Electrical conductivity of mantle in the North Central region of Nigeria

Obiora, Daniel N.; Okeke, F. N.; Yumoto, K.

doi:10.1016/j.jafrearsci.2014.10.002

Cited by 4 publications

(4 citation statements)

References 42 publications

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“…Consequently, the electrical conductivity profile of this study showed that the conductivity values increased between 110.0 and 320.0 km depths corresponding to the region of global low velocity seismic zone with high conductivity (Tarits, 1994;Kennett and Engdahl, 1991;Dziewonski and Anderson, 1981). Obiora et al (2015) and Campbell and Schiffmacher (1988) also observed similar increase in conductivity between 150.0 and 350.0 km in East Asia and African sector respectively. This conductivity increase within the low velocity seismic zone is attributed to the presence of partial melting (Thybo, 2006).…”

Section: Discussionsupporting

confidence: 55%

“…This is thus found to be in agreement with global model that showed a steep increase in the conductivity profile from about 300 -700 km. (Abidin et al, 2019;Ugbor et al, 2016;Obiora et al, 2015;Obiekezie and Okeke, 2010;Neal et al, 2000;Campbell et al, 1998;Arora et al, 1995;Campbell and Schiffmacher, 1987;Didwall, 1984). At the maximum penetration depths of 1052.8, 1467.…”

Section: Discussionmentioning

confidence: 99%

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Mantle electrical conductivity determination employing the ionospheric solar quiet day (Sq) currents in the Southern African regions

Ngozi¹,

Francisca²,

Daniel³

et al. 2022

Int. J. Phys. Sci.

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Solar quiet (Sq) daily currents variation obtained in the Hermanus (34.34 o S, 19.22 o E), Tsumeb (19.24 o S, 17.72 o E), Hartebeesthoek (25.68 o S, 28.09 o E) and Maputo (25.97 o S, 32.57 o E), were employed in determining the mantle electrical conductivity depth profile of the Southern African region. The external and internal contributions in the solar quiet field were separated using the spherical harmonic analysis (SHA), after which, the transfer functions were used to compute the electrical conductivity depth profiles of the region. A downward increase was observed in electrical conductivities and deep depth of penetration within the Earth regions. In Hartebeesthoek, Hermanus, Maputo and Tsumeb, the evaluated average electrical conductivity values are 0.028 Sm -1 , 0.039 Sm -1 , 0.057 Sm -1 and 0.0.025 Sm -1 at depths of 76.4 km, 84.1 km,141.0 km and 111.5 km at the respective maximum depths of penetration of 1052.8 km, 1467.0 km, 1160.8 km and 1289.5 km in Hartebeesthoek, Hermanus, Maputo and Tsumeb, the calculated electrical conductivity reached the maximum values of 0.498 Sm -1 , 0.323 Sm -1 , 0.387 Sm -1 and 0.187 Sm -1 respectively. Discontinuities were observed in all the profiles but are more prominent in Tsumeb region near 390.0 -750.0 km, 820.0 -980.0 km and 200.0 -300.0 km. From these results, we are stating that the effects from the deeper 3-D structures (such as gold, copper etc), the hydrated transition zone and effect from the ocean contribute to the greater depth of Sq penetration.

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Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

Mantle electrical conductivity determination employing the ionospheric solar quiet day (Sq) currents in the Southern African regions

Ngozi¹,

Francisca²,

Daniel³

et al. 2022

Int. J. Phys. Sci.

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“…Similarly, Obiora et al (2013) and Obiekezie and Okeke (2010) reported conductivity-depth profiles in West Africa. Furthermore, Ugbor et al (2016) employed Sq daily variations to determine the mantle's conductivitydepth profile in the African geomagnetic equatorial zones, while Abidin et al (2019) determined the mantle's conductivity-depth profile in Malaysia using Sq daily current variations.…”

Section: Introductionmentioning

confidence: 82%

“…Therefore, there is an opportunity to contribute to the existing knowledge in these areas. Building on the work of Obiekezie and Okeke (2010), Obiora et al (2013), Obiora et al (2014), Ugbor et al (2016), andSchiffmacher (1988), who focused on different regions of Africa, we aim to consolidate our understanding of the internal structure, composition, and physical state of the African plate as we integrate the unique features of the upper atmosphere and the Earth's interior.…”

Section: Introductionmentioning

confidence: 99%

Contribution of solar quiet (Sq) daily current variations to the deep earth conductivity within the Southern African Region

Ngozi,

Francisca,

Igwe

2023

Int. J. Phys. Sci.

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This work focuses on determining the source current systems by applying the method of spherical harmonic analysis (SHA) to geomagnetic field data obtained from ground measurements. The objectives are to establish the mantle conductivity-depth profile and to compare the results of the profiles from four stations with other research findings. The study utilizes magnetometer data obtained for the year 2011 from geomagnetic stations located in Hermanus, Maputo, Tsumeb, and Hartebeesthoek within the Southern African region. The Gauss SHA method, along with Matlab software, is employed to separate the internal and external field contributions to solar quiet (Sq) current variations. Subsequently, a transfer function is used to calculate the electrical conductivity-depth profile of the region. The results show that, across all the stations, the highest seasonal Sq current was recorded in the month of June for Hartebeesthoek, Hermanus, and Tsumeb regions. Maputo, however, exhibited an exception with nearly triple peaks in the months of March, June, and December, with the highest occurring during the December solstice. The evaluated maximum values for seasonal Sq current in Hartebeesthoek, Hermanus, Maputo, and Tsumeb are approximately 16.0, 12.5, 12.0, and 14.8 nT, respectively. An equinoxial maximum with a value of 2.1 × 103 A was observed in the seasonal external Sq current in March within the Maputo region, while a solsticial minimum with a value of 0.75 × 103 A occurred in June in the Hartebeesthoek region. The seasonal separated external Sq current system pattern appears to be the same as that of the seasonal Sq current system, indicating that the source of the Sq current system is external to the Earth. The study reveals the greatest depth of Sq current penetration and the highest electrical conductivity values within the Southern African region when compared with other research. Finally, this research contributes to establishing the electrical conductivity of Maputo and Hartebeesthoek regions, where no prior work has been conducted.

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Application of solar quiet day (Sq) current in determining mantle electrical-depth conductivity structure – A review

Okeke

Obiora

2016

Journal of African Earth Sciences

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Electrical conductivity of mantle in the North Central region of Nigeria

Cited by 4 publications

References 42 publications

Mantle electrical conductivity determination employing the ionospheric solar quiet day (Sq) currents in the Southern African regions

Mantle electrical conductivity determination employing the ionospheric solar quiet day (Sq) currents in the Southern African regions

Contribution of solar quiet (Sq) daily current variations to the deep earth conductivity within the Southern African Region

Application of solar quiet day (Sq) current in determining mantle electrical-depth conductivity structure – A review

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