The toxicity risks of being over exposed to ionizing radiation in the environments are of great concern to environmental and health scientists. The distribution of radioactivity concentrations of thorium, uranium and potassium were studied in randomly selected soil samples from ten (10) farm locations in Odo Oba, southwestern Nigeria in order to determine the radiological risks of farmers’ exposure to radionuclides. The mean estimation of thorium and potassium are greater than the global average by factors of 1,5 and 2,7, while that of uranium fall below the global average. The estimation of radioactivity ratios showed a depletion of uranium and enrichment of thorium in the study area. Further analysis on the radioelements (that is, thorium, uranium and potassium) showed that 83% of the estimated radiological risks are above the global average. The multivariate analyses involving Pearson’s correlation, Factor Analysis, Hierarchical Cluster Analysis were also used to explain the correlations among the data sets. It was affirmed from the multivariate analysis that the radiological hazards occur as a result of contributions from the three naturally occurring radionuclides. The values obtained in this study revealed that the sampled locations are contaminated zones for farmers.
Typomorphic features of the quartz of various mineral paragenesis from the gold mineralization in Karakshatau Mountains (West Uzbekistan)
Authors:
Svetlana KOLOSKOVA, Jahongir MOVLANOV
ABSTRACT
As a result of complex studies - geological-structural, morphostructural analytical, mineralogical mapping of quartz formations, detailed geochemical work and analysis of geochemical fields – forecasting prospecting features of gold ore taxon’s: ore zone; ore field; deposit and ore body. They are characterized by groups of criteria: morphostructural, stratigraphic-lithological, structural-tectonic, magmatic, geophysical, metasomatic, mineralogical, geochemical factors and attributes, and a geological-genetic model of the gold-bearing ore-forming system in the collapse zone. Favorable geological and structural conditions for the localization of gold mineralization in the mountains of Karakchatau are associated with the areas of long-term tectonic-magmatic activation in metalliferous sediments of Є-О contrast lithological composition. The coincidence of manifestations of gold mineralization to the blocks formed by transverse faults at the sites where they intersected the Karakchatau crush zone was noted. To the channel-localizing parts inside are blocky and unextended interblock tectonic structures with positions in favorable “structural traps” in their azimuthal curvatures of executed productive types of hydrothermal, sulfidizing quartz. The results of mineralogical mapping of quartz formations along the Karakchatau crush zone (Western Uzbekistan) are considered. Five genetic types of quartz are distinguished. The most productive of them is hydrothermal quartz of types 3 and 4 associated with pyrite,arsenopyrite and gold, which forms vein fields in areas of kinks and expansion of the zone of crushing. Identification of any goods and services that can be used for commercial purposes, including in the geological structure, other regions of Western Uzbekistan.
https://doi.org/10.19111/bulletinofmre.432046
Multivariate analysis of log-ratio transformed data and its priority in mining science: Porphyry and polymetallic vein deposits case studies
Authors:
Farshad DARABI-GOLESTAN, Ardeshir HEZARKHANI
ABSTRACT
Each mineralization style is characterized by typical signature associations between elements due to elemental interactions, therefore the coherence and closure effects problem must be overcome in geochemical processing. The coherence indicates the ratios between two components (rows or columns) remains the same whether they are considered in a subcomposition or in the full composition. The log-ratio transformation (LRT) has recognized as a standard procedure to support subcompositional coherence. The log-transformed data is applicable for geochemical data to unveil such associations, prior to applying the multivariate analysis like correspondence analysis (CA) and principal component analysis (PCA). At the present study, subcompositional coherence is overcome by inverse iso-metric log-ratio transformation for geochemical compositional data at two polymetallic and porphyry deposits. Based on Ilr-transformed data, Ag, Au, As, Pb, Te, Mo and rather S, W, Cu are enriched as polymetallic elements at Glojeh, while Au-Cu-(Mo) compositions indicate a porphyry deposit occurred in Dalli deposit. The ability to handle zero values in the data matrix and determining an elemental eccentricity from the center of each axis based on Euclidean distances are the advantages of CA method, with compression to LRT. Whereas, loading factors which spread in every direction and providing subcompositional coherence are the competitive advantages of PCA based on LRT, for both case studies. Results with these techniques show significant ability to draw an inference in such geochemical data, and in improving the performance of multivariate techniques using LRT.
https://doi.org/10.19111/bulletinofmre.456958
Keywords:
Isometric log-ratio transformation, Subcompositional coherence, Correspondence analysis, Principal component analysis, Geochemical compositional data, Polymetallic and porphyry deposits.
A brief note on the effects of floating standard deviation (non- derivative) and horizontal gradient (derivative) filters
Authors:
Ceyhan Ertan TOKER
ABSTRACT
When processing gravity data, the filters are used in space and frequency environments. The filters allow more selectable parameter estimations than raw data about the structure being examined. Filtering in a broad sense means monitoring the data under the constraints we want. While the filters allow some information to become more noticeable, they allow some information to be lost or become less noticeable from data. In this case, the losses in the data make the interpretation difficult and can cause errors. Derivative and phase filters provide quantitative information about the variation of data in different directions. The display of the change results in a positive or negative manner proportional to derivative sensitivity and phase sharpness, and this may be observed in this data. In the structural boundary analysis, since the sudden changes in the derivative cause oscillations, the boundaries become questionable. Limiting the data neighborhoods with a window by controlling the deviation without using derivative and the filters that allow boundary analysis non-derivative by floating this limitation are used to illuminate the boundary relationships.
https://doi.org/10.19111/bulletinofmre.546153
Keywords:
Gravity, Filter, Standard deviation, Long wavelength, Nonderivatives.