美国俄亥俄州土壤有机碳密度空间分布(英文)   总被引：2，自引：1，他引：1  

Sandeep KUMAR  Rattan LAL  Desheng LIU  Rashid RAFIQ 《地理学报(英文版)》2013,23(2):280-296

Historical database of National Soil Survey Center containing 1424 geo-referenced soil profiles was used in this study for estimating the organic carbon(SOC) for the soils of Ohio,USA.Specific objective of the study was to estimate the spatial distribution of SOC density(C stock per unit area) to 1.0-m depth for soils of Ohio using geographically weighted regression(GWR),and compare the results with that obtained from multiple linear regression(MLR).About 80% of the analytical data were used for calibration and 20% for validation.A total of 20 variables including terrain attributes,climate data,bedrock geology,and land use data were used for mapping the SOC density.Results showed that the GWR provided better estimations with the lowest(3.81 kg m 2) root mean square error(RMSE) than MLR approach.Total estimated SOC pool for soils in Ohio ranged from 727 to 742 Tg.This study demonstrates that,the local spatial statistical technique,the GWR can perform better in capturing the spatial distribution of SOC across the study region as compared to other global spatial statistical techniques such as MLR.Thus,GWR enhances the accuracy for mapping SOC density.  相似文献   

Reservoir characterization of basal sand zone of lower Goru Formation by petrophysical studies of geophysical logs     

Mureed Hussain  Nisar Ahmed  Wang Yan Chun  Perveiz Khalid  Azhar Mahmood  Sajid Rashid Ahmad  Umair Rasool 《Journal of the Geological Society of India》2017,89(3):331-338

The lower Indus basin is one of the largest hydrocarbon producing sedimentary basins in Pakistan. It is characterized by the presence of many hydrocarbon-bearing fields including clastic and carbonates proven reservoirs from the Cretaceous to the Eocene age. This study has been carried out in the Sanghar oil field to evaluate the hydrocarbon prospects of basal sand zone of lower Goru Formation of Cretaceous by using complete suite of geophysical logs of different wells. The analytical formation evaluation by using petrophysical studies and neutron-density crossplots unveils that litho-facies mainly comprising of sandstone. The hydrocarbons potentialities of the formation zone have been characterized through various isoparameteric maps such as gross reservoir and net pay thickness, net-to-gross ratio, total and effective porosity, shaliness, and water and hydrocarbons saturation. The evaluated petrophysical studies show that the reservoir has net pay zone of thickness range 5 to 10 m, net-togross ratio range of 0.17 to 0.75, effective porosity range of 07 to 12 %, shaliness range of 27 to 40 % and hydrocarbon saturation range of 12 to 31 %. However, in the net pay zone hydrocarbon saturation reaches up to 95%. The isoparametric charts of petrophysically derived parameters reveal the aerial distribution of hydrocarbons accumulation in basal sand unit of the lower Goru Formation which may be helpful for further exploration.  相似文献   

A review on 3D terrain visualization of GIS data: techniques and software     

Che Mat RUZINOOR  Abdul Rashid Mohamed SHARIFF  Biswajeet PRADHAN  Mahmud RODZI AHMAD  Mohd Shafry Mohd RAHIM 《地球空间信息科学学报》2012,15(2):105-115

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Hydrochemical characteristics and seasonal variations in groundwater quality of an alluvial aquifer in parts of Central Ganga Plain,Western Uttar Pradesh,India   总被引：1，自引：0，他引：1  

Rashid Umar  Izrar Ahmed  Fakhre Alam  Mohammad Muqtada Khan 《Environmental Geology》2009,58(6):1295-1300

The present study was undertaken to assess major ion chemistry of groundwater in parts of the Central Ganga Plain and observe seasonal variations in its chemical quality. Systematic sampling was carried out during November 2005 and June 2006. The major ion chemistry of groundwater shows large variations, so much so that at times the meteoric signature seems to be completely obliterated. In many samples the concentrations of SO₄, NO₃ and F are above the permissible limit for human consumption. The graphical treatment of major ion chemistry helps in identifying four types of groundwater. All possible ionic species such as NaCl, KCl, NaHCO₃, NaSO₄, KNO₃, NaNO₃, CaHCO₃, MgHCO₃, MgSO₄ are likely to occur in groundwater system. The observed chemical variations may be attributed to sediment water interaction, ion exchange, dissolution mechanisms and anthropogenic influences such as application of fertilizers and effluents from sugar factories and paper mills. A general increase in TDS is observed in samples during June 2006. The increase in salinity is attributed to evaporation from water table, irrigation return flows, anthropogenic activities and below average rainfall in 2005 and 2006. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

Geochemistry and genesis of sulphide ore deposits in Sharosh Village,Qandil Series,Kurdistan Region,NE Iraq     

Tola A. Mirza  Stavros P. Kalaitzidis  Sarkhel H. Mohammed  Saman Gh. Rashid  Xenia Petrou 《Arabian Journal of Geosciences》2017,10(19):428

The low-grade base metal sulphide Cu–Zn–Pb and Fe mineralization of Qandil Series develop in shear zones that occur in formations of the north-western part of the Zagros Orogen. This sulphide mineralization occurs either as quartz vein type or disseminated type associated with metamorphic rocks (marbles and phyllites). This study aims to characterize these sulphide-rich ores by means of their mineralogical and geochemical features, including also the features of the corresponded host formations and those of marbles (calcitic and dolomitic) and phyllites. Petrographical data indicate the presence of Cu, Zn, Pb and Fe sulphides in hydrothermal quartz (±calcite) veins of different generations. Geochemical data of surface samples indicate enrichment of Cu and Fe in shear zones with low concentrations in Zn and Pb. The REE data indicate that the genesis of these sulphide ores took place in a hydrothermal system and was generally attributed to high temperature (> 250 °C).The mineralization seems to be fault-controlled, which is favoured by the significant tectonic deformation of the area.  相似文献   

Integrated multi-parameter approach for delineating groundwater potential zones in a crystalline aquifer of southern India     

Mehnaz Rashid  Min-Hui Lo  Shakeel Ahmed 《Arabian Journal of Geosciences》2017,10(22):489

Groundwater resources in the semi-arid regions of southern India are under immense pressure due to large-scale groundwater abstraction vis-à-vis meager rainfall recharge. Therefore, understanding and evaluating the spatial distribution of groundwater is essential for viable utilization of the resource. Here, we assess groundwater potential at the watershed scale, in a semi-arid environment with crystalline aquifer system without a perennial surface water source using remote sensing, geophysical, and GIS-based integrated multi-parameter approach. GIS-based weighed overlay analysis is performed with input parameters, viz., geology, geomorphology, lineament density, land use, soil, drainage density, slope, and aquifer thickness. The watershed is categorized into four zones, namely, “very good” (GWP4), “good” (GWP3), “moderate” (GWP2), and “low” (GWP1) in terms of groundwater potential. Overall, ~?70% of the study area falls under moderate to low groundwater potential, indicating a serious threat to the future availability of the resource. Therefore, serious measures are required for maintaining aquifer resilience in this over-exploited aquifer (e.g., restricting groundwater withdrawal from GWP1 and GWP2 zones). Further, as the aquifer is under tremendous anthropogenic pressure, rainwater harvesting and artificial recharge during monsoon are advocated for sustainable aquifer management. Due to the direct dependence of crop production vis-à-vis farmer economy on groundwater, this study is an important step towards sustainable groundwater management and can be applied in diverse hydrological terrains.  相似文献   

A Neural-Network Approach to the Determination of Aquifer Parameters   总被引：8，自引：0，他引：8  

Abd. Rashid Abd. Aziz  Kau-Fui Vincent Wong 《Ground water》1992,30(2):164-166

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On the occurrence and strati graphic position of Permo-Carboniferous tillites in Saudi-Arabia     

Dr. Ahmed H. Helal 《International Journal of Earth Sciences》1964,54(1):193-207

Summary While engaged in geological investigations in the Mundafan and Beni Khatma areas (Saudi Arabia), large igneous and metamorphic erratics of more than 2 m diameter were noticed widely scattered over a length of more than 100 km. Two well defined horizons containing these boulders were noticed in different sections in the Beni Khatma area within the Wajid Sandstone which is of Permian or older age.These boulders, which are both acid to basic igneous and metamorphic rocks, are encountered in nonmarine sequences. The boulders must have been transported from the Arabian Shield lying more than 100 km to the west of the erratics.The very abundant and wide spread nature of the isolated pebbles, cobbles, and boulders and their embedding in a sandy, clayey and silty matrix may constitute strong evidence of ice rifting and frigid climate. Adding to that, that the Mundafan and Beni Khatma areas lie in a region of stable, nonorogenic, cratonic character which never suffered from volcanism or orogeny, present glaciation as the plausible mechanism of transportation of the erratics.These Permo-Carboniferous Arabian tillites are very important as a temporal equivalent to southern hemisphere Permo-Carboniferous glaciations, i. e. South Africa, India and Australia which show substantial field evidence of the late Paleozoic glaciation.

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Zusammenfassung Während geologischer Untersuchungen im Gebiet von Mundafan und Beni Khatma (Saudi-Arabien) wurden erratische Blöcke von mehr als 2 m Durchmesser in weiter Verbreitung nachgewiesen. Sie erscheinen im Anstehenden in 2 abgrenzbaren Horizonten in verschiedenen Profilen im Raum von Beni Khatma. Diese Horizonte sind dem Wajid-Sandstein eingeschaltet, der nach altersmä\ig eindeutigen Hangendschichten noch permisches oder vorpermisches Alter hat und dem Kristallin des Arabischen Schildes aufliegt.Die Erratica (Granite, Basite) sind auf ein 100 km westlich liegendes Muttergestein — Komplex des Arabischen Schildes — zurückzuführen. Sortierung im Profile, Rundungsgrad und Schrammungen deuten auf Tillite. Die unterschiedlichen Geschiebetypen in den beiden auskartierten Niveaus weisen auf etwas verschiedene Liefergebiete im Westen. Die Blöcke sind danach nicht vom autochthonen Kristallin des unmittelbaren Untergrunds — etwa als ehemalige Hangschuttbildung — herzuleiten und zudem vom Präkambrium durch Gestein in der Nubischen Sandsteinfazies getrennt.Die Erratica werden mit einer permo-karbonischen Eisdrift in Beziehung gebracht (vielleicht sind sie auch z. T. fluvio-glazial) und bieten damit einen weitern Anhaltspunkt für paläogeographische und paläoklimatische Diskussionen im Zusammenhang mit der permo-karbonischen Vereisung Gondwanalands.

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Short notice has been published already in Eiszeit u. Gegenwart,14, 121–123, 1963.  相似文献   

Turbulent mixing condensation nucleus counter     

Rashid Mavliev 《Atmospheric Research》2002,62(3-4)

The construction and operating principles of the Turbulent Mixing Condensation Nucleus Counter (TM CNC) are described. Estimations based on the semiempirical theory of turbulent jets and the classical theory of nucleation and growth show the possibility of detecting particles as small as 2.5 nm without the interference of homogeneous nucleation. This conclusion was confirmed experimentally during the International Workshop on Intercomparison of Condensation Nuclei and Aerosol Particle Counters (Vienna, Austria). Number concentration, measured by the Turbulent Mixing CNC and other participating instruments, is found to be essentially equal.  相似文献   

Estimation of Anthropogenic Influences in Groundwater Quality of Shallow Aquifers of Moradabad City,Western Uttar Pradesh     

Naseemus Saba  Rashid Umar  Ahsan Absar 《Journal of the Geological Society of India》2018,91(6):711-716

The present work has been carried out in Moradabad, one of the important cities in the state of Uttar Pradesh. The main focus of the study is to estimate the extent of anthropogenic contamination in shallow groundwater of the area. For this purpose, total 188 groundwater samples collected from handpumps in pre- and post monsoon period of 2012 and 2013 (47 in each season) were analyzed for physico-chemical parameters such as pH, EC, TDS, major cations (Ca, Mg, Na, and K) and anions (Cl, HCO₃, SO₄, NO₃ and F). The results of the analysis suggested that groundwater is slightly alkaline, hard to very hard in nature, average TDS values were found to be more than 1000 mg/l, which gives a clear evidence of anthropogenic influences. To estimate the extent of contamination, the information on relatively unpolluted groundwater systems occurring in different terrains including Ganga plain where the groundwater was relatively unaffected by anthropogenic activities is used. The estimated pristine chemical composition of groundwater of different terrains used in the present study was compared with the groundwater of Moradabad city. This comparison showed that Moradabad city with the highest Na, K, Cl, SO₄ and NO₃ values being 440 mg/l, 96 mg/l, 537 mg/l, 537 mg/ l and 244 mg/l, respectively, is one of the most polluted urban centres within the Ganga plain. It may be suggested that values of > 50 mg/l for Na, > 10 mg/l for K, > 25 mg/l for Cl, > 50 mg/l for SO₄ and > 10 mg/l for NO₃ have their respective sources in anthropogenic activities such as agricultural in the peripheral region, human and animal wastes, leakages from drains and septic tanks, landfill leachates and industrial effluents.  相似文献