Bulletin of the Mineral Research and Exploration (BMRE)
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Statistical approach by factor and cluster analysis on origin of elements from the Hamit plutonic (Turkey) rock samples
No full textThe Hamit pluton forms part of the Central Anatolian Crystalline Complex. It is located N-NE of Kaman (Kirsehir). It covers an area of about 120 km2. The geochemical contents of 63 rock samples collected from this pluton were analyzed for their origin, homogeneity and relationship with crustal rocks. Their element contents were determined by using X-Ray Fluorescence spectroscopy. The samples were divided into 2 major groups based on their similarities: Group 1 contained 63.5% of the samples and indicated they were formed from melts whose contents might have evolved greatly due to crustal assimilation; while the 36.5% of samples belonged to Group 2, and show minimal evolution of the melt. According to the variation in K/Rb ratio versus SiO2 and the Rb/Zr versus SiO2 the initial melt had experience great evolution due to crustal assimilation. The initial melt is considered to have contained “most” of SiO2, TiO2, Fe2O3, MnO, MgO, CaO, P2O5, Sr, Zn, Cu, Ni, Co, Cr, Ba, Nd, Sc and V that formed the pluton, while “majority” of the Al2O3, Nb, Zr, U, Th, Pb, Ga, Rb, Ce and La are considered to have been derived from crustal contamination, and “almost all” of Na2O, K2O and Y are considered to have originated from crustal assimilation.
https://doi.org/10.19111/bulletinofmre.50207
Geological structures mapping using aeromagnetic prospecting and remote sensing data in the karstic massif of Beni Mellal Atlas, Morocco
No full textThe current study exposes the results of aeromagnetic data interpretation and a combined analysis of 1-A sentinel radar image that cover the study area of Beni Mellal Atlas in order to describe the structural geometry and to understand its tectonic evolution. The map of the reduced to pole of residual magnetic field highlights various magnetic anomalies with high amplitudes that correspond to Jurassic-Cretaceous basaltic formations outcropping synclinal basins of Beni Mellal Atlas. The interpretation of magnetic data using tilt derivative (TDR), horizontal gradient technique coupled to upward continuation and Euler Deconvolution allows us to distinguish the fractures network that is affecting the study area. In order to complete this analysis, the Sentinel-A radar image is processed and filtered using SNAP ESA Sentinel-1 toolbox software to extract lineaments. The final structural map reveals four faults groups oriented respectively NE-SW, ENE-WSW to E-W, N-S and NW-SE Their depths estimated by the application of Euler deconvolution exceed 1500 m.Thoses faults have played a major role in structural evolution of Beni Mellal Atlas.
https://doi.org/10.19111/bulletinofmre.50209
An approach to obtain the structural information from the electrical resistivity well logging curves
No full textIn well logging measurements, the effect of the fluid in the well on the resistivity log curves and the investigation depth/distance for 16 and 64 inches logs were investigated in two-dimensional numerical modeling with the assumption that underground structures are symmetrical. Structural information was obtained via recovering the real resistivity values by using the inversion rather than empirical approaches. Generally, in the case of using the conductive fluid (1 ohm.m\u3c) depending on the ratio of unit thickness (k) with respect to the length of log (l) (i.e. k/l), the insulating formations produce an “M” shaped signs for k/l\u3c1 and appears as the conductive unit that cause fictitious structures in the data. The depth/distance of the research on the other hand causes deviations in the resistivity of structure due to tool length and distance. By the help of the inversion study one of the possible models is obtained. Contribution of this method to such studies is the reveal of compatibility of the resistivity model and data that usually neglected in other approaches.
https://doi.org/10.19111/bulletinofmre.45154
Sedimentological properties and depositional environments of the Holocene sequence in Yenikapı, İstanbul
No full textDuring the salvage excavations in the area of the former Theodosian harbor in Yenikapı-İstanbul several ship wrecks from the Byzantine period, archaeological objects from different periods and a Holocene aged sedimentary sequence have been uncovered. In this study the lithological, lithostratigraphical and facies properties of the Holocene sequence are investigated in detail and its depositional environment is determined. For this purpose along four profiles (S1, S2, S3, S4) 14 different sections of a total thickness of 17.75 m are studied and 100 samples are collected. The grain size distribution of the samples is defined by sieve and sedigraph analysis and mineralogical composition by XRD method. Results of these analyses and facies characteristics of this poorly known Holocene sequence are used for the definition of the depositional environment. Accordingly, the marine sediments are deposited in a near-shore environment, with a natural embayment or estuary transgressively. Terrigenous and anthropogenic material carried by the Lycos River, at the mouth of this natural embayment, resulted in first a regression and then a high-energy fluvial system in the study area.
https://doi.org/10.19111/bulletinofmre.50241
Rare earth elements and yttrium geochemistry of the geothermal fields in the Eastern Black Sea Region (Ordu, Rize, Artvin), NE Turkey
No full textIn this study, behavior and migration processes of rare earth elements (REEs) were determined in the thermal and cold waters of the geothermal fields in the Eastern Black Sea Region.The temperatures of the geothermal waters are between the range of 38 and 60 °C. The water types are Na-Ca-SO4 for Sarmaşık (Ordu) field, Na-Ca-HCO3 for Ikizdere (Rize) field, Na-Ca-CO3-SO4, for Ayder (Rize) field and Na-HCO3-Cl for Savsat (Artvin) field. All geothermal fields are in alkaline geothermal character (pH: 7-9.3) and have very low REE + Y concentrations, slightly significant Ce contens and significantly positive Eu anomalies (except for Ayder geothermal field). REE+Y content, fractionation and positive Eu anomalies of the investigated water are controlled by water/rock ratio, pH and minerals in the host rocks. According to the thermodynamic calculations, it was determined that the mobility of the REEs in geothermal fields were mainly controlled by Ln3+, LnOH2+, LnCl2+, Ln(SO4)2-, LnSO4+, LnHCO32+, Ln(CO3)2- and LnCO3+ complexes.
https://doi.org/10.19111/bulletinofmre.50283
Simulation of a salt dome using 2D linear and nonlinear inverse modeling of residual gravity field data
No full textIn gravity field inversion we usually dealing with underdetermined problems and for obtaining realistic solutions can introduce a depth-weighting function to the inversion algorithm. We employ a linear inversion method for determining the underground density distribution of the gravity causative mass. The validation and accuracy of method is tested on two synthetic gravity anomaly from different models, while the data are noise- free and corrupted with noise. In this paper, We also invert the 2D gravity anomaly produced by a salt dome from the northwest of Iran. The salt domes in the region under investigation are a rich source of Potash. The inverted structure demonstrate on average a depth to top and bottom of 27 m and 65 m, respectively. For comparison, we also have simulated the salt dome using the nonlinear inverse modeling. The results are mostly similar. https://doi.org/10.19111/bulletinofmre.50202
Factors controlling the paleo-sedimentary conditions of Çeltek oil shale, Sorgun-Yozgat/Turkey
No full textThe study field covering an area of about 1000 km2 is located in Sorgun town of the city of Yozgat. In the region Paleozoic, Campanian-Maastrichtian, Eocene, Miocene and Quaternary units are exposed. Among these units, the lower Eocene Çeltek formation hosts coal beds and oil shale. The Eocene epoch is important for organic matter deposition regarding oil and gas productivity and anoxic depositional conditions. In order to examine the paleo-sedimentary conditions of oil shales in the study area and their relation to Total Organic Carbon (TOC) contents and major-trace element contents, a total of 29 samples were collected from two boreholes and one Measured Stratigraphic Section (MSS). Samples have TOC contents varying from 1.97 to 16.17 wt% (average 6.30 wt%). The V/Cr, V/(V+Ni), U/Th, δU and Authigenic Uranium (AU) values of the Çeltek formation oil shales (ÇFOS) reveal that the oil shales have been deposited under variable paleo-environmental conditions. For paleo-salinity the Sr/Ba ratios indicate mostly deposition in a freshwater environment. Chemical Alteration Index (CIA) values and Sr/ Cu ratios indicate that paleo-climate conditions of ÇFOS were dry, hot and occasionally humid. The Fe/ Ti and (Fe+Mn)/Ti ratios reveal hydrothermal activity during sedimentation of oil shales. Zr/Rb ratios of samples are indicative of very weak paleo-hydrodynamics during the deposition of oil shales. Such variable geochemical conditions in the basin resulted in variable paleo-environmental conditions.
https://doi.org/10.19111/bulletinofmre.49470
Statistical assessment of radiation exposure risks of farmers in Odo Oba, Southwestern Nigeria
No full textThe 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.
https://doi.org/10.19111/bulletinofmre.49532
Evaluation of soil geochemistry data of Canca Area (Gümüşhane, Turkey) by means of Inverse Distance Weighting (IDW) and Kriging methods-preliminary findings
No full textThe purpose of this study is to assess soil geochemical data of the Canca alteration area (Gümüşhane- Turkey) using statistical methods and investigate potential gold mineralizations of the area. With this purpose, 288 soil samples were collected and analyzed for gold and associated pathfinder elements. The concentrations ranged (Au and Hg: in μg/kg, others in mg/kg) between 0,68-19,20; 0,02-28,97; 2-314; 7-857; 2,1-394; 4-199,5; 0,59-49,29; 5-89; 0,04-37; 0,52-16,30; 1,25-91,9 for Au, Ag, Cu, Pb, Zn, As, Sb, Bi, Mo, Sn and Hg respectively. According to Sperman’s rho correlation coefficients, although not very strong, correlation was observed between Cu and Au; Zn and Cu; Sb and Pb and As; Mo and Pb and As and Sb; Sn and As; Sb and Mo. The threshold values of the elements were obtained by median+2 the median absolute deviation. The prediction maps of the elements were formed by using the Inverse Distance Weighting and Kriging methods. According to prediction maps; especially in the western part of the study area and also related to tectonic lines, elemental enrichments, (gold and silver) were determined. Therefore, it is suggested to give importance to the west of the area in exploration drilling, geophysics, etc. Since the element prediction maps produced by the Inverse Distance Weighting method has higher resolution in anomaly contrast, it is suggested that maps produced with this method can preferably be used to give an idea at first sight in soil geochemistry studies. DOI: 10.19111/bulletinofmre.43053
Multivariate analysis of log-ratio transformed data and its priority in mining science: Porphyry and polymetallic vein deposits case studies
No full textEach 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.45695