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Reconstruction and appraisal of Akunu–Akoko area iron ore deposits using geological and magnetic approaches

Abstract

Geological mapping and magnetic methods were applied for the exploration of iron ore deposits in the Akunu–Akoko area of Southwestern Nigeria for the purpose of evaluating their geological characteristics and resource potentials. A proton magnetometer measures the vertical, horizontal and total magnetic intensities in gammas. The subsurface geology was interpreted qualitatively and quantitatively. The downward continuations and second vertical derivatives, the small-sized mineralised bodies and shallow features in the study area were mapped. The faults are trending in the following directions: NE–SW, NW–SE, N–S and E–W groups, while the iron ore mineralisation is structurally controlled by two major groups of fault trends, namely, the NE–SW and NW–SE; the N–S and E–W groups are mere occurrences that do not contribute to the structural control of the iron ore mineralisation in Akunu.

The upward continuation has a linear feature similar to the principal orientation of the regional faults, while Locations 2 and 3 have relatively high magnetic susceptibility zones; suspected to be iron ore deposits. The depths to the magnetic sources ranged from 25 m to about 250 m.

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Geophysical investigation of banded iron ore mineralization at Ero, North – Central Nigeria

Abstract

The banded iron ore mineralization at Ero was investigated using aeromagnetic, resistivity and induced polarization (IP) methods with the aim of characterizing the deposit. Analysis of the aeromagnetic data involved the application of reduced-to-equator transformation, derivative filters, analytic signal and source parameter imaging techniques. Computer modelling of some of the identified anomalies was undertaken. The electrical resistivity and IP methods helped in discriminating between the iron ore and the host rock. The results showed that the banded iron formations (BIFs) were characterized by spherical analytic signal anomalies ranging from 0.035 nT/m to 0.06 nT/m within the granite gneiss and magnetic susceptibility of 0.007-0.014 SI. The iron ore had low chargeability (0.1-5.0 msec) and resistivity (1.5 × 102 to 2.5 × 103 Ωm). Structural features trending in the NE-SW, E-W, and NW-SE were identified, suggesting that the area had undergone many episodes of tectonic events. Depth to the BIF varied from the surface up to about 200 m. The chargeability response of the iron bodies suggested an average grade of 20%-40%, making the prospect for economic exploitation attractive.

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Study of magnetic inhomogeneity in β-Cu3Fe4V6O24

Abstract

The temperature dependence of dc magnetization and electron paramagnetic resonance (EPR) spectra of the β-Cu3Fe4V6O24 multicomponent vanadate were investigated. Dc magnetic measurements showed the presence of strong antiferromagnetic interactions (Curie-Weiss temperature, Θ ∼ 80 K) at high temperatures, while zero-field-cooled (ZFC) magnetization revealed a cusp-like maximum in low fields at Tf1 = 4.4 K, which coincides with the splitting of the ZFC and FC curves. Another maximum was registered at Tf2 = 3.0 K. These two temperatures (Tf1 and Tf2) could be regarded as freezing temperatures in the spin glass state of two magnetic sublattices of Fe1 and Fe2 ions. The EPR spectrum of β-Cu3Fe4V6O24 is dominated by a nearly symmetrical, very intense and broad resonance line centered at g eff ∼ 2.0 that could be attributed to iron ions. Below 10 K, an additional EPR spectrum with g 1 = 2.018(1) and g 2 = 2.175(1) appears, as well as a very weak line at geff = 1.99(1). The former spectrum is probably is due to divalent copper ions, and the latter line due to vanadium V4+ complexes. The temperature dependence of EPR parameters (g-factor, linewidth, integrated intensity) was determined in the range of 3–300 K. Two low-temperature maxima in the temperature dependence of the integrated intensity (at 40 and 6 K) were fitted with a function suitable for pairs of exchange-coupled Fe3+ ions. A comparison of dc magnetic susceptibility and EPR integrated intensity indicates the presence of spin clusters, which play an important role in determining the low-temperature magnetic response of β-Cu3Fe4V6O24.

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Geochronology and Palaeomagnetic Records of the Snaigupėlė Section in South Lithuania

. Studies of microtectonics, anisotropy of magnetic susceptibility and paleomagnetism of the Permian Dome de Barrot (France): Paleotectonics and paleosedimentological implications. Tectonophysics 17: 61-72, DOI 10.1016/0040-1951(73)90065-6. Hrouda F, 1979. The strain interpretation of magnetic anisotropy in rocks of the Nizky Jesenik Mountains (Czechoslovakia). Sborník geologických věd UG 16: 27-62. Hrouda F, 2002. The use of the anisotropy of magnetic remanence in the resolution of the anisotropy of magnetic susceptibility into its fer

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An integrated paleomagnetic and magnetic anisotropy study of the Oligocene flysch from the Dukla nappe, Outer Western Carpathians, Poland

References Besse J. & Courtillot V. 2002: Apparent and true polar wander and the geometry of the geomagnetic field over the last 200 Myr. J. Geophys. Res. 107, 6, 1-31. Biró T., Karátson D., Márton E., Józsa S. & Bradák B. 2015: Paleoflow directions from a subaqueous lahar deposit around the Miocene Keserűs Hill lava dome complex (north Hungary) as constrained by photo-statistics and anisotropy of magnetic susceptibility (AMS). J. Volcanol. Geotherm. Res. 302, 141-149. Bordás R. 1990: Aniso - Anisotropy program

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A New Original Conception in Rock Magnetism, Paleomagnetism and Geomagnetism: An Origin of the Reversed Magnetization of Rocks on Earth

Abstract

So far the field-reversal theory has been accepted to account for the reversed remanent magnetization (RM) of rocks on the Earth. Orlickỳ (2014) revealed a frequent occurrence of the antiferromagnetic (AFM) Fe-Ti oxides in the rocks. Now I have renamed these minerals as the Fe-Ti ferrimagnetic-antiferromagnetic chemical phases (Fe- Ti FriM-AFM ChPs). They may have either cubic spinel, or tetragonal spinel symmetry, respectively. They behave as the Fe-Ti polycrystalline materials. These Fe-Ti FriMAFM ChPs are the two sublattice A and B ChPs, with some specific magnetic behaviour. The titanomagnetite (Ti-Mt, Curie temperature, TC = 230 oC; FriM alignment) and the titanomaghemite (Ti-Mgh, Néel temperature, TN = 450 oC; AFM alignment) containing rocks have been identified as the representants of the the Fe-Ti FriM-AFM cubic spinel ChPs. The interactions with the magnetizing field, with the Weis molecular fields (Weiss-Heisenberg forces) have generated the reversally oriented internal field. The reversally oriented spontaneous magnetization has arosen in the rock. This internal field has been identified as the most important phenomenon leading to the production of the reversally oriented magnetization in the Fe-Ti FriM-AFM ChPs containing rocks. The equations expressing the magnetic behaviour of the magnetic susceptibility (κ) of rocks versus temperature have been derived. The Fe-Ti FriM-AFM cubic spinel can undergone the transition in favour of the Fe-Ti FriM-AFM tetragonal spinel in the rocks, due to a change of the thermodynamic conditions in nature. The reversed RM has supposed been inparted from the Fe-Ti FriM-AFM cubic spinel during this alteration-transition processess. Such tetragonal spinel is more stable and it is able to survive in the rocks in nature. The results of laboratory magnetization of the selected groupings of rocks have been presented below. The basic laboratory methods for the detection of the magnetic behaviour of the Fe-Ti FriM-AFM ChPs containing rocks are described as well. The presented results have shown that we do not need to apply the field reversal theory, because I have revealed the realistic mechanism which is able to generate the reversed RM of rocks under a presence of the normal geomagnetic field.

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Influence of Magnetic Particles Concentration in Ferro-Oil on Values of Friction Force and Coefficient of Friction of Slide Journal Bearing

of magnetic particles in the aspect of pressure changes , Tribologia (in press), 2017. [6] Frycz, M., The ferro-oils viscosity depended simultaneously on the temperature and magnetic oil particles concentration η=η (T, ϕ) – part I , Journal of KONES Powertrain and Transport, Vol. 23, No. 2, pp.113-120, 2016. [7] Frycz, M., Anioł, P., Impact of magnetic particles concentration in ferro-oil on its magnetic susceptibility coefficient χ , Journal of KONES Powertrain and Transport, Vol. 21, No. 3, pp. 139-144, 2014. [8] Frycz, M., Czaban, A

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Measurement and Imaging of Planar Electromagnetic Phantoms Based on NMR Imaging Methods

. IEEE Trans. on Magnetics , 40, 2188-2190. Frollo, I., Andris, P., Přibil, J., Juráš, V. (2007). Indirect susceptibility mapping of thin-layer samples using nuclear magnetic resonance imaging. IEEE Trans. on Magnetics , 43 (8), 3363-3367. Bhagwandien, R., Moerland, M., Bakker, C., Beersma, R., Lagendijk, J. (1992). Numerical analysis of the magnetic field for arbitrary magnetic susceptibility distributions in 2D. Magnetic Resonance Imaging , 10 (2), 299-313. Willcott, M. R., Mee, G. L

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Iron-containing phases in fly ashes from different combustion systems

., François, M., Abdelmoula, M., Refait, Ph., Pellissier, C., & Evrard, O. (1999). Characterization of magnetite in silico-aluminous fly ash by SEM, TEM, XRD, magnetic susceptibility, and Mössbauer spectroscopy. Cement. Concr. Res ., 29 , 1705–1711. DOI: 10.1016/S0008-8846(99)00133-7. 7. Javed, A., Szumiata, T., Morley, N. A., & Gibbs, M. R. J. (2010). An investigation of the effect of structural order on magnetostriction and magnetic behaviour of Fe-Ga thin films. Acta Mater ., 58 , 4003–4011. DOI: 10.1016/j.actamat.2010.03.023. 8. Szumiata, T., Górka, B., Brzózka

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Mössbauer and heat capacity studies of ErZnSn2

. Alloy. Compd., 319, 43-49. DOI: 10.1016/S0925-8388(01)00896-9. 11. Łątka, K., Chajec, W., Kmieć, R., & Pacyna, A. W. J. (2001). Magnetic susceptibility and 119Sn Mössbauer spectroscopy studies of RAuSn compounds (R=La, Ce, Pr). J. Magn. Magn. Mater., 224, 241-248. DOI: 10.1016/S0304-8853(01)00035-X. 12. Łątka, K., Kmieć, R., Kruk, R., Pacyna, A. W., Rams, M., Schmidt, T., & Pöttgen, R. (2003). Exotic phase transitions in RERhSn compounds. Nukleonika, 48(S1), S35-S40. 13. Łątka, K., Kmieć, R., Kruk, R., Pacyna, A. W

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