The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area, Sinai, Egypt

Nada, Ayman; Aly, Hanan A. S.

doi:10.1016/j.apradiso.2013.10.003

Cited by 5 publications

(3 citation statements)

References 8 publications

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“…Nevertheless there are daughter product isotopes in the natural decay series which likewise have appropriately long half-lives that it is likely their equilibrium relationship (ratio) to their parent (initial) isotope can be altered by chemical and physical processes in nature (El Afandy 2018). The left over elements (isotopes) have very short half-lives and continuously in radioactive equilibrium with their parents isotopes but there is one exclusion which is the 222Rn with a very short half-life of 0.38x10 days which can escape from rocks due to its distinct feature being a gas (Nada and Aly 2013).…”

Section: Gamma Ray Spectrometry and Radioactive Series Disequilibriummentioning

confidence: 99%

Modification of Radiogenic Heat Production (RHP) Equation due to Radioactive Disequilibrium in Rock Samples from Gamma-Ray Spectrometry

Alabi,

Sedara,

Ajah

et al. 2023

Preprint

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Many factors complicate the estimation of radiogenic heat production (RHP) which may lead to radionuclide concentrations which does not characterize the RHP being produced by rocks. One of this is the Uranium disequilibrium effect. We modified an existing model to minimize this effect. A revised data from gamma-ray spectrometry was used to compute the Beta and Alpha energies (Eβmax) of decay schemes, mass defect (EΔm)of radioelements, total absorbed energy (Eabs) per atom, numerical constants (Ai) and converted to the accepted RHP unit (µWm-3). The modified RHP model (A3) was evaluated and validated using error metrics and radiometric data from seven regions of Nigeria and India. The data was normalized to transform features to be on a similar scale to attain a normal distribution of the data. The modified model (A3) was compared with Birch’s (A1) and Rybach’s (A2) RHP models. All these processes were implemented in Python environment. The RHP constants is several percent higher (6.2% for U; 11.5% for Th) than the values of A1 and A2 RHP models except for Potassium which is higher (74.3%). The A3 RHP model gotten is: A(µWm-3) = ρ(0.103CU + 0.29CTh + 0.061CK). The contributing percentages of the radioelements were in the order of 40K > 238U > 232Th for the Southwest, Southeast and Northcentral regions of Nigeria while the order is 238U > 232Th > 40K for the Southsouth, Northeast and Northwest regions and in order 232Th > 238U > 40K for the Indian region. The A3 model returned a higher R2 value and lower SSE/RMSE/MAE values compared to A1 and A2 models. The R2 values ranged from 42–72% while RMSE ranged from 0.790–1.127. The A3 has the best performance in all metrics for all the regions. The coefficient of determination (R2) for the proportion of variance of the contribution of the radioelements placed K-40 as most dependent variable with a good correlation with the total RHP in the order of use of A1 < A2 < A3. In general A3 return the highest RHP values across all regions. The A3 RHP model gave a higher R2 value and lower RMSE, MAE, SSE values than A1 and A3 RHP models which is an indicator of best performance. The A3 RHP model performed well in all the regions in Nigeria and outside Nigeria. This shows that the A3 RHP model is not geological-formation dependent.

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Section: Gamma Ray Spectrometry and Radioactive Series Disequilibriummentioning

confidence: 99%

Modification of Radiogenic Heat Production (RHP) Equation due to Radioactive Disequilibrium in Rock Samples from Gamma-Ray Spectrometry

Alabi,

Sedara,

Ajah

et al. 2023

Preprint

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“…The radioactive equilibrium of the studied granodiorite, m o nzogranite and altered monzogranite can be determined by calculation as follows; P factor = eU/Ra (El-Galy, 1998;Surour et al, 2001;Raslan and El-Feky, 2012;Nadaa and Aly, 2014). The average P factor values are 2.13, 1.34 and 3.70 for granodiorite, monzogranite and altered monzogranite respectively.…”

Section: Disequilibrium Factormentioning

confidence: 99%

Geology, Geochemistry and Radioactivity of the Monzogranite Rocks, North Wadi Ghadir, South Eastern Desert, Egypt

Khaleal¹,

Kamar²,

El-Sherif³

2017

Nuclear Sciences Scientific Journal

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Wadi Ghadir area show different types of the basement rocks such as; ophiolitic mélange, metabasalt, quartz-diorite, granodiorite and monzogranite. The fresh monzogranite suffered in elsewhere alteration processes and rich in sulphide minerals. The studied monzogranite has peraluminous character, alkaline affinity, emplaced in within plate setting and crystallized under low water vapour pressure (2-3Kb) and temperature (760-800 o C). The propylitic and K-metasomatism are the main alteration types in the studied altered monzogranite, while plagioclase destructed and formed epidote. The identified heavy minerals are mostly pyrite, sphalerite, galena, monazite, hematite and goethite. Mineral chemistry by EPMA analyses exhibit that pyrite mineral is rich in Co and Se and low values of Mn and Cu. The radioactivity increases toward the more acidic rocks, from granodiorite to altered monzogranite. The average eU content indicates that the fresh monzogranite is not uraniferous, while the altered monzogranite is uraniferous.

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“…Leaching, mobility and redistribution of uranium are affected by hydrothermal solutions and/or supergene fluids which cause disequilibrium in the radioactive decay series in the U-bearing rocks. The radioactive equilibrium of the studied metasediment can be determined by the calculation of equilibrium factor (P) which is the ratio of radiometric uranium contents (eU) to the radium content Ra(eU); Pfactor = eU/Ra(eU) (Hussein, 1978;El-Galy, 1998;Surour et al, 2001;Raslan and El-Feky, 2012;Nadaa and Aly, 2014).…”

Section: Radioactive Equilibriummentioning

confidence: 99%

Recent uranium mobilization and radioactivity of metamorphosed sandstones at Sikait area, South Eastern desert of Egypt

Elatta¹,

Hassan²,

El-Farrash³

et al. 2014

J. Geol. Min. Res.

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The metamorphosed sandstones exposures occur in two locations in Wadi Sikait. The exposed rocks in this area are ophiolitic mélange, metamorphosed sandstones, porphrytic granites invaded by postgranite dykes (lamprophyres) and quartz-fluorite veins. The uranium contents measured radiometrically range from 3 to 41.97 ppm, with an average of 12 ppm, while the chemically measured are in the range from 20 to 100 ppm and averaging 50.83 ppm. High uranium contents are mainly attributed to the presence of secondary uranium minerals (uranophane and autonite), accessory minerals (monazite, zircon, allanite and xenotime) and U-bearing minerals (muscovite, biotite, chlorite, iron oxides and clays). P-and D-factors indicate disequilibrium in U-decay due to addition of uranium in these rocks. Since radioactive secular equilibrium of the young age deposits have not yet reached, therefore, the activity ratios (AR) of 230 Th/ 234 U in the studied rocks is very small and ranges from 0.43 to 1.3. Radon exhalation rates of the studied rocks were also measured using ''Sealed Can technique" and indicated the presence of subsurface and surface uranium anomaly which confirms the previous results.

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The effect of uranium migration on radionuclide distributions for soil samples at the El-Gor area, Sinai, Egypt

Cited by 5 publications

References 8 publications

Modification of Radiogenic Heat Production (RHP) Equation due to Radioactive Disequilibrium in Rock Samples from Gamma-Ray Spectrometry

Modification of Radiogenic Heat Production (RHP) Equation due to Radioactive Disequilibrium in Rock Samples from Gamma-Ray Spectrometry

Geology, Geochemistry and Radioactivity of the Monzogranite Rocks, North Wadi Ghadir, South Eastern Desert, Egypt

Recent uranium mobilization and radioactivity of metamorphosed sandstones at Sikait area, South Eastern desert of Egypt

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