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Geokemija prvin redkih zemelj in njihova vsebnost v sienitih in čarnokitnih kamninah z izbranih lokacij v jugozahodni Nigeriji

Online veröffentlicht: 18 Nov 2022
Volumen & Heft: AHEAD OF PRINT
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Eingereicht: 08 Apr 2022
Akzeptiert: 03 Jun 2022
Zeitschriftendaten
License
Format
Zeitschrift
eISSN
1854-7400
Erstveröffentlichung
30 Mar 2016
Erscheinungsweise
4 Hefte pro Jahr
Sprachen
Englisch
Introduction

Rare earth elements (REE) have attracted much attention in recent years due to their high significance to the entire human population. Their importance in the production of modern technological applications cannot be underestimated, and their global reserve, which is gradually diminishing, has led to an increased demand for these elements. As the global demand for REE increases, the exploration of new REE deposits is essential [1].

Economically, the REE mineralisation and deposits include two separate types: light rare earth element (LREE) deposits and heavy rare earth element (HREE) deposits. Most LREE are produced from carbonatite deposits. Ion-adsorption clay deposits in southern China (referred to as “south China clays”) are currently the world's main source of HREE, they have low REE content, but they are economical because the REE can be easily extracted from them. The second significant HREE sources are alkaline rock-hosted deposits containing HREE and Y as their primary product or co-product. The deposits containing HREE generally tend to be lower grade than the LREE deposits. However, the HREE, based on unit value, can be more valuable and their low-grade deposits may still be economically exploitable [2]. LREE are generally more abundant, and less valuable than the HREE.

Many studies have been carried out in various areas to check for possible REE potential and recent studies have shown possible potential for REE mineralisation in areas that might have been initially overlooked. Because of the need for more exploration and exploitation of these REEs, there is an awakening call for more studies to be carried out in other areas and in rocks that have not been explored [3].

The focus of this study is on determining the abundances of REEs in syenites and charnockitic rocks of selected areas in southwestern Nigeria, in order to determine their mineralisation potential. The study area is underlain by the basement complex of Nigeria. Rahaman [4] reviewed the geology of southwestern Nigeria and recognised six major lithological units, which include (1) the migmatite-gneiss-quartzite complex; (2) the paraschists and metaigneous rocks that consist of pelitic schist, amphibolite, and talcose rocks; (3) metaconglomerates, marbles, and calc-silicate rocks; (4) the charnockitic rocks, (5) the older granites varying in composition from granodiorite to true granites; and (6) potassic syenites and the dolerites. Fifteen different locations around southwestern Nigeria were chosen for the study (Figure 1). The mapped lithological units for these studies are syenites and charnockitic rocks.

Figure 1

Geological map of southwestern Nigeria showing the sampling points. (Modified after the Nigerian Geological Survey Agency [5]).

Materials and methods

Fresh samples of syenites and charnockitic rocks were obtained during systematic field mapping. Petrographic analysis was carried out at the University of Ibadan. Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDS) was used to study possible REE-bearing minerals at the Department of Geology, University of the Free State, South Africa. Ten representative rock samples inclusive of five syenites and five charnockites were analysed for their elemental concentration at the Bureau Veritas Mineral Services, Vancouver, Canada using an inductively coupled plasma-mass spectrometer (ICP-MS).

Results and discussion
Field occurrences and petrographic descriptions

Syenites: The syenites studied were found in the following areas: Awo, Iwo, Okeho, Ayetoro-Oke, and Iwere-Oke. The syenite of Iwo is found as a low-lying and very extensive out-crop; quartzo-feldspathic and pegmatitic veins were observed in the outcrop. It is grey in colour with fine- to medium-grained texture. The Okeho, Ayetoro Oke, and Iwere Oke syenite outcrops were found as low-lying and huge continuous boulders. They are dark green to dark grey in colour with medium- to coarse-grained texture. The petrographic analysis for syenites reveals mineral assemblages of quartz, plagioclase, biotite, olivine, pyroxenes, hornblende, microcline, augites, and opaque minerals (Figure 2a–c).

Figure 2

Photomicrograph of syenites from: (a) Okeho showing B = biotite, P = plagioclase, Ol = Oolivine, My = mymerkite, O = opaque, G = garnet (b) Iwo showing Q = qQuartz, M = microcline, P = plagioclase, Py = pyroxene (c) Kajola showing P = plagioclase, B = biotite, Or = orthoclase, H = hornblende.

Charnockites: The charnockite samples were collected from: Oye, Otun, Ido Osi, Ado, Ikere Ekiti, Akure, and Osuntedo. The charnockitic rocks of Oye occur as low-lying out-crops, boulders, and as road cut in some places. The charnockites in Ado-Ekiti, Ikere, and Akure occur mostly as hills and as large, elongated, and rounded boulders in close association with the porphyritic Older Granite. They are coarse grained with a colour variety ranging from dark green to greenish grey and whitish grey as observed in the sample from Ado-Ekiti. The petrographic analysis revealed mineral assemblages of quartz, plagioclase, orthoclase, biotite, pyroxenes, hornblende, microcline, and opaque minerals (Figure 3a–c).

Figure 3

Photomicrographs of charnockite from a) Akure showing Q = quartz, B = biotite, Opx = orthopyroxene, P = plagioclase, O = opaque; b) Ikere showing Q = quartz, B = biotite, Pl = plagioclase, H = Hornblendeh; and c) Ado showing Q = quartz, B = biotite, P = plagioclase, H = hornblende.

REE minerals

REE-bearing accessory minerals were studied using their chemical compositions as observed via Scanning Electron Microscopy. The observed REE in the charnockite occurred along the rims of zoned apatite (Ca5 (PO4)3 (F, Cl, OH) grain (Figure 4a and b). The zoning might be due to a change in temperature or composition of the fluid from which the crystal crystalised.

Figure 4

(a and b): Back-scattered electron (BSE) image of REE-bearing minerals in the rims of zoned apatite from charnockites; (c and d): BSE image of REE-bearing minerals in syenites.

Apatite was observed to be associated with a mineral suspected to be monazite, which is an REE-concentrating mineral more enriched in LREE. REE minerals in syenites are small and scarce (Figure 4 c and d). Their composition is also very different to the REE minerals in the other samples. The REE-bearing mineral identified in the BSE image of the syenite is suspected to be monazite, on the basis based of its chemical compositions (Table 1).

Chemical composition of the REE minerals in charnockites and syenites.

1 2 3 4 5 6 7 8 9
F 2.41 2.57 2.41
Na2O 1.88 3.6
MgO 0.4 0.52 0.61 0.37 0.86
Al2O3 13.46 13.17 13.3 15.74 1.7 0.49
SiO2 28.39 27.91 29.48 0.75 0.63 0.16 38.14 3.78 4.94
P2O5 5.25 5.85 7 39.4 39.7 40.57 1.87 32.45 25.65
Cl 0.12 0.17 0.12
CaO 18.06 20.12 19.04 57.32 56.94 56.73 12.86 10.9 8.92
Fe2O3 14.22 13.76 12.72 11.85 0.32 12.6
La2O3 5.88 4.91 4.83 4.36 16.99 13.36
Ce2O3 11.01 10.54 8.52 8.66 28.13 25.92
Nd2O3 3.33 3.21 2.62 2.55 5.38 7.25
Total 100 99.99 100 100 100.01 99.99 100
Mineral Monazite Monazite Monazite Apatite Apatite Apatite Monazite

1–7, REE minerals in charnockites, 8–9 REE in syenites.

REE geochemistry

The total REE (∑REE) ranges from 342.54 to 675.15 ppm. The syenites are more enriched in LREE, with values ranging from 325.66 to 648.24 ppm, and Ce, being the most prevalent REE, HREE ranged 19.03–26.91 ppm. The Iwo quartz potassic syenite is characterized by higher ∑REE than the syenites from other areas, with a value of 675.15 ppm. The Kajola and Iwere–Oke syenites have comparable values of 469.17 ppm and 462.69 ppm, respectively, for their ∑REE, while the syenites from Ayetoro–Oke have the lowest ∑REE value of 325.66 ppm (Table 2).

Trace and rare elemental concentration in syenites and charnockites in selected locations in southwestern Nigeria (all values in ppm)

1 2 3 4 5 6 7 8 9 10
Ba 2495 1565 1493 1754 1429 1942 1915 1467 1144 2018
Ga 20.3 19.8 20.1 18.4 20 18.7 19 19.8 19 22.6
Hf 24.5 15.7 11.6 10.2 11.6 5.6 5.6 7.4 12.1 20.6
Nb 31.3 30.4 27.3 22.9 27.9 13 12.9 12.2 24.7 39.3
Rb 384 366.9 263.5 315.7 296 93.4 86 69.8 78.6 105.4
Sr 842 438.1 463.9 455.1 464.1 1062 1028 535.7 465.6 399.3
Th 79.6 60.7 30.8 36.1 45.7 7.6 6 16.6 9 16.4
U 5.9 4.8 4.9 3.9 3.4 1.5 1.1 2.2 1.6 0.8
V 90 60 76 51 64 88 85 59 88 116
W 0.7 1.8 2.2 1.7 1.1 0.9 0.7 <0.5 <0.5 0.8
Zr 1063 597 461 3867 441.6 223.6 220 301.5 531.3 895
Y 28 24.9 26.8 22 32.2 17 15.9 11 26.1 64.1
La 141 111.4 93.6 81.7 106.7 51.4 50.8 70.2 72.1 195.6
Ce 290 212.4 178.5 150.2 200.7 96.1 93.3 109.6 137.1 338.4
Pr 39 24.35 23.08 18.32 25.87 11.97 11.66 11.81 17.45 41.96
Nd 149 81.1 83.6 63.5 93.4 42.9 42.7 37.7 62.6 150.7
Sm 24 12.04 13.54 9.75 15.15 6.77 6.64 4.81 10 23.06
Eu 4.58 2.37 2.57 2.19 2.67 2.12 2.11 2.49 2.86 4.31
Gd 14 7.73 8.96 6.85 10.29 5.1 4.82 3.46 7.94 18.72
Tb 1.44 0.97 1.11 0.83 1.24 0.64 0.6 0.42 1.03 2.39
Dy 6.02 4.72 5.31 4.2 6.02 3.2 3.19 2.05 5.07 12.51
Ho 0.88 0.83 0.94 0.73 1.06 0.6 0.56 0.37 0.93 2.23
Er 2.21 2.11 2.4 1.89 2.85 1.63 1.54 1.08 2.49 5.73
Tm 0.32 0.32 0.33 0.28 0.41 0.22 0.22 0.14 0.33 0.77
Yb 1.95 2.03 2.12 1.82 2.45 1.4 1.35 0.98 1.99 4.64
Lu 0.28 0.32 0.31 0.28 0.36 0.21 0.2 0.14 0.31 0.71
Y 28 24.9 26.8 22 32.2 17 15.9 11 26.1 64.1
ΣLREE 648 443.66 394.89 325.66 444.49 211 207 236 302.11 754.03
ΣHREE 26 19.03 21.48 16.88 24.68 13 12.48 8.64 20.09 47.7
ΣREE 675 462.69 416.37 342.54 469.17 224 220 245 322 802
ΣLREE/ΣHREE 24 23.31 18.38 19.29 18.01 16.26 16.6 27.39 15.1 18.81
ΣREE+Y 703 487.59 443.17 364.54 501.37 241.26 235.59 256.25 348.3 865.83
Eu/Eu* 0.77 0.75 0.71 0.82 0.65 1.1 1.14 1.87 0.98 0.63
Ce/Ce* 0.94 0.98 0.92 0.93 0.92 0.93 0.92 0.92 0.93 0.9
(La/Yb)N 48 37 29.77 30.26 29.36 24.75 25.37 48.29 24.43 28.42
(La/Sm)N 3.66 5.82 4.35 5.27 4.43 4.78 4.81 9.18 4.54 5.34
(Ce/Yb)N 38 27.06 21.78 21.35 21.19 17.76 17.88 28.93 17.82 18.86

Syenites: 1-1wo, 2-Iwere-Ile, 3 - Okeho, 4 - Ayetoro Oke, 5 - Kajola.

Charnockites: 6 - Otun. 7, Ado, 8 – Afao, 9 - Kajola, 10-Akure

The ∑REE of the charnockitic rocks varies with location, ranging from 224.26 ppm in the charnockite of Otun to 801.03 ppm in Akure charnockite. The charnockites are more enriched in LREE with values ranging from 211.28 ppm to 754.03 ppm and relatively depleted in HREE with values ranging from 8.64 ppm to 47.7 ppm. The Akure charnockite is characterised by anomalously high REE contents of 801.03 ppm compared to other charnockites. The syenites and charnockites are characterised by high concentration of LREE and relatively low contents of HREEs with significant LREE/HREE fractionation.

The rocks having more LREE than HREE may be a result of newly formed P-bearing minerals such as apatite or monazite being important carriers of LREE [6, 7]. That the syenites and charnockitic rocks are characterised by high REE concentrations, which is due to the presence of high values of LREE, suggests REE-concentrating minerals (especially monazite, which contains LREE), which indicates that their original magma had crustal input [8].

The (La/Yb)N values ranged from 29.36 to 48.75 for the syenites and from 24.43 to 48.29 for the charnockites; the (La/Sm)N values in syenites is 4.35 : 5.82; and 4.54 : 9.18 in the charnockites. The (Ce/Yb)N ranges from 21.19 to 38.49 for the syenites, and from 17.76 to 28.93 for the charnockites. The high values of the normalised ratios of La to Yb, La to Sm, and Ce to Yb in the different rock types are evidence of a high degree of fractionation, which shows that the REE patterns are LREE enriched.

According to Ukaegbu and Ekwueme [9], the La/Yb, Ce/Yb, and La/Sm values are normally higher in residual products than in primary melts. Hence, (La/Yb)N values higher than 5 are an indication of magmatic differentiation [10]. This implies that even though the magma might have originated from a mixed source, differentiation was important in the formation of these rocks [8].

The syenites showed negative Eu anomalies of 0.65–0.82, suggesting that a large amount of plagioclase was removed from felsic magma during fractional crystallisation. It could also be due to the presence of pyroxenes in them, as pyroxene-rich cumulates acquire a negative Eu anomaly [11]. The charnockitic rocks showed both a negative and a positive Eu anomaly of 0.63–1.87, indicating accumulation of plagioclase during the fractionation of magma for the later (Figure 5). According to Weill and Drake [12], magma crystallising stable plagioclase has most of the Eu being incorporated into the plagioclase mineral leading to a higher concentration of Eu in the mineral relative to other rare earth elements in the magma.

Figure 5

a) Plots of Zr/Y vs Th/Yb for charnockites of the study areas showing three sampling points (after Ross and Bédard [14]; b) Plots of Zr/Y vs Th/Yb for syenites of the study area (after Ross and Bédard [14]); c) Chondrite normalised REE distribution pattern for the syenites (after Boynton [13]); d) Chondrite normalised REE distribution pattern for the charnockites (after Boynton [13]).

The Ce anomaly ranges from 0.92 to 0.98 in the syenites, and from 0.90 to 0.93 in the charnockitic rocks. Ce anomalies reflect the oxygen fugacity in the environment of formation, [13]. According to Boynton [13], when there is no large negative Ce anomaly, it indicates formation under reducing conditions; a large negative Ce anomaly indicates formation under oxidising conditions.

REE mineralisation potential in the syenites and charnockites

In order to determine the mineralisation potential of the syenites and charnockites, the REE-bearing minerals in the rocks were searched for, the mineral apatite and monazite were observed, and a comparative study was carried out comparing between the syenites of this present study with related rocks, which includes the following: the nepheline syenites of the Gboko area, with ∑REE = 130.26 ppm; quartz syenites of the Prakasam alkaline province of India ∑REE = 1685.3 ppm; the quartz syenites from the Nigerian younger granites province ∑REE =1084.6 ppm; and the syenites of Capituva Massif, Brazil ∑REE = 453.28 ppm in order to determine the abundance of ∑REE in the study area syenites relative to those of other areas, (Table 3).

Comparison of the REE concentration in the syenites of the study area with other related rock types (all values in ppm).

1 2 3 4 5 6
REE RANGE AVERAGE AVERAGE Mean RANGE AVERAGE
La 81.72–111.4 257 93.36 42.07 5082–94810 449.5
Ce 150.2–290.2 450 214.36 60.57 7021–90630 798
Pr 18.32–39.02 N/A N/A 5.01 510–5835 75.5
Nd 63.5–149.2 304 105.51 13.04 1592–16418 43.5
Sm 9.75–24.25 66.5 16.72 1.18 110–1147 265.5
Eu 2.19–2.67 7.1 3.69 0.36 22.8–236.5 39
Gd 7.73–10.29 54.8 9.43 1.9 53–513 1.9
Tb 0.83–1.44 6 N/A 0.28 26–52 26
Dy 4.2–6.02 N/A 5.2 1.77 29–338 2.9
Ho 0.73–1.06 N/A 0.98 0.47 23–40 12.5
Er 1.89–2.85 N/A 2.31 1.56 36–395 2.35
Tm 0.28–0.41 N/A N/A 0.15 6–7 5.95
Yb 1.82–2.45 14.4 1.51 1.61 3–52 0.85
Lu 0.28–0.36 2.55 0.21 0.29 0.5–10 0.8
ΣLREE 325.66–648.24 1084.6 433.64 122.23 N/A 1655.4
ΣHREE 16.88–26.91 77.75 19.64 8.03 N/A 29.89
REE 342.54–674.85 1162.35 453.28 130.26 14458–199154 1685.3
ΣLREE/ΣHREE 18.01–24.11 13.95 22.07 15.22 N/A 55.38

1. Syenites of the study areas

2. Syenites of Nigeria Mesozoic granites [15]

3. Syenites of Minias Grais, Brazil [16]

4. Nepheline syenites of Gboko area, Nigeria [17]

5. Carbonatites from Wu dyke, Bayan Obo, North China [18]

6. Quartz syenites of Prakasam alkaline province, India [19]

Charnockitic rocks of the study area were compared with related rock types to determine their ∑REE abundance relative to those of the related rock types. The comparison was done with Charnockites/enderbites of the Obudu Plateau; Garnet-charnockitic gneiss of Congo; charnockites from Kogi, Nigeria; charnockite gneiss from Norway; and charnockites from Pallavaram, Madras city, India (Table 4). The abundance of REE in the syenites and charnockites, when compared to concentrations from regions where REE has been studied and shown to be substantially enriched, suggests that the syenites are fairly enriched, while the charnockites are moderately enriched.

Comparison of the REE concentration in the charnockites of the study area with other related rock types (all values in ppm).

1 2 3 4 5 6
REE RANGE RANGE AVERAGE AVERAGE AVERAGE RANGE
La 50.8–195.6 40.9–147 280.38 136 80.5 20.7–81.7
Ce 93.3–338.4 85.3–287 26.24 301 182.5 28.0–159.0
Pr 11.66–41.96 10.4–31.9 85.5 35.3 N/A N/A
Nd 37.7–150.7 46.9–123 13.62 146 95.5 6.9–66.0
Sm 4.81–23.06 9.7–20.3 4.33 26 20 0.76–15.9
Eu 2.11–4.31 2.35–3.85 12.55 5.8 2.5 1.23–3.17
Gd 3.46–18.72 8.2–15.1 1.95 17.7 18.5 6.0–19.4
Tb 0.42–2.39 1.2–1.8 12.28 2.4 2.95 0.08–0.78
Dy 2.05–12.51 5.9–9.2 2.41 12.6 N/A N/A
Ho 0.37–2.23 1.1–1.6 6.65 2.2 N/A N/A
Er 1.08–5.73 3.1–4.2 0.97 5.7 N/A N/A
Tm 0.22–0.77 0.43–0.54 6.47 0.75 1.445 0.03–2.25
Yb 0.98–4.64 2.6–3.2 0.95 4.2 8.2 0.27–13.8
Lu 0.14–0.71 0.37–0.51 30 0.63 1.13 0.21–1.91
ΣLREE 211.26–754.03 196.7–611 422 650.1 381 57.59–325.77
ΣHREE 8.64–47.7 25.9–36.3 61.7 46.18 32.23 6.59–38.14
ΣREE 219.69–801.73 220.02–647.96 484 696.28 413.23 64.18–363.91

N/A - Not Available

1. Charnockite of the study area

2. Charnockites of Obudu Plateau [20]

3. Garnet-charnockitic gneiss of Congo, South Cameroon [21]

4. Charnockites from Kogi area, Nigeria [22]

5. Charnockites gneiss from South Norway [23]

6. Charnockites from Pallavaram, Madras City, India [24]

Further comparison was done for both the syenites and the charnockitic rocks with carbonatites from Wu dyke, Bayan Obo, North China, an area where REE is mined. The REE concentration in the rocks of the study areas had very low ∑REE relative to the very high REE contents of this rock and are therefore not be economically viable.

Conclusion

The SEM studies of discrete phases of the charnockites revealed the possible presence of REE-bearing minerals, apatite, and monazite, while studies of syenites revealed a possible presence of monazite. The abundance of REEs in the syenites and charnockites, when compared to concentrations from regions where REEs have been studied and shown to be substantially enriched, suggests that the syenites are fairly enriched, while the charnockites are moderately enriched.

Figure 1

Geological map of southwestern Nigeria showing the sampling points. (Modified after the Nigerian Geological Survey Agency [5]).
Geological map of southwestern Nigeria showing the sampling points. (Modified after the Nigerian Geological Survey Agency [5]).

Figure 2

Photomicrograph of syenites from: (a) Okeho showing B = biotite, P = plagioclase, Ol = Oolivine, My = mymerkite, O = opaque, G = garnet (b) Iwo showing Q = qQuartz, M = microcline, P = plagioclase, Py = pyroxene (c) Kajola showing P = plagioclase, B = biotite, Or = orthoclase, H = hornblende.
Photomicrograph of syenites from: (a) Okeho showing B = biotite, P = plagioclase, Ol = Oolivine, My = mymerkite, O = opaque, G = garnet (b) Iwo showing Q = qQuartz, M = microcline, P = plagioclase, Py = pyroxene (c) Kajola showing P = plagioclase, B = biotite, Or = orthoclase, H = hornblende.

Figure 3

Photomicrographs of charnockite from a) Akure showing Q = quartz, B = biotite, Opx = orthopyroxene, P = plagioclase, O = opaque; b) Ikere showing Q = quartz, B = biotite, Pl = plagioclase, H = Hornblendeh; and c) Ado showing Q = quartz, B = biotite, P = plagioclase, H = hornblende.
Photomicrographs of charnockite from a) Akure showing Q = quartz, B = biotite, Opx = orthopyroxene, P = plagioclase, O = opaque; b) Ikere showing Q = quartz, B = biotite, Pl = plagioclase, H = Hornblendeh; and c) Ado showing Q = quartz, B = biotite, P = plagioclase, H = hornblende.

Figure 4

(a and b): Back-scattered electron (BSE) image of REE-bearing minerals in the rims of zoned apatite from charnockites; (c and d): BSE image of REE-bearing minerals in syenites.
(a and b): Back-scattered electron (BSE) image of REE-bearing minerals in the rims of zoned apatite from charnockites; (c and d): BSE image of REE-bearing minerals in syenites.

Figure 5

a) Plots of Zr/Y vs Th/Yb for charnockites of the study areas showing three sampling points (after Ross and Bédard [14]; b) Plots of Zr/Y vs Th/Yb for syenites of the study area (after Ross and Bédard [14]); c) Chondrite normalised REE distribution pattern for the syenites (after Boynton [13]); d) Chondrite normalised REE distribution pattern for the charnockites (after Boynton [13]).
a) Plots of Zr/Y vs Th/Yb for charnockites of the study areas showing three sampling points (after Ross and Bédard [14]; b) Plots of Zr/Y vs Th/Yb for syenites of the study area (after Ross and Bédard [14]); c) Chondrite normalised REE distribution pattern for the syenites (after Boynton [13]); d) Chondrite normalised REE distribution pattern for the charnockites (after Boynton [13]).

Chemical composition of the REE minerals in charnockites and syenites.

1 2 3 4 5 6 7 8 9
F 2.41 2.57 2.41
Na2O 1.88 3.6
MgO 0.4 0.52 0.61 0.37 0.86
Al2O3 13.46 13.17 13.3 15.74 1.7 0.49
SiO2 28.39 27.91 29.48 0.75 0.63 0.16 38.14 3.78 4.94
P2O5 5.25 5.85 7 39.4 39.7 40.57 1.87 32.45 25.65
Cl 0.12 0.17 0.12
CaO 18.06 20.12 19.04 57.32 56.94 56.73 12.86 10.9 8.92
Fe2O3 14.22 13.76 12.72 11.85 0.32 12.6
La2O3 5.88 4.91 4.83 4.36 16.99 13.36
Ce2O3 11.01 10.54 8.52 8.66 28.13 25.92
Nd2O3 3.33 3.21 2.62 2.55 5.38 7.25
Total 100 99.99 100 100 100.01 99.99 100
Mineral Monazite Monazite Monazite Apatite Apatite Apatite Monazite

Comparison of the REE concentration in the syenites of the study area with other related rock types (all values in ppm).

1 2 3 4 5 6
REE RANGE AVERAGE AVERAGE Mean RANGE AVERAGE
La 81.72–111.4 257 93.36 42.07 5082–94810 449.5
Ce 150.2–290.2 450 214.36 60.57 7021–90630 798
Pr 18.32–39.02 N/A N/A 5.01 510–5835 75.5
Nd 63.5–149.2 304 105.51 13.04 1592–16418 43.5
Sm 9.75–24.25 66.5 16.72 1.18 110–1147 265.5
Eu 2.19–2.67 7.1 3.69 0.36 22.8–236.5 39
Gd 7.73–10.29 54.8 9.43 1.9 53–513 1.9
Tb 0.83–1.44 6 N/A 0.28 26–52 26
Dy 4.2–6.02 N/A 5.2 1.77 29–338 2.9
Ho 0.73–1.06 N/A 0.98 0.47 23–40 12.5
Er 1.89–2.85 N/A 2.31 1.56 36–395 2.35
Tm 0.28–0.41 N/A N/A 0.15 6–7 5.95
Yb 1.82–2.45 14.4 1.51 1.61 3–52 0.85
Lu 0.28–0.36 2.55 0.21 0.29 0.5–10 0.8
ΣLREE 325.66–648.24 1084.6 433.64 122.23 N/A 1655.4
ΣHREE 16.88–26.91 77.75 19.64 8.03 N/A 29.89
REE 342.54–674.85 1162.35 453.28 130.26 14458–199154 1685.3
ΣLREE/ΣHREE 18.01–24.11 13.95 22.07 15.22 N/A 55.38

Comparison of the REE concentration in the charnockites of the study area with other related rock types (all values in ppm).

1 2 3 4 5 6
REE RANGE RANGE AVERAGE AVERAGE AVERAGE RANGE
La 50.8–195.6 40.9–147 280.38 136 80.5 20.7–81.7
Ce 93.3–338.4 85.3–287 26.24 301 182.5 28.0–159.0
Pr 11.66–41.96 10.4–31.9 85.5 35.3 N/A N/A
Nd 37.7–150.7 46.9–123 13.62 146 95.5 6.9–66.0
Sm 4.81–23.06 9.7–20.3 4.33 26 20 0.76–15.9
Eu 2.11–4.31 2.35–3.85 12.55 5.8 2.5 1.23–3.17
Gd 3.46–18.72 8.2–15.1 1.95 17.7 18.5 6.0–19.4
Tb 0.42–2.39 1.2–1.8 12.28 2.4 2.95 0.08–0.78
Dy 2.05–12.51 5.9–9.2 2.41 12.6 N/A N/A
Ho 0.37–2.23 1.1–1.6 6.65 2.2 N/A N/A
Er 1.08–5.73 3.1–4.2 0.97 5.7 N/A N/A
Tm 0.22–0.77 0.43–0.54 6.47 0.75 1.445 0.03–2.25
Yb 0.98–4.64 2.6–3.2 0.95 4.2 8.2 0.27–13.8
Lu 0.14–0.71 0.37–0.51 30 0.63 1.13 0.21–1.91
ΣLREE 211.26–754.03 196.7–611 422 650.1 381 57.59–325.77
ΣHREE 8.64–47.7 25.9–36.3 61.7 46.18 32.23 6.59–38.14
ΣREE 219.69–801.73 220.02–647.96 484 696.28 413.23 64.18–363.91

Trace and rare elemental concentration in syenites and charnockites in selected locations in southwestern Nigeria (all values in ppm)

1 2 3 4 5 6 7 8 9 10
Ba 2495 1565 1493 1754 1429 1942 1915 1467 1144 2018
Ga 20.3 19.8 20.1 18.4 20 18.7 19 19.8 19 22.6
Hf 24.5 15.7 11.6 10.2 11.6 5.6 5.6 7.4 12.1 20.6
Nb 31.3 30.4 27.3 22.9 27.9 13 12.9 12.2 24.7 39.3
Rb 384 366.9 263.5 315.7 296 93.4 86 69.8 78.6 105.4
Sr 842 438.1 463.9 455.1 464.1 1062 1028 535.7 465.6 399.3
Th 79.6 60.7 30.8 36.1 45.7 7.6 6 16.6 9 16.4
U 5.9 4.8 4.9 3.9 3.4 1.5 1.1 2.2 1.6 0.8
V 90 60 76 51 64 88 85 59 88 116
W 0.7 1.8 2.2 1.7 1.1 0.9 0.7 <0.5 <0.5 0.8
Zr 1063 597 461 3867 441.6 223.6 220 301.5 531.3 895
Y 28 24.9 26.8 22 32.2 17 15.9 11 26.1 64.1
La 141 111.4 93.6 81.7 106.7 51.4 50.8 70.2 72.1 195.6
Ce 290 212.4 178.5 150.2 200.7 96.1 93.3 109.6 137.1 338.4
Pr 39 24.35 23.08 18.32 25.87 11.97 11.66 11.81 17.45 41.96
Nd 149 81.1 83.6 63.5 93.4 42.9 42.7 37.7 62.6 150.7
Sm 24 12.04 13.54 9.75 15.15 6.77 6.64 4.81 10 23.06
Eu 4.58 2.37 2.57 2.19 2.67 2.12 2.11 2.49 2.86 4.31
Gd 14 7.73 8.96 6.85 10.29 5.1 4.82 3.46 7.94 18.72
Tb 1.44 0.97 1.11 0.83 1.24 0.64 0.6 0.42 1.03 2.39
Dy 6.02 4.72 5.31 4.2 6.02 3.2 3.19 2.05 5.07 12.51
Ho 0.88 0.83 0.94 0.73 1.06 0.6 0.56 0.37 0.93 2.23
Er 2.21 2.11 2.4 1.89 2.85 1.63 1.54 1.08 2.49 5.73
Tm 0.32 0.32 0.33 0.28 0.41 0.22 0.22 0.14 0.33 0.77
Yb 1.95 2.03 2.12 1.82 2.45 1.4 1.35 0.98 1.99 4.64
Lu 0.28 0.32 0.31 0.28 0.36 0.21 0.2 0.14 0.31 0.71
Y 28 24.9 26.8 22 32.2 17 15.9 11 26.1 64.1
ΣLREE 648 443.66 394.89 325.66 444.49 211 207 236 302.11 754.03
ΣHREE 26 19.03 21.48 16.88 24.68 13 12.48 8.64 20.09 47.7
ΣREE 675 462.69 416.37 342.54 469.17 224 220 245 322 802
ΣLREE/ΣHREE 24 23.31 18.38 19.29 18.01 16.26 16.6 27.39 15.1 18.81
ΣREE+Y 703 487.59 443.17 364.54 501.37 241.26 235.59 256.25 348.3 865.83
Eu/Eu* 0.77 0.75 0.71 0.82 0.65 1.1 1.14 1.87 0.98 0.63
Ce/Ce* 0.94 0.98 0.92 0.93 0.92 0.93 0.92 0.92 0.93 0.9
(La/Yb)N 48 37 29.77 30.26 29.36 24.75 25.37 48.29 24.43 28.42
(La/Sm)N 3.66 5.82 4.35 5.27 4.43 4.78 4.81 9.18 4.54 5.34
(Ce/Yb)N 38 27.06 21.78 21.35 21.19 17.76 17.88 28.93 17.82 18.86

Long, K., Gosen, B., Foley, N., Cordier, D. (2010): The principal rare Earth Elements Deposits of the United States: A summary of domestic deposits and a global perspective. U.S. Geological Survey Scientific Investigations Report 2010–5220, 96 p. LongK. GosenB. FoleyN. CordierD. 2010 The principal rare Earth Elements Deposits of the United States: A summary of domestic deposits and a global perspective U.S. Geological Survey Scientific Investigations Report 2010–5220 96 p. 10.3133/sir20105220 Search in Google Scholar

Dostal, J. (2017): Rare earth element deposits of alkaline igneous rocks. Resources, 6(34), pp. 1–2, DOI:10.3390/resources6030034. DostalJ. 2017 Rare earth element deposits of alkaline igneous rocks Resources 6 34 1 2 10.3390/resources6030034 DOI öffnenSearch in Google Scholar

Omotunde, V.B., Olatunji, A.S., Abdus-Salam, M.O. (2020): Rare earth elements assessment in the granitoids of part of Southwestern Nigeria. European Journal of Environment and Earth Sciences, 1(5), pp. 1–10. OmotundeV.B. OlatunjiA.S. Abdus-SalamM.O. 2020 Rare earth elements assessment in the granitoids of part of Southwestern Nigeria European Journal of Environment and Earth Sciences 1 5 1 10 10.24018/ejgeo.2020.1.5.79 Search in Google Scholar

Rahaman, M.A. (1976): Review of the Basement Geology of Southwestern Nigeria. In: Geology of Nigeria, Kogbe, C.A. (ed.). Elizabethan Publ. Co.: Lagos, pp. 41–48. RahamanM.A. 1976 Review of the Basement Geology of Southwestern Nigeria In: Geology of Nigeria KogbeC.A. (ed.). Elizabethan Publ. Co. Lagos 41 48 Search in Google Scholar

Nigerian Geological Survey Agency (2004): Geological map of Nigeria, scale 1:2,000,000. Geological Survey of Nigeria, Abuja. Nigerian Geological Survey Agency 2004 Geological map of Nigeria, scale 1:2,000,000 Geological Survey of Nigeria Abuja Search in Google Scholar

Nyakairu, G.W.A., Koeberl, C. (2001): Mineralogical and chemical composition and distribution of rare earth elements in clay-rich sediments from Central Uganda. Geochemistry Journal, 35, pp. 13–28. NyakairuG.W.A. KoeberlC. 2001 Mineralogical and chemical composition and distribution of rare earth elements in clay-rich sediments from Central Uganda Geochemistry Journal 35 13 28 10.2343/geochemj.35.13 Search in Google Scholar

Roy, P.D., Smykatz-Kloss, W. (2007): REE geochemistry of the recent playa sediments from the Thar Desert, India: an implication to playa sediment provenance. Chemie der Erde -Geocheistry, 67, pp. 55–68. RoyP.D. Smykatz-KlossW. 2007 REE geochemistry of the recent playa sediments from the Thar Desert, India: an implication to playa sediment provenance Chemie der Erde -Geocheistry 67 55 68 10.1016/j.chemer.2005.01.006 Search in Google Scholar

Oyinloye, A.O., Obasi, R. (2006): Geology, geochemistry and geotectonic setting of the Pan-African granites and charnockites around Ado-Ekiti, southwestern Nigeri. Pakistan Journal of Scientific and Industrial Research, 49(5), pp. 299–308. OyinloyeA.O. ObasiR. 2006 Geology, geochemistry and geotectonic setting of the Pan-African granites and charnockites around Ado-Ekiti, southwestern Nigeri Pakistan Journal of Scientific and Industrial Research 49 5 299 308 Search in Google Scholar

Ukaegbu, V.U., Ekwueme, B.N. (2005): Petrogenetic significance of rare earth element behavior in the basement rocks of southern Obudu Plateau, Bamenda Massif, southeastern Nigeria. Chinese Journal of Geochemistry, 24, pp. 129–135. UkaegbuV.U. EkwuemeB.N. 2005 Petrogenetic significance of rare earth element behavior in the basement rocks of southern Obudu Plateau, Bamenda Massif, southeastern Nigeria Chinese Journal of Geochemistry 24 129 135 10.1007/BF02841155 Search in Google Scholar

Feng, R., Kerrich, R. (1990): Geochemistry of fine-grained clastic sediments in the Archean Abitibi greenstone belt, Canada: Implications for provenance and tectonic setting. Geochimica et Cosmochimica Acta, 54(4), pp. 1061–1081. FengR. KerrichR. 1990 Geochemistry of fine-grained clastic sediments in the Archean Abitibi greenstone belt, Canada: Implications for provenance and tectonic setting Geochimica et Cosmochimica Acta 54 4 1061 1081 10.1016/0016-7037(90)90439-R Search in Google Scholar

Papike, J.J., Shearer, C.K., Simon, S.B., Shimizu, N. (1988): Lunar pyroxenes: Crystal chemical rationalization of REE zoning, pattern, and shapes and abundances—an ion microprobe investigation. Abstracts of the Lunar and Planetary Science Conference, 19, pp. 901–902. PapikeJ.J. ShearerC.K. SimonS.B. ShimizuN. 1988 Lunar pyroxenes: Crystal chemical rationalization of REE zoning, pattern, and shapes and abundances—an ion microprobe investigation Abstracts of the Lunar and Planetary Science Conference 19 901 902 Search in Google Scholar

Weill, D.F., Drake, M.J. (1973): Europium anomaly in plagioclase feldspar: Experimental results and quantitative model, Science, 180(4090), 1059–1060, DOI:10.1126/science.180.4090.1059. WeillD.F. DrakeM.J. 1973 Europium anomaly in plagioclase feldspar: Experimental results and quantitative model Science 180 4090 1059 1060 10.1126/science.180.4090.1059 17806582 DOI öffnenSearch in Google Scholar

Boynton, W.V. (1984): Cosmochemistry of the rare earth elements: Meteorite studies. In: Rare Earth Element Geochemistry, Henderson P. (ed.). Elsevier: New York, pp. 63–114, DOI:10.1016/B978-0-444-42148-7.50008-3. BoyntonW.V. 1984 Cosmochemistry of the rare earth elements: Meteorite studies In: Rare Earth Element Geochemistry HendersonP. (ed.). Elsevier New York 63 114 10.1016/B978-0-444-42148-7.50008-3 DOI öffnenSearch in Google Scholar

Ross, P.S., Bédard J.H. (2009): Magmatic affinity of modern and ancient subalkaline volcanic rocks determined from trace-element discriminant diagrams. Canadian Journal of Earth Sciences, 46(11), pp. 823–839, DOI:10.1139/E09-054. RossP.S. BédardJ.H. 2009 Magmatic affinity of modern and ancient subalkaline volcanic rocks determined from trace-element discriminant diagrams Canadian Journal of Earth Sciences 46 11 823 839 10.1139/E09-054 DOI öffnenSearch in Google Scholar

Bowden, P., Bennett, J.N., Whitley, J.E., Moyes, A.B. (1979): Rare earths in Nigerian mesozoic granites and related rock. Physics and Chemistry of the Earth, 11, pp. 479–491, DOI:10.1016/0079-1946(79)90045-4. BowdenP. BennettJ.N. WhitleyJ.E. MoyesA.B. 1979 Rare earths in Nigerian mesozoic granites and related rock Physics and Chemistry of the Earth 11 479 491 10.1016/0079-1946(79)90045-4 DOI öffnenSearch in Google Scholar

Valdecir, J. (1993): Petrogenesis and tectonic setting of the Neoproterozoic Capituva k-syenitic massif, SW Minas Gerais, Brazil. Revista Brasileira de Geociencias, 23, pp. 129–138. ValdecirJ. 1993 Petrogenesis and tectonic setting of the Neoproterozoic Capituva k-syenitic massif, SW Minas Gerais, Brazil Revista Brasileira de Geociencias 23 129 138 10.25249/0375-7536.1993232129138 Search in Google Scholar

Najime, T., Abaa, S.I., Magaji, S. (2012): Petrology and rare earth elements (REE) distribution patterns of magmatic rocks in Gboko Area, Lower Benue Trough Nigeria: implication for tectonic evolution. Global Journal of Geological Sciences, 10(1), pp. 47–58. NajimeT. AbaaS.I. MagajiS. 2012 Petrology and rare earth elements (REE) distribution patterns of magmatic rocks in Gboko Area, Lower Benue Trough Nigeria: implication for tectonic evolution Global Journal of Geological Sciences 10 1 47 58 Search in Google Scholar

Yang, X., Yang, X.Y., Zheng, Y., Le Bas, M. (2003): A rare earth element-rich carbonatite dyke at Bayan Obo, Inner Mongolia, North China. Mineralogy and Petrology, 78, pp. 93–110. YangX. YangX.Y. ZhengY. Le BasM. 2003 A rare earth element-rich carbonatite dyke at Bayan Obo, Inner Mongolia, North China Mineralogy and Petrology 78 93 110 10.1007/s00710-002-0220-5 Search in Google Scholar

Sridhar, N., Mallikarjuna, R., Reddy, Nagendrababu, G. (2018): Quartz syenites from the Prakasam alkaline province, Southern India; A comparative study with special emphasis on their rare earth element contents. Journal of India Geophysical Union, 22(5), pp. 507–517. SridharN. Mallikarjuna ReddyR. NagendrababuG. 2018 Quartz syenites from the Prakasam alkaline province, Southern India; A comparative study with special emphasis on their rare earth element contents Journal of India Geophysical Union 22 5 507 517 Search in Google Scholar

Ukaegbu, V.U., Beka, F.T. (2007): Petrochemistry and geotectonic significance of enderbite-charnockite association in the Pan-African Obudu plateau, southeastern Nigeria. Journal of Mining and Geology, 43(1), pp. 1–14. UkaegbuV.U. BekaF.T. 2007 Petrochemistry and geotectonic significance of enderbite-charnockite association in the Pan-African Obudu plateau, southeastern Nigeria Journal of Mining and Geology 43 1 1 14 10.4314/jmg.v43i1.18859 Search in Google Scholar

Mbongue, N.J.L., Ngnotue, T., Nlend, N., Suh, C.E. (2014): Origin and evolution of the formation of the Cameroon Nyong series in the western border of the Congo Craton. Journal of Geosciences and Geomatics, 2(2), pp. 62–75. MbongueN.J.L. NgnotueT. NlendN. SuhC.E. 2014 Origin and evolution of the formation of the Cameroon Nyong series in the western border of the Congo Craton Journal of Geosciences and Geomatics 2 2 62 75 Search in Google Scholar

Oroh, S. (2018): Geochemical and petrogenetic study of the charnockitic rocks of Akure and Ekiti areas, southwestern, Nigeria. M. Sc. Thesis. University of Ibadan, Department of Geology, 128 p. OrohS. 2018 Geochemical and petrogenetic study of the charnockitic rocks of Akure and Ekiti areas, southwestern, Nigeria M. Sc. Thesis. University of Ibadan, Department of Geology 128 p. Search in Google Scholar

Field, D., Drury, S.A., Cooper, D.C. (1980): Rare-earth and LIL element fractionation in high grade charnockitic gneisses, south Norway, Lithos, 13(3), pp. 281–289. FieldD. DruryS.A. CooperD.C. 1980 Rare-earth and LIL element fractionation in high grade charnockitic gneisses, south Norway Lithos 13 3 281 289 10.1016/0024-4937(80)90074-2 Search in Google Scholar

Weaver, Barry L. (1980): Rare earth elements geochemistry of Madras granulites. Contributions to Mineralogy and Petrology, 71(3), pp. 271–279. WeaverBarry L. 1980 Rare earth elements geochemistry of Madras granulites Contributions to Mineralogy and Petrology 71 3 271 279 10.1007/BF00371668 Search in Google Scholar

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