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111.
This study investigated morphological variation and biomass accumulation that occurred in Sida acuta and Chromolaena odorata plants grown in lead polluted soil under organic fertilizer amendment. The study was carried out in the screen house at the Biological Gardens of the Obafemi Awolowo University, Ile-Ife, Osun State. The experiment was a factorial combination of one heavy metal (Pb) at five levels of concentration (0, 200, 400, 800 and 1,000 mg/kg) in a completely randomized design, and were replicated three times for each of the two plants and two levels (0 g/kg and 9.4 g/kg) of organic fertilizer (OBD-Plus). Each pot was filled with 5 kg of air-dried and sieved soil and placed on a plastic tray for the collection of excess water. Two weeks after planting, seedlings of uniform height were transplanted from the nursery to experimental pots at the rate of one seedling per pot and grown for 10 weeks. The growth parameters of the plants were biomonitored for 7 weeks. After 10 weeks of treatment, the plants were harvested and dried to calculate the biomass accumulation. The two plant species performed better under fertilizer application than without it. For each of the plant species the growth parameters decreased as the levels of Pb concentration increased. Furthermore, the plants' biomass decreased significantly (p<0.05) as the levels of Pb concentration increased. The organic fertilizer helped to improve the plants' performance in lead-polluted soil. 相似文献
112.
The Lajeado Group in the Ribeira Belt,southeastern Brazil,corresponds to an open-sea carbonate platform,comprised of seven overlapping siliciclastic and carbonatic formations,intruded in its upper portion by the Apiai Gabbro.These rocks have a Neoproterozoic tectonometamorphic overprint related to arc magmatism and the Brasiliano collisional orogeny.Geochronological constraints are given by new UPb SHRIMP and LA-ICP-MS data for Lajeado Group detrital zircons and for magmatic zircons from the Apiai Gabbro.The youngest detrital zircons in the Lajeado Group are 1400-1200 Ma,and constrain its maximum age of deposition to be 1200 Ma,whereas the 877 ± 8 Ma age for magmatic zircons in the Apiai Gabbro give the minimum age.Detritus source areas are mainly Paleoproterozoic(2200-1800 Ma)with some Archean and Mesoproterozoic contribution(1500-1200 Ma),with distal or tectonic stable cratonic character.The Lajeado Group should be a Stenian-Tonian carbonate platform passive margin of a continent at this time,namely the Columbia/Nuna or the Rodinia.The Apiai Gabbro displays similar age to other intrusive basic rocks in the Lajeado and Itaiacoca groups and represents tholeiitic MORB-like magmatism that we relate to the initial break-up of a Mesoproterozoic continent and the formation of the Brasiliano oceans. 相似文献
113.
E.A.Lalla G.Lopez-Reyes A.Sansano A.Sanz-Arranz J.Martínez-Frías J.Medina F.Rull-Pérez 《地学前缘(英文版)》2016,7(4):673-681
A detailed vibrational Raman-IR spectroscopic and diffractional analyses have been performed on basalts from two locations from Tenerife Island:(1) the Arenas Negras volcano which belongs to the historical eruption not showing visible alteration and(2) Pillow Lavas zone from Anaga Massif which shows a clearly fluid-rock interaction caused by submarine alteration.These places have been extensively studied due to its similarity with the surface of Mars.The analysis is based on the mineral detection of selected samples by a Micro-Raman study of the materials.The complementary techniques have confirmed the mineralogy detected by the Raman measurement.The results show a volcanic environment behavior with primary phases like olivine,pyroxene,and feldspar/plagioclase.Moreover,the presence of accessory minerals or secondary mineralization like phosphate,iron oxides,zeolite or carbonates shows the alteration processes on each outcrop.The variation in the crystallinity and amorphous phases is related to fluid-rock interaction caused by hydrothermal episodes and external weathering processes,which shows several analogies with the ancient volcanic activity from Mars. 相似文献
114.
Daniel A.Gregori Bernhardt Saini-Eidukat Leonardo Benedini Leonardo Strazzere Mercedes Barros José Kostadinoff 《地学前缘(英文版)》2016,7(4):621-638
Structural analyses in the northern part of the North Patagonia Massif,in the foliated Caita Co granite and in La Sena and Pangare mylonites,indicate that the pluton was intruded as a sheet-like body into an opening pull-apart structure during the Gondwana Orogeny.Geochronological studies in the massif indicate a first,lower to middle Permian stage of regional deformation,related to movements during indentation tectonics,with emplacement of foliated granites in the western and central areas of the North Patagonian Massif.Between the upper Permian and lower Triassic,evidence indicates emplacement of undeformed granitic bodies in the central part of the North Patagonian Massif.A second pulse of deformation between the middle and upper Triassic is related to the emplacement of the Caita Co granite,the development of mylonitic belts,and the opening of the Los Menucos Basin.During this pulse of deformation,compression direction was from the eastern quadrant. 相似文献
115.
Abdelfattah A. ZALAT 《《地质学报》英文版》2018,92(1):354-366
A detailed analysis of the diatoms from the sedimentary sequence exposed in Abu Qada basin, west central Sinai, was used to determine the palaeoenvironmental changes during the Lower to Middle Miocene. A total of 85 diatom species and varieties belonging to 37 genera were identified from 154 samples collected throughout the stratigraphic succession. The lithological characters of the studied samples varied between sandstone, silty interbeds, sandy shales, shales, and terminated with anhydrite and limestones. These rock units are included in two lithostratigraphic formations (Rudies and Kareem), which are separated by a marked unconformity. The distribution and preservation of fossil diatoms in the sedimentary record are examined with the aim of outlining the temporal and spatial variation in the composition of the diatom assemblages, in order to estimate the changes in depositional environments during the Lower to Middle Miocene. The distributional pattern of the recorded diatom taxa distinguished four diatom eco-zones. The environment of each eco-zone is deduced and a proposed paleobathymetric change and depositional history of the Miocene sediments in the studied area are given. 相似文献
116.
Sarfraz KHAN Umair Bin NISAR Khawar A. AHMED Muhammad WASEEM Waqas AHMED 《《地质学报》英文版》2018,92(4):1544-1557
A structural interpretation of the Ziarat block in the Balochistan region (a part of the Suleiman Fold and Thrust Belt) has been carried out using seismic and seismological data. Seismic data consists of nine 2.5D pre‐stack migrated seismic lines, whereas the seismological data covers the Fault Plane Solution and source parameters. Structural interpretation describes two broad fault sets of fore and back thrusts in the study area that have resulted in the development of pop‐up structures, accountable for the structural traps and seismicity pattern in terms of seismic hazard. Seismic interpretation includes time and depth contour maps of the Dungan Formation and Ranikot group, while seismological interpretation includes Fault Plane Solution, that is correlated with a geological and structural map of the area for the interpretation of the nature of the subsurface faults. Principal stresses are also estimated for the Ranikot group and Dungan Formation. In order to calculate anisotropic elastic properties, the parameters of the rock strength of the formations are first determined from seismic data, along with the dominant stresses (vertical, minimum horizontal, and maximum horizontal). The differential ratio of the maximum and minimum horizontal stresses is obtained to indicate optimal zones for hydraulic fracturing, and to assess the potential for geothermal energy reservoir prospect generation. The stress maps indicate high values towards the deeper part of the horizon, and low towards the shallower part, attributed to the lithological and structural variation in the area. Outcomes of structural interpretation indicate a good correlation of structure and tectonics from both seismological and seismic methods. 相似文献
117.
Intraseasonal oscillation of the southwest monsoon over Sri Lanka and evaluation of its subseasonal forecast skill
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斯里兰卡的雨季发生于5-9月间,主要受西南季风的控制.本文发现该地区的西南季风降水存在很强的次季节变率,主导周期为10-35天.降水的季节内变化与西传的异常气旋有关.进一步,利用S2S比较计划中欧洲中心的数值预报模式(ECMWF)提供的回报试验数据,评估了当今动力模式对斯里兰卡西南季风次季节变化的预报技巧.结果显示,对季风指数的预测技巧超过30天,而对降水指数的预测技巧大约两周,且模式的预报技巧具有明显的年际差异.分析表明,能否正确模拟出大尺度环流对热带对流的响应是影响斯里兰卡降水预测的重要因子. 相似文献
118.
The garnet muscovite granitic pegmatite of Um Solimate, in southern Egypt, represents a promising asset for strategic and economic metals, especially Bi–Ni–Ag–Nb–Ta as well as U and Th. The ore bodies occur as large masses, pockets and/or veins of very coarse-grained pegmatites, which consist mainly of K-feldspar, quartz and albite with subordinate muscovite, garnet, and biotite. Radiometric data revealed that eU- and eTh-contents of the pegmatites reach up to 39 ppm and 82 ppm, respectively. The studied pegmatites are enriched in primary U and Th minerals (uraninite, coffinite, thorianite and uranothorite) as well as Hf-rich zircon and monazite, which give rise to anomalous radioactive zones. Niobium-tantalium-bearing minerals (i.e. ferrocolumbite, microlite and uranopyrochlore), xenotime, barite, galena, fluorite, and apatite are ubiquitous, and, consequently, the studied pegmatites belong tothe Niobium–Yttrium–Fluorine-type (NYF) family. The noble metal mineralization includes argentite (Ag2S), native Ni and Bi as well as bismite and bismoclite. In addition, beryl and tourmaline are observed in pegmatites near the contact with metasediments and ultramafic bodies. The observed compositional variations of Ta/(Ta+Nb) and Mn/(Mn+Fe) ratios in columbite (0.08–0.45 and 0.11–0.57, respectively) and Hf contents in zircon (3.54–6.46 wt%) may reflectan extreme degree of magmatic fractionation leading to formation of the pegmatite orebody. 相似文献
119.
In recent years,landslide susceptibility mapping has substantially improved with advances in machine learning.However,there are still challenges remain in landslide mapping due to the availability of limited inventory data.In this paper,a novel method that improves the performance of machine learning techniques is presented.The proposed method creates synthetic inventory data using Generative Adversarial Networks(GANs)for improving the prediction of landslides.In this research,landslide inventory data of 156 landslide locations were identified in Cameron Highlands,Malaysia,taken from previous projects the authors worked on.Elevation,slope,aspect,plan curvature,profile curvature,total curvature,lithology,land use and land cover(LULC),distance to the road,distance to the river,stream power index(SPI),sediment transport index(STI),terrain roughness index(TRI),topographic wetness index(TWI)and vegetation density are geo-environmental factors considered in this study based on suggestions from previous works on Cameron Highlands.To show the capability of GANs in improving landslide prediction models,this study tests the proposed GAN model with benchmark models namely Artificial Neural Network(ANN),Support Vector Machine(SVM),Decision Trees(DT),Random Forest(RF)and Bagging ensemble models with ANN and SVM models.These models were validated using the area under the receiver operating characteristic curve(AUROC).The DT,RF,SVM,ANN and Bagging ensemble could achieve the AUROC values of(0.90,0.94,0.86,0.69 and 0.82)for the training;and the AUROC of(0.76,0.81,0.85,0.72 and 0.75)for the test,subsequently.When using additional samples,the same models achieved the AUROC values of(0.92,0.94,0.88,0.75 and 0.84)for the training and(0.78,0.82,0.82,0.78 and 0.80)for the test,respectively.Using the additional samples improved the test accuracy of all the models except SVM.As a result,in data-scarce environments,this research showed that utilizing GANs to generate supplementary samples is promising because it can improve the predictive capability of common landslide prediction models. 相似文献
120.
David A.Wood 《地学前缘(英文版)》2021,12(6):444-457
The capability of accurately predicting mineralogical brittleness index(BI)from basic suites of well logs is desir-able as it provides a useful indicator of the fracability of tight formations.Measuring mineralogical components in rocks is expensive and time consuming.However,the basic well log curves are not well correlated with BI so correlation-based,machine-learning methods are not able to derive highly accurate BI predictions using such data.A correlation-free,optimized data-matching algorithm is configured to predict BI on a supervised basis from well log and core data available from two published wells in the Lower Barnett Shale Formation(Texas).This transparent open box(TOB)algorithm matches data records by calculating the sum of squared errors be-tween their variables and selecting the best matches as those with the minimum squared errors.It then applies optimizers to adjust weights applied to individual variable errors to minimize the root mean square error(RMSE)between calculated and predicted(BI).The prediction accuracy achieved by TOB using just five well logs(Gr,pb,Ns,Rs,Dt)to predict BI is dependent on the density of data records sampled.At a sampling density of about one sample per 0.5 ft BI is predicted with RMSE~0.056 and R2~0.790.At a sampling density of about one sample per 0.1 ft BI is predicted with RMSE~0.008 and R2~0.995.Adding a stratigraphic height index as an additional(sixth)input variable method improves BI prediction accuracy to RMSE~0.003 and R2~0.999 for the two wells with only 1 record in 10,000 yielding a BI prediction error of>±0.1.The model has the potential to be applied in an unsupervised basis to predict BI from basic well log data in surrounding wells lacking mineralogical measure-ments but with similar lithofacies and burial histories.The method could also be extended to predict elastic rock properties in and seismic attributes from wells and seismic data to improve the precision of brittleness index and fracability mapping spatially. 相似文献