under a highway embankment   总被引：1，自引：1，他引：0  

Zamri Chik  Qasim A. Aljanabi  Anuar Kasa  Mohd Raihan Taha 《Arabian Journal of Geosciences》2014,7(11):4877-4887

Construction of embankments in engineering structures on soft clay soils normally encounters problems related to excessive settlement issues. The conventional methods are inadequate to analyze and predict the surface settlement when the necessary parameters are difficult to determine in the field and in the laboratory. In this study, artificial neural network systems (ANNs) were used to predict settlement under embankment load using soft soil properties together with various geometric parameters as input for each stone column (SC) arrangement and embankment condition. Data from a highway project called Lebuhraya Pantai Timur2 in Terengganu, Malaysia, were investigated. The FEM package of Plaxis v8 program analysis was utilized. The actual angle of internal friction, spacing between SC, diameter of SC, length of SC, and height of embankment were used as the input parameters, and the settlement was used as the main output. Non cross validation (NCV) and tenfold cross validation (TFCV) were used to build the ANN model. The results of the TFCV model were more accurate than those of the NCV model. Comparisons made with the predictions of the Priebe model showed that the proposed TFCV model could provide better predictions than conventional methods.  相似文献   

Simulation of horizontal well performance using Visual MODFLOW   总被引：2，自引：2，他引：0  

Wan Mohd Zamri W. Ismail  Ismail Yusoff  Bahaa-eldin E. A. Rahim 《Environmental Earth Sciences》2013,68(4):1119-1126

A proposed horizontal well or radial collector well installation in shallow aquifers to enhance water withdrawal rates in Pintu Geng well field in Kelantan, Malaysia was simulated using the Drainage Package of MODFLOW groundwater model. The modelling exercise aimed at identifying an optimum pumping rate that would safely achieve the desired drawdown of less than 2 m in an area of 300 m radius surrounding the Pintu Geng horizontal collector well. The model also would serve as a basis for the design of the horizontal well components. High degree of grid refinement for the well location is needed to simulate the real field installation. However, for the purpose of designing water withdrawal systems, it is important to obtain the correct production rate of these wells for a given drawdown. A transient groundwater flow model was calibrated and validated with few assumptions of the horizontal well hydraulic properties. The model demonstrates that under natural flow condition at ?3 m depth, the six collectors (drains) tap a volume of 19,200–43,700 m³/day. A steady-state model was also developed to predict the capture zone delineation. Attention is also given to the impact of the well installation to the surrounding 300 m radius by inspecting the degree of the drawdown.  相似文献