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Genetic implications of Th/U, Th/K, and U/K ratios for U mineralizations: A case study from El-Missikat and El-Erediya shear zones, Eastern Desert, Egypt

Geochemical Transactions volume 24, Article number: 3 (2023) Cite this article

Abstract

The current work is an attempt to reveal the possible utilization of the radiometric measurements to build-up a complete genetic scenario for magmatic, hydrothermal, and supergene uranium mineralization. For this purpose, ground gamma-ray survey was performed through the exploratory tunnels dug perpendicular to El-Missikat and El-Erediya shear zones, the Central Eastern Desert of Egypt. Contents of U, Th, and K were measured for the host pink granite (e.g., avg.15.94 U ppm, 35.62 Th ppm, and 6.63% K), alteration zones (brecciation, silicification, greisenization, kaolinization and hematitization) (e.g., avg. 124.01 U ppm, 63.67 Th ppm, and 3.13% K), and mineralized silica veins (e.g., avg. 312.65 U ppm, 92.22 Th ppm, and 2.62% K). All of these data were graphically represented as correlation plots of Th vs. U, Th/U vs. U, Th vs. K, and U/K vs. Th/K. The overall results indicate magmatic, hydrothermal, and supergene sources of El-Missikat and El-Erediya U mineralization. The magma-derived U contents are enclosed mainly in the pink granite that is mostly characterized by normal Th/U (2.5–5) and Th/K ratios (3–5*10–4). The hydrothermal processes through the alteration zones and mineralized silica veins are reflected by the weak correlation of Th with U (e.g. r = 0.13 and − 0.39), the strong negative correlation of Th/U ratio with U (e.g. r = − 0.82), 2.5˃Th/U˃0.1, Th/K˃5*10–4, Th/K < 3*10–4, and the strong positive correlation of U/K with Th/K (e.g. r = 0.91) as well as the occurrence of thorite, columbite, xenotime and hydrothermal zircon (0.5 > Th/U ≤ 0.1). Afterwards, the hydrothermal mineralization underwent some degrees of chemical weathering that resulted in supergene U mineralization whose fingerprints can be traced by the occurrence of secondary U minerals (e.g. kasolite and uranophane), Th/U ratios ≤ 0.1, and the weak correlation between Th/K and U/K (e.g. r = 0.39 and − 0.11).

Introduction

U, Th, and K are considered to be large ion lithophile elements well-known for their radioactivity and heat production as well as the common occurrence, at relative abundances, in granites compared to the other rock types [8, 62]. They have a characteristic geochemical behavior (e.g. the incompatible magmatic fractionation of U and Th in relative to K and the post-magmatic mobilization of U and K compared to Th) under magmatic, hydrothermal, and supergene conditions (e.g [16, 18, 23, 24, 37, 47, 55, 59, 60], making them significant tracers in the geochemical exploration and mapping the hydrothermal and supergene alteration zones (e.g; [1, 13, 20, 26, 27, 36, 46, 48, 49, 51, 58, 64, 66, 67]. Apart from the other geochemical approaches such as fluid inclusions and whole rock geochemistry, the current work tries to build-up a radioelement ratio-based genetic scenario for vein-type uranium mineralizations by measuring Th/U, Th/K, and U/K ratios through host rocks, alteration zones, and U mineralized-veins. For this purpose, polymetallic, vein-type U mineralizations hosted by El-Missikat and El-Erediya pink granites, Eastern Desert of Egypt, were undertaken as a case study. The radioactivity of such localities was first discovered, under supervision of the Egyptian Authority of Nuclear Materials, using airborne gamma-ray survey during a project of uranium exploration between latitudes 25–27ºN, through the Central Eastern Desert of Egypt [7]. This was followed by ground inspection of these anomalous sites, leading to dig a number of exploratory mining tunnels through the northwestern part of El-Missikat pluton and the southern part of El-Erediya pluton [3, 4, 10, 31, 35]).

Geological setting

El-Missikat (26º 28ˋ 33ˋˋand 26º 29ˋ 50ˋˋ N and 33º 22ˋ 6ˋˋ and 33º 23ˋ 6ˋˋE) and El-Erediya pink granites (26º 18ˋ 35ˋˋand 26º 20ˋ 2ˋˋ N & longitudes 33º 28ˋ 10ˋˋ and 33º 29ˋ 43ˋˋE) are exposed as oval-shaped plutons elongated in NNW and NW directions, respectively, through the Central Eastern Desert of Egypt (Fig. 1). These plutons along with the hosted U mineralizations attracted several discussions [3, 4, 4, 5, 9,10,11,12, 30,31,32,33,34,35, 39, 41,42,43, 53, 56, 57, 63]. Accordingly, both El-Missikat and El-Erediya plutons are post-orogenic, peraluminous, medium-to-coarse-grained, younger granitic intrusions composed mainly of perthite (31–50%), plagioclase feldspars (15–20%), and smoky quartz (20–35%), with small amounts of biotite and hornblende (1–3%). Structurally, ENE-WSW and NE-SW trending shear zones cross cut El-Missikat and El-Erediya pink granites, respectively. Moreover, the exploratory mining tunnels through the northwestern part of El-Missikat (Fig. 2) and the southern part of El-Erediya plutons (Fig. 3) revealed that the pink granite is intruded by 1.5 m thick aplite dike at the main adit and suffers brecciation, silicification, greisenization, hematitization, and kaolinization (Figs. 4, 5). Toward the center of shear zone, parallel sets of red to black, lenticular-shaped, siliceous veins invading the pink granite of El-Missikat and El-Erediya areas, were also exposed. They host well-developed fluorite along with U mineralizations, represented mainly by pitchblende, uranophane, autunite, and soddyite, with varied thickness from few centimeters up to 10 m. It is worth to mention that the occurrence of pitchblende is less abundant due to its highly labile behavior under chemical weathering. So, the secondary U minerals, mostly yellowish to greenish in color, are commonly perceived during the field observations (Figs. 6, 7).

Fig. 1
figure 1

Location map of El-Missikat and El-Erediya plutons showing the portal of the mining works

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Fig. 2
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Geological maps of drifts# DI&DIII a and DII b through the northwestern part of El-Missikat pluton (after Abu Dief, 1985), with locations of the studied profiles (red dashed lines)

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Fig. 3
figure 3

Geological maps of drifts# DII&DIII through the southern part of El-Erediya pluton (after El-Tahir, 1985), with locations of the studied profiles (red dashed lines)

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Fig. 4
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Field photographs show the alteration features of El-Missikat pink granite through DI and DII: a brecciation, b silicification, c greisenization, d hematitization, and e kaolinization

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Fig. 5
figure 5

Field photographs show the alteration features of El-Erediya pink granite through DII and DIII: a brecciation, b silicification, c jasperiod vein in silicified granite, and d kaolinization stained by hematitization

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Fig. 6
figure 6

Field photographs show the occurrence of yellowish-greenish yellow secondary U minerals, at DI of El-Missikat shear zone, as fracture infill hosted by the brecciated silica veins a and associated with fluorite (b-look at red arrow), with occasional occurrence through the kaolinized granite (c)

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Fig. 7
figure 7

Field photographs show mineralized silica veins stained by yellowish secondary uranium minerals at DII of El-Erediya shear zone: a brecciated silica vein and b and c jasperoid veins

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Methodology

The distribution of U (ppm), Th (ppm), and 40 K (%) was determined for fresh granite, alteration zones, and radioactive siliceous veins within the exploratory tunnels by handheld gamma-ray spectrometer (RS-230). This device is characterized by BGO ‘‘bismuth germinate oxide’’detector by which the radioelement concentrations are directly measured without the need for calibration resources. The background was measured on the surface for the surrounding fresh granite, out of the exploratory tunnels, at 7.4 ppm U, 26.1 ppm Th, and 6% K. The radioactive measurements were systematically taken through successive profiles, 50 cm/read along each profile, that are perpendicular to shear zone and arranged at 1 m long distance, starting from the main adit until reaching the subsequent drifts (DI and DII at El-Missikat and DII and DIII at El-Erediya). The total count of these measurements for fresh granite, brecciation, greisenization, silicification, kaolinization, hematitization, brecciated and massive silica veins was estimated at 27, 114, 390, 20, 43, 22, 226, and 231 reads. The obtained data set was then undergone statistically processing to study the varied correlations between them and drive the radio-elemental ratios, including Th/U, U/K, and Th/K. On the other hand, the radioactive measurements were coupled by separation of radioactive minerals from some alteration zones and mineralized silica veins at El-Missikat and El-Erediya. For this purpose, representative samples were ground up to − 500 μm and then bromoform-based separation along with handpicking was conducted. The separated mineral fraction was investigated by SEM–EDX. Although the current approach depends mainly on the radiometric measurements, its validity can be substantiated by literature (e.g. Heikal et al. 2022) that compared the radio-elemental ratios of the monzo-syenogranites (the Central Eastern Desert of Egypt)’’ obtained by the ground-gamma ray spectrometer (e.g. avg. 2.53 Th/U ratio) in relative to the data obtained by ICP-MS (e.g. avg. 2.9 Th/U ratio).

Results and discussion

Distribution of radioelements through pink granites

As listed in Table 1, it is clear that the distribution of U, Th, and K through El-Missikat pink granite is greatly similar to El-Erediya counterpart. Comparing with the normal averages in granites (2–8 ppm U, 10–30 ppm Th, and 3.6–4.5% K) [44, 55, 60], El-Missikat (15.94 ppm U, 39.21 ppm Th, and 6.63% K) and El-Erediya pink granite (16.05 ppm U, 35.62 ppm Th, and 7.07% K) can be considered as anomalously radioactive rock suites. The radioactivity is attributed mainly to the anomalous contents of U and Th due to the fact that K has radioactivity (e.g. 12–14 Ur) significantly lower than average granite (20 Ur) (Darnley, 1982). Th/U ratio is estimated at ranges of 1.30–3.5 (avg., 2.59) and 1.01–4.76 (avg., 2.42) for El-Missikat and El-Erediya pink granite, respectively. These values fall through the normal crustal ratio (2.5–5) [6, 21, 22], with some degree of U enrichment indicated by Th/U ratio below 2.5. Th/K ratio generally averages between 5.92*10–4 at El-Missikat and 5.05*10–4 at El-Erediya, and hence it can correspond to the normal crustal value of the unaltered lithologies, estimated at 5–3*10–4 [38, 64]. However, Th enrichment can result in higher Th/K ratios than the normal range (e.g. 8.78 at El-Missikat and 6.37 at El-Erediya).

Table 1 Distribution of U, Th, and K in pink granite through the main adit at El-Missikat and El-Erediya exploratory tunnels
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Distribution of radioelements through alteration zones

Altered granites are characterized by higher radio-measurements of U, Th, and K than that recorded for pink granite (Tables 2, 3). U has a general trend to be decreased from the brecciated granite (avg., 41.53–43.32 ppm at El-Missikat and 116.54–121.4 ppm at El-Erediya), away from the center of shear zone, toward the kaolinized zone (avg., 29.73–29.84 ppm at El-Missikat and 35.79–49.54 ppm at El-Erediya). The latter is generally enriched in U compared to pink granite; however, the low surface area of kaolinite limits the number of adsorption sites for U+6 ions carried by the invading solutions [69]. This can interpret the lower U values of the kaolinized granite compared to the other alteration zones, including brecciation (avg., 41.53–43.32 ppm at El-Missikat and 116.54–121.4 ppm at El-Erediya), silicification (avg., 41.63 ppm at El-Missikat), greisenization (avg., 36.11–41.77 ppm at El-Missikat), and hematitization (avg., 110.84–124.01 ppm at El-Erediya). Also, the maximum U values are measured from greisenization at El-Missikat (71.9–95.6 ppm) and hematitization at El-Erediya (184.6–266.1 ppm), complying with the hypothesis that greisenized and hematitc alterations are among the favorable environments for U accommodation (e.g. [19, 25].

Table 2 Distribution of U, Th, and K for the different alteration zones through drift# DI and D#II at El-Missikat exploratory tunnels
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Table 3 Distribution of U, Th, and K for the different alteration zones through drift# DII and D#III at El-Erediya exploratory tunnels
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Th is measured through the alteration zones of El-Missikat at averages of 58.93–61.72 ppm, 63.67 ppm, 56.4–57.32 ppm, and 54.89–56.21 ppm corresponding to brecciation, silicification, greisenization, and kaolinization, respectively. Comparing with pink granite (avg., 39.21 ppm), there is a noticeable Th enrichment illustrated by Th/U > 1. Depending on the low mobilization behavior of Th in both the hypogene and supergene fluids [54], successive pulses of mineralized solutions are expected. On the other hand, Th values through El-Erediya alteration zones generally exhibit slight depletion (e.g. avg., 33.24–35.46 ppm for hematitization) in relative to pink granite (avg., 35.62 ppm) and the higher U enrichment, resulting in Th/U < 1. For K, its average values remarkably decline (e.g. brecciation ‘‘4.56–6.12%’’, silicification ‘’3.12%, greisenization ‘‘4.46–4.48%’’, and kaolinization ‘‘4.15–4.90%’’) away from that measured for pink granite at El-Missikat (avg., 6.63%), indicating moderately altered K-feldspar was imposed. Except for kaolinization (avg., 4.56%) through DIII at El-Erediya, slight changes of K contents (e.g. avg., 6.01–6.78%) in relative to pink granite (avg., 7.07%) are perceived. All of these changes in K contents are reflected by fluctuations of Th/K ratio above and below the normal value 5*10–4.

Distribution of radioelements through silica veins

Through El-Missikat shear zone (Table 4), U contents in brecciated silica veins (e.g. avg., 88–121 ppm and max., 487–1007.7 ppm) are remarkably higher than the massive veins (e.g. avg., 54.66–82.19 ppm and max., 224.2–676 ppm), indicating other pulses of U-bearing hydrothermal solutions emplaced due to the reactivation of shear zone that in turn caused brecciation of the early-formed silica veins. On the other side, the red silica veins at El-Erediya are characterized by the highest U anomalies (e.g. avg., 183.26–312.65 ppm and max., 536.4–2990.5 ppm), probably due to the co-occurrence of silica and iron oxyhydroxides. The former is considered as a favorable repository for U accommodation that is facilitated by the latter whose task is to adsorb and reduce the dissolved U+6 ions [50].

Table 4 Distribution of U, Th, and K through U-mineralized silica veins at El-Missikat and El-Erediya exploratory tunnels
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Genetic implications using Th/U ratio

U and Th are incompatible trace elements mostly concentrated in granitic magmas where they behave, without fractionation, as tetravalent ions related to each other. This relation is expressed as Th/U ratio that normally varies between 2.5 and 5 [6]. For the felsic magmatism, Th/U ratio is considered as a good indication for the magmatic differentiation degree between peralkaline and peraluminous granitic suites. In peralkaline magma the excess of alkalies in relative to alumina and the high temperature conditions induce high solubility of Th and U-bearing accessory minerals. Hence, the two elements are concentrated with each other and their Th/U ratio remains close to the average crustal ratio ~ 4. On the other side, the peraluminous conditions favor low solubility and fractionation of Th-bearing accessory minerals (e.g. monazite), resulting in an increase of U contents and Th/U ratios < 4 [23]. In all cases, Th and U contents of magmatic origin reveal a strong positive correlation. Comparing with the current study, pink granites of El-Missikat (Fig. 8a) and El-Erediya (Fig. 8b) exhibit moderate and very weak relationship between Th and U at correlation coefficients of 0.5 and 0.04, respectively, indicating U enrichment. Also, U contents exhibit a strong negative correlation with Th/U ratios for El-Missikat (r = − 0.67) (Fig. 8c) and El-Erediya pink granite (r = − 0.82) (Fig. 8d). Further, the calculated Th/U ratios fall through the normal range and below 2.5. Accordingly, magmatic and post-magmatic origin can be presumed for the granite-hosted U mineralization. The post-magmatic source can be either hydrothermal or supergene solutions. The former can be discriminated from the latter using Th/U ratio whose range ‘‘2.5 > Th/U > 0.1’’ is assigned to the hydrothermal uranium mineralizations [17, 40, 68], while values ≤ 0.1 are associated with supergene enrichment [15, 16]. These values, along with the normal ratio, are collectively represented by Th-U variation diagram on which both magmatic and hydrothermal sources are assigned to the anomalous radioactivity of the studied granite at El-Missikat (Fig. 8e) and El-Erediya (Fig. 8f). Another clue can be driven from Th/U ratios measured by Mohammed [52] for zircon crystals separated from El-Missikat ‘‘0.24’’ and El-Erediya granite ‘‘0.30’’. Discussion of these values here according to the recent works (e.g. [45, 61, 70, 71] that categorized zircon into magmatic ‘‘Th/U > 0.5’’, hydrothermal “0.5 > Th/U ≤ 0.1”, and metamorphic variety ‘‘Th/U ≤ 0.1’’, supports the aforementioned hydrothermal origin.

Fig. 8
figure 8

Binary plot of Th and Th/U ratio vs. U for El-Missikat a and c and El-Erediya pink granite b and d, along with variation diagrams (e- El-Missikat and f- El-Erediya) of Th/U ratio showing that the granite-contained U is of both magmatic (2.5–5 Th/U ration) and hydrothermal sources (Th/U<2.5)

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For alteration zones and mineralized silica veins, U enrichment is also reflected by the weak correlation between Th and U (Figs. 910, 11). On Th-U variation diagram, most of the data are concentrated through the hydrothermal field, with an exception for the brecciated silica veins at El-Missikat as well as red silica veins and hematitization at El-Erediya where some samples fall through the field of supergene enrichment (Figs.12, 13, 14). Besides radiometric measurements, the mineral separation for the highly anomalous, mineralized-vein samples revealed the occurrence of some hydrothermally sourced, radioactive minerals, including thorite, betafite, coffinite, and zircon, and some supergene U minerals represented mainly by uranophane and kasolite (Table 5). The aforementioned hydrothermal minerals probably refer to the magmatic source of some pluses of the invading hydrothermal solutions. This claim is suggested according to a number of facts, including the concentration of Th in the residual magmatic fluids, the occurrence of Th-rich minerals (e.g. thorite, and zircon), and the poor liberation behavior of Th from its host rocks by hydrothermal solutions.

Fig. 9
figure 9

Binary plot of Th vs. U through the different alteration zones at El-Missikat drifts# DI a, c, e, and f assigned to brecciation, greisenization, silicification, and kaolinization) and DII (b, d, and g assigned to brecciation, greisenization, and kaolinization) showing weak correlation coefficients as an indication for U-enrichment

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Fig. 10
figure 10

Binary plot of Th vs. U through the different alteration zones at El-Erediya drifts# DII a, c, and e assigned to brecciation, kaolinization, and hematitization) and DIII b, d, and f assigned to the same order) showing weak correlation coefficients as an indication for U-enrichment

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Fig. 11
figure 11

Binary plot of Th vs. U through varied siliceous veins at El-Missikat (a and b brecciated and massive silica veins through drift#DI and c and d brecciated and massive silica veins through drift#DII) and El-Erediya (e &f reddish silica veins through drfits# DII and DIII)

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Fig. 12
figure 12

Th-U variation diagrams of El-Missikat alteration zones at drifts#DI (a, c, e, and f assigned to brecciation, greisenization, silicification, and kaolinization) and DII (b, d, and g assigned to brecciation, greisenization, and kaolinization) discriminate between hydrothermal (2.5 > Th/U > 0.1) and supergene U-mineralization (Th/U ratios ≤ 0.1)

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Fig. 13
figure 13

Th-U variation diagrams of El-Erediya alteration zones at drifts# DII (a, c, and e assigned to brecciation, kaolinization, and hematitization) and DIII (b, d, and f assigned to the same order) discriminate between hydrothermal (2.5 > Th/U > 0.1) and supergene U-mineralization (Th/U ratios ≤ 0.1)

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Fig. 14
figure 14

Th-U variation diagrams of the mineralized silica veins at El-Missikat (a and b brecciated and massive silica veins through drift#DI and c and d brecciated and massive silica veins through drift#DII) and El-Erediya (e and f reddish silica veins through drfits# DII and DIII) discriminate between hydrothermal (2.5 > Th/U > 0.1) and supergene U-mineralization (Th/U ratios ≤ 0.1)

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Table 5 EDX analysis of the separated radioactive minerals from some altered granites and silica veins at El-Missikat and El-Erediya exploratory tunnels
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Genetic implications using Th/K ratio

Th and K are concentrated during the late stages of magmatic differentiation, resulting in a strong positive correlation and 3–5*10−4Th/K ratios for the unaltered rocks [38, 64]. Through this context, Th values were plotted against K contents for the pink granite at El-Missikat and El-Erediya (Fig. 15a and b). This binary plot shows that the two elements are not related to each other (r = 0.14 and 0.15 for El-Missikat and El-Erediya, respectively), implying that the studied granite experienced either Th enrichment or K-metasomatism (potassic alteration). By using Th-K variation diagram constructed from the aforementioned normal ratios, the plotted samples of El-Missikat (Fig. 15c) and El-Erediya (Fig. 15d) pink granite are located through the normal range and the field of Th enrichment in which Th/K ratio > 5*10–4, while no samples are found through the field of K-metasomatism where Th/K<3*10–4. For shear zone, Th-enrichment is considered to be the dominant feature through El-Missikat alteration zones, including brecciation (Fig. 16a and b), greisenization (Fig. 16c and d), silicification (Fig. 16e), and kaolinization (Fig. 16f and g). On the other side, El-Erediya shear zone is characterized by the occurrence of Th enrichment along with normal Th/K ratio through the different alteration features, comprising brecciation (Fig. 17a and b), kaolinization (Fig. 17c and d), and hematitization (Fig. 17e and f). It is worth to mention that the occurrence of normal Th/K ratio through El-Erediya alteration zones likely indicates some pulses of the hydrothermal solutions caused K-metasomatism. Another genetic implication of Th/K ratio is revealed here by its relationship with U/K ratio. It was found that Th/K ratio has a strong positive correlation with U/K ratio through the studied alteration zones (Figs.18, 19) where thorite, zircon, betafite, and coffinite are common. On the other hand, hematitization, red and brecciated silica veins exhibit weak correlations (Fig. 20) and characterized by the abundance of secondary uranium minerals (e.g. uranophane and kasolite). K values are the same for the two ratios, so the strength of correlation indicate the extent to which U and Th mineralizations are associated with each other. In contrast to U, the weak mobilization of Th in supergene solutions causes much lower concentrations [60], and hence there is no chance to correlate with U. On the other side, hydrothermal U mineralization can be associated with hydrothermal Th mineralization (e.g. magmatic-hydrothermal solutions). At this point, it is claimed that Th/K vs. U/K can be used to discriminate between hydrothermal (strong positive correlation) and supergene uranium mineralizations (weak correlation).

Fig. 15
figure 15

Th-K binary plot shows weak correlations of El-Missikat a and El-Erediya pink granite b, along with Th-K variation diagrams reveal normal Th/K ratio (I) (3–5*10–4) and Th-enrichment (III) (Th/K > 5*10–4) of El-Missikat c and El-Erediya pink granite d, without any signs for K-metasomatism (II) (Th/K< 3*10–4)

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Fig. 16
figure 16

Th-K variation diagrams indicate the dominance of Th-enrichment (III) through the alteration zones of El-Missikat exploratory tunnels (a and b brecciation, c and d greisenization, e silicification, f and g kaolinization)

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Fig. 17
figure 17

Th-K variation diagrams show that most measurements through El-Erediya alteration zone (a and b brecciation, c and d kaolinization, e and f hematitization) fall through the normal range (I) and Th-enrichment (III)

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Fig. 18
figure 18

Binary plot of Th/K vs. U/K ratios showing strong positive correlations through the alteration zones of El-Missikat exploratory tunnels (a and b-brecciation, c and d-greisenization, e-silicification, and f and g-kaolinization)

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Fig. 19
figure 19

Binary plot of Th/K vs. U/K ratios showing strong positive correlations through the alteration zones of El-Erediya exploratory tunnels (a and b-brecciation and c&d-kaolinization)

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Fig. 20
figure 20

Binary plot of Th/K vs. U/K ratio showing weak correlations through hematitization (a and b-El-Erediya), red silica veins (c and d-El-Erediya), brecciated silica veins (e and f-El-Missikat), and massive silica veins (g-El-Missikat)

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Conclusion

The detailed study of distribution of U, Th, and K as well as their ratios (Th/U, U/K, and Th/K ratios) through U mineralizations has proven its vital role in providing sufficient information to build-up a genetic scenario about magmatic, hydrothermal, and supergene U deposits. This was manifested by considering the shear zone-related U mineralizations through El-Missikat and El-Erediya exploratory tunnels, the Central Eastern Desert of Egypt, as a case study, where varied alteration zones, primary and secondary U mineralizations are well-exposed. Accordingly, our radiogenic ratios-based genetic scenario can be summarized through three main steps:

  1. (1)

    Tectonic shearing of the pink granite where many pathways become available for the upcoming mineralized solutions.

  2. (2)

    Many successive pulses of U and Th-bearing hydrothermal solutions, some of which are magmatic in origin, invaded the sheared granite and inferred by the weak correlation between U and Th (e.g. r = 0.5 and 0.04 for El-Missikat and El-Erediya granites, respectively) as well as Th and K (e.g. r = 0.14), 2.5 > Th/U > 0.1, Th/K > 5*10–4, the occurrence of thorite, columbite, xenotime and hydrothermal zircon (0.5 > Th/U ≤ 0.1), and the strong positive correlation between Th/K and U/K ratios (e.g. r = 0.74 and 0.80 in greisenized and kaolinized granite at El-Missikat and El-Erediya, respectively).

  3. (3)

    The hydrothermal U mineralization was then affected by the action of chemical weathering, resulting in the occurrence of secondary U minerals, including uranophane, kasolite, and zippeite, in places nearby the shear zone (e.g. brecciated and red silica veins and brecciated granite) where the supergene solutions readily percolate. This is reflected mainly by Th/U ratios ≤ 0.1 and the weak correlation between Th/K and U/K ratios (e.g. r = 0.34 and 0.08 for brecciated and red silica veins, respectively).

Availability of data and materials

All data are represented here.

References

  1. Abdel Hamid AA, El Sundoly HI, Abu Steet AA (2018) Hydrothermal alteration and evolution of Zr-Th-U-REE mineralization in the microgranite of Wadi Ras Abda, North Eastern Desert. Egypt Arabian J Geosci 11(273):1–15

    Google Scholar 

  2. Abu Dief A (1993) The relation between the uranium mineralization and tectonics in some Pan-African granite, west of Safaga, Eastern Desert, Egypt, Ph.D. Thesis. Assuit University.

  3. Abu-Deif A (1985) Geology of Uranium Mineralization in El-Missikat Area, Qena-Safaga Road, Eastern Desert, Egypt, M. Sc. Thesis, Al-Azhar Univ, Cairo: 103 p.

  4. Abu-Deif AA, El-Tahir MA (2008) A new uranium occurrence, Gabal El-Missikat Prospect, Central Eastern Desert. Egypt Earth Sciences 19(1):85–97

    Google Scholar 

  5. Abu-Deif A, Abouelnaga HS, Hassanein HI (2001) Distribution of radioelements and its relation to uranium migration, El Erediya exploratory tunnels, central Eastern Desert. Egypt J King Abdulaziz Univ (Earth Sci) 13:19–40

    Google Scholar 

  6. Allégre CJ, Dupré B, Lewin E (1986) Thorium/Uranium Ration of the Earth. Chem Geol 56:219–227

    Google Scholar 

  7. Ammar A A (1973) Application of aerial radiometry to the study of the geology of Wadi El-Gidami, Eastern Desert (with aeromagnetic application), Ph.D. Thesis, Faculty of Science, Cairo University, 424. P.

  8. Artemieva IM, Thybo H, Jakobsen K, Sørensen NK, Nielsen LSK (2017) Heat production in granitic rocks: Global analysis based on a new data compilation GRANITE2017. Earth Sci Rev 172:1–26

    Google Scholar 

  9. Awad HA, Zakaly HM, Nastavkin AV, El Tohamy AM, El-Taher A (2021) Radioactive mineralizations on granitic rocks and silica veins on shear zone of El-Missikat area, Central Eastern Desert. Egypt Appl Radiation Isotopes 168:109493

    Google Scholar 

  10. Bakhit F S (1978) Geology and radioactive mineralization of Gebal El-Missikat area, Eastern Desert, Egypt, Ph. D. Thesis, Faculty of Science, Ein Shams University, Cairo, 289. P.

  11. Bakhit FS, Assaf HA, DIEF AA (1985) Correlation study on the geology and radioactivity of surface and subsurface working at El Missikat area, Central Eastern Desert. Egypt Mining Geol 35(193):345–354

    Google Scholar 

  12. Bakhit FS, Kassas IAE (1989) Distribution and orientation of radioactive veins in the El Erediya-El Missikat area, Central Eastern Desert Egypt. Int J Remote Sensing 10(3):565–581

    Google Scholar 

  13. Ballouard C, Poujol M, Boulvais P, Mercadier J, Tartèse R, Venneman T, Deloule E, Jolivet M,

  14. Kéré I, Cathelineau M, Cuney M (2017) Magmatic and hydrothermal behavior of uranium in syntectonic leucogranites: The uranium mineralization associated with the Hercynian Guérande granite (Armorican Massif, France). Ore Geol Rev 80:309–331

    Google Scholar 

  15. Bolonin AV, Gradovsky IF (2012) Supergene processes and uranium ore formation in the Ronneburg ore field Germany. GeolOre Deposits 54(2):122–131

    Google Scholar 

  16. Bowden P, Herd D, Kinnaird JA (1995) The significance of Uranium and Thorium concentrations in pegamtitic leucogranites (alaskites), Rössing Mine, Swakopmund. Namibia Communs geol Surv Namibia 10:43–49

    Google Scholar 

  17. Boyle RW (1982) Deposits of Thorium and Uranium and their indicator elements. Dev Econ Geol 16:39–121

    Google Scholar 

  18. Breiter K (2016) Monazite and zircon as major carriers of Th, U, and Y in peraluminous granites: examples from the Bohemian Massif. Mineral Petrol 110:767–785

    Google Scholar 

  19. Burt DM (1989) Compositional and pase relations among rare earth element minerals geochemistry and mineralogy of rare earth elements mineral. Soc Amer 21:260

    Google Scholar 

  20. Chiozzi P, Pasquale V, Verdoya M (2007) Radiometric survey for exploration of hydrothermal alteration in a volcanic area. J Geochem Explor 93:13–20

    Google Scholar 

  21. Condomines M, Morand P, Allégre CJ (1981) 230Th-238U radioactive disequilibria in tholeiites from the FAMOUS zones (Mid-Atlantic Ridge, 36°50’N): Th and Sr isotopic geochemistry. Earth Planet Sci Lett 55:247–256

    Google Scholar 

  22. Condomines M, Morand P, Allégre CJ, Sigvaldason G (1981) 230Th-238U disequilibria in historical lavas from Iceland. Earth Planet Sci Lett 55:393–406

    Google Scholar 

  23. Cuney M (2014) Felsic magmatism and uranium deposits. Bull Soc géol France 185(2):75–92

    Google Scholar 

  24. Darnley A G (1982) Hot Granites: Some General Remarks. In: Maurice, Y.T. (ed), Uranium in Granites. Proceedings of a workshop held in Ottawa, Ontario, Canada. Ministry of Supply and Services Canada, pp. 1–10.

  25. Deng T, Chi G, Zhang X, Li Z, Xu D, Li S, Du P, Shang P, Zou S, Zhou W, Xu K, Yan H, Wen M, Ding Z (2022) Mass Transfer during hematitization and implications for uranium mineralization in the zoujiashan deposit, xiangshan volcanic basin. J Earth Sci 33(2):422–434

    Google Scholar 

  26. Dessouky OK, Ali HH (2018) Using portable gamma-ray spectrometry for testing uranium migration: a case study from the Wadi El Kareim Alkaline Volcanics, Central Eastern Desert Egypt. Acta Geol Sinica 92(6):2214–2232

    Google Scholar 

  27. Dickson BL, Scott KM (1997) Interpretation of aerial gamma ray surveys-adding the geochemical factors. J Aust Geol Geophys 17(2):187–200

    Google Scholar 

  28. Dongarra G (1984) Geochemical behaviour of uranium in the supergene environment. In: Vivo De et al (eds) Uranium geochemistry, mineralogy, geology, exploration and resources. The Institution of Mining and Metallurgy, Dordrecht

    Google Scholar 

  29. EI Tahir M A (1985) Radioactivity and mineralization of granitic rocks of EI-Erediya occurrence and comparison to EI Missikat-Rei EI Garra occurrence, Eastern Desert, Egypt, Ph.D. Thesis, Faculty of Science, AI Azhar University, Cairo Egypt.132p.

  30. El-Kammar AM, El-Hazik N, Mahdi M, Aly N (1997) Geochemistry of accessory minerals associated with radioactive mineralisation in the central Eastern Desert Egypt. J Afr Earth Sci 25(2):237–252

    Google Scholar 

  31. El-Kassas I A (1974) Radioactivity and geology of wadi Atalla area, Eastern Desert of Egypt, A.R.E, Ph. D. Thesis, Faculty of Science, Ein Shams University, Cairo, 502. P.

  32. Elkattan EM, Sadek HS, Rabie SI, Hassanein HI (1995) Ground geophysical study for development and exploration of El Missikat radioactive minerals prospect, central Eastern Desert of Egypt. Nucl Geophys 4(9):363–382

    Google Scholar 

  33. El-Leil IAA, Tolba AS, Omar SA, El-Feky MG, Bakiet MH, Awad HA (2015) Radioactive mineralization of El-Missikat granite; one of most important occurrence, eastern desert Egypt. Int J Innov Sci Eng Technol 2:83–100

    Google Scholar 

  34. El-Sherif AM (2013) Mineralogical characterization of the alteration facies at Gabal El-Missikat Area, Central Eastern Desert. Egypt Nuclear Sciences Scientific Journal 2(1):1–21

    Google Scholar 

  35. El-Tahir M A (1978) Relation between geology and radioactivity of some basement rock to the north of Qena-Safaga Asphaltic Road, Eastern Desert, Egypt, M. Sc. Thesis, Faculty of Science, Al Azhar University, Cairo, 148. P.

  36. Fall M, Baratoux D, Jessell M, Ndiaye PM, Vanderhaeghe O, Moyen JF, Baratoux L, Bonzi WM (2020) The redistribution of thorium, uranium, potassium by magmatic and hydrothermal processes versus surface processes in the Saraya Batholith (Eastern Senegal): Insights from airborne radiometrics data and topographic roughness. J Geochem Explor 219:1–18

    Google Scholar 

  37. Förster HJ (1998) The chemical composition of REE-Y-Th-U-rich accessory minerals in peraluminous granites of the Erzgebirge Fichtelgebirge region, Germany, part I: the monazite-(Ce)-brabantite solid solution series. Am Miner 83:259–272

    Google Scholar 

  38. Galbraith JH, Saunders DF (1983) Rock classification by characteristics of aerial gamma-ray measurements. J Geochem Explor 18:49–73

    Google Scholar 

  39. Hassaan MM, Omar SA, Khalil AE, Shahin TM, El-Naggar IM, Sayyed MI, Hanfi MY (2022) Prognostic exploration of UF-Au-Mo-W younger granites for geochemical pathfinders, genetic affiliations, and tectonic setting in El-Erediya-El-Missikat Province, Eastern Desert. Egypt Minerals 12(5):518

    Google Scholar 

  40. Honghai F, Jinyong C, Shengyun W, Jingyang Z, Dazhao G, Yanning M (2107) Genesis and Uranium Sources of Leucogranite-hosted Uranium Deposits in the Gaudeanmus Area, Central Damara Belt, Namibia: Study of Element and Nd Isotope Geochemistry. ACTA GEOLOGICA SINICA 91 (6), 2126–2137.

  41. Hussein H A M, Sayyah T A (1992) Uranium potential of the younger granites of Egypt (No. IAEA-TECDOC--650).

  42. Hussein H A, Hassan M A, El-Tahir M A, Abou-Deif A (1986) Uranium-bearing siliceous veins in younger granites, Eastern Desert, Egypt (No. IAEA-TECDOC--361).

  43. Ibrahim T M, Cuney M, El Agami N L, Meguid A A A, Zalata A K A (2004) Alteration processes and elements mobility in El Missikat granite, Eastern Desert, Egypt. In Proc. 6th Int. Conf. Geochem., Alexandria Univ., Egypt, VI-B (pp. 465–481).

  44. Killeen PG (1979) Gamma-Ray Spectrometric Methods in Uranium Exploration and Interpretation. Geophysics and Geochemistry in the Search for Metallic Ores, Edited by Hood PJ, Geological Survey of Canada Economic Geology Report 31, 163–230.

  45. Kirkland CL, Smithies RH, Taylor RJM, Evans N, McDonald B (2015) Zircon Th/U ratios in magmatic environs. Lithos 212:397–414

    Google Scholar 

  46. Lentz DR (1991) Radioelement distribution in U, Th, Mo, and rare-earth-element pegamatites, skarns, and veins in a portion of the Grenville Province, Ontario and Quebec. Can J Earth Sci 28(1):1–12

    Google Scholar 

  47. Leroy JL, Turpin L (1988) REE, Th and U behaviour during hydrothermal and supergene processes in a granitic environment. Chem Geol 68:239–251

    Google Scholar 

  48. Maden N, Akaryali E (2015) Gamma ray spectrometry for recognition of hydrothermal alteration zones related to a low sulfidation epithermal gold mineralization (eastern pontides, NE türkiye). J Appl Geophys 122:74–85

    Google Scholar 

  49. Mamouch Y, Attou A, Miftah A, Ouchchen M, Dadi B, Achkouch L, Et-tayea Y, Allaoui A, Boualoul M, Randazzo G, Lanza S, Muzirafuti A (2022) Mapping of Hydrothermal Alteration Zones in the Kelâat M’Gouna Region Using Airborne Gamma-Ray Spectrometry and Remote Sensing Data: Mining Implications (Eastern Anti-Atlas, Morocco). Appl Sci 12(957):1–19

    Google Scholar 

  50. Massey MS, Pacheco JSL, Nelson J, Fendorf S, Maher K (2014) Uranium Incorporation into Amorphous Silica. Environ Sci Technol 48(15):8636–8644

    Google Scholar 

  51. Meisl S, Pöschl W (1982) Radioactive Disequilibrium studies in uranium occurrences of the Odenwald, West Germany. In: Amstutz GC, El Goresy A, Frenzel G, Kluth Moh, G, Wauschkuhn, A, Zimmemmann, RA, (eds) Ore genesis special publication No 2 of the society for geology applied to mineral deposits. Springer-Verlag. Berlin, Heidelberg

    Google Scholar 

  52. Mohammed AA (2001) Morphological and geochemical characteristics of zircon as a guide to uranium origin in El-Missikat and El-Erediya plutons, Central Eastern Desert Egypt. J Facul Educ 26(1):141–155

    Google Scholar 

  53. Nagar MS, Kamal HM, El Monsif AM, Ghazala RA (2020) Potential uranium recovery by percolation leaching from El Missikat mineralized silica vein, Eastern Desert Egypt. Academia J Environ Sci 8(5):071–080

    Google Scholar 

  54. Nash JT (1979) Uranium and thorium in granitic rocks of northeastern Washington and northern Idaho, with comments on uranium resource potential. U.S. Geol Survey Open-File Rep 79–233:1–47

    Google Scholar 

  55. Nishimori R K, Ragland P C, Rogers J J W, Greenberg J K (1977) Uranium Deposits in Granitic Rocks. Energy Research and Development Administration Technical Report-GJBX-13 (77), Grand Junction, Clorado, pp.1–93.

  56. Osman AM, Salman AB, El-Mansi MM, Abdel Ghani IM, Abdallah SM (2005) Mineralogy and uranium distribution in some subsurface sections from El-Missikat and El-Erediya uranium occurrences, Eastern Desert. Egypt Delta J Sci 29:18–38

    Google Scholar 

  57. Rabie SI, Abdel-Meguid AA, Assran AS (1998) Geological and geophysical exploration for uranium mineralization in the El-Erediya prospect Area, Central Eastern Desert. Egypt. Springer, Dordrecht

    Google Scholar 

  58. René M (2020) Alteration of granitoids and uranium mineralization in the Blatná suite of the central bohemian plutonic complex. Czech Republic Minerals 10(821):1–18

    Google Scholar 

  59. Rich RA, Holland HD, Petersen U (1977) Hydrothermal uranium deposits. Elsevier, Amsterdam

    Google Scholar 

  60. Rogers JJW, Adams JAS (1978) Thorium and Uranium. In: Wedepohl KH, Correns CW, Shaw DM, Turekian KK, Zemann J (eds) Handbook of Geochemistry (II-5). Springer-Verlag, Berlin-Heidelberg-New York, pp 798–822

    Google Scholar 

  61. Rubatto D (2017) Zircon: the metamorphic mineral. Rev Mineral Geochem 83:261–295

    Google Scholar 

  62. Scharfenberg L, Regelous A, de Wall H (2019) Radiogenic heat production of Variscan granites from the Western Bohemian Massif, Germany. J Geosci 64:251–269

    Google Scholar 

  63. Shalaby MH, Bishta AZ, Roz ME, El Zalaky MA (2010) Integration of geologic and remote sensing studies for the discovery of uranium mineralization in some granite plutons, Eastern Desert Egypt. J King Abdulaziz Univ Earth Sci 21(1):125

    Google Scholar 

  64. Shives RBK, Charbonneau BW, Ford KL (2000) The detection of potassic alteration by gamma-ray spectrometry-recognition of alteration related to mineralization. Geophysics 65(6):2001–2011

    Google Scholar 

  65. Shives R BK, Charbonneau BE, Ford KL (1997) The detection of potassic alteration by gamma‐ray spectrometry—Recognition of alteration related to mineralization. In Proceedings of Exploration 97: Fourth Decennial Conference on Mineral Exploration, edited by A.G. Gubins, 741–752.

  66. Sobolev IS, Orekhov AN, Bratec T, Rikhvanov LP, Soboleva NP (2018) Variance—correlation analysis in the exploration of hydrothermal (fluidogenous) deposits using surface gamma-ray spectrometry. J Appl Geophys 159:597–604

    Google Scholar 

  67. Uyanık NA, Öncü Z, Uyanık O, Bozcu M (2022) Determination of alteration zones and geological unit limits using natural radioactivity properties of sandikli-şuhut areas. J Appl Geophys. https://doi.org/10.1016/j.jappgeo.2021.104525

    Article  Google Scholar 

  68. Waber N, Schorscher HD, Tj P (1992) Hydrothermal and supergene uranium mineralization at the Osamu Utsumi mine, Poços de Caldas, Minas Gerais, Brazil. J Geochem Explor 45:53–112

    Google Scholar 

  69. Wanggh G, Wang X, Chai X, Liu J, Deng N (2010) Adsorption of uranium (VI) from aqueous solution on calcined and acid-activated kaolin. Appl Clay Sci 47(3–4):448–451

    Google Scholar 

  70. Yakymchuk C, Kirkland CI, Clark C (2018) Th/U ratios in metamorphic zircon. J Metamorphic Geol 36:715–737

    Google Scholar 

  71. Zhai W, Zhang E, Zheng S, Santosh M, Sun X, Niu H, Fu B, Fu Y, Li D, Jiang Y, Liang F, Lin W, Zhao Y, Han S (2022) Hydrothermal zircon: characteristics, genesis and metallogenic implications. Ore Geol Rev 149:1–16

    Google Scholar 

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Acknowledgements

Authors are so grateful and highly appreciate the great collaboration made by the Egyptian Nuclear Materials Authority during field trips and sample collection.

Funding

Open access funding provided by The Science, Technology & Innovation Funding Authority (STDF) in cooperation with The Egyptian Knowledge Bank (EKB). There is no funding for the current work.

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Authors and Affiliations

  1. Department of Geology, Faculty of Science, South Valley University, Qena, Egypt

    Mahmoud Abdel-Hakeem, Mohamed El-Tahir & Hassan Rageh

  2. Nuclear Materials Authority, Maadi, Cairo, Egypt

    Ehab Abu Zeid

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The current topic was suggested by Dr. Abdel-Hakeem and Dr. Tahir; Field works and data collection were carried out by Dr. Abdel-Hakeem, Dr. Tahir, and Dr. Rageh; Data interpretation and manuscript writing were performed by Dr. Ehab and Dr. Abdel-Hakeem.

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Abdel-Hakeem, M., El-Tahir, M., Zeid, E.A. et al. Genetic implications of Th/U, Th/K, and U/K ratios for U mineralizations: A case study from El-Missikat and El-Erediya shear zones, Eastern Desert, Egypt. Geochem Trans 24, 3 (2023). https://doi.org/10.1186/s12932-023-00083-3

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Geochemical Transactions

ISSN: 1467-4866

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