The CC includes a well-preserved Archaean (Ntem Complex) and Palaeoproterozoic domains (Nyong Series) recording the Precambrian crust formation history of Cameroon [6] [8] . The Ntem Complex is predominantly made of Archaean rocks (3.1 - 2.5 Ga) that were partially reworked during the Palaeoproterozoic Transamazonian cycle [6] [9] - [12] . Greenstone belts though volumetrically less, form important litho units within this complex, and show intrusive relationships with the basement rocks. The Archean basement rocks include high grade charnockites and undifferentiated tonalite-trondhjemite-granite (TTG) suite of rocks [6] [11] [13] [14] . The Palaeoproterozoic Nyong Series crops out to the West and East of the Ntem Complex (Figure 1) [15] . It is part of the Palaeoproterozoic Transamazonian belt, which extends from Central Africa to northeastern Brazil [6] [16] - [18] . The Nyong Series consist mainly of high-grade gneissic rocks, including biotite-hornblende gneiss, charnockite, garnet-amphibole-pyroxenite and Banded Ion Formation (BIF). Pan-African intrusives cut across the Nyong Series rocks and include weakly metamorphosed diorite, granodiorite and syenite, in addition to post-tectonic dolerites at few locations [6] [18] .

The ~600 ± 70 Ma CAFB is a major collisional belt that underlies the region from the West African Craton to East Africa [12] [19] . It extends in parts of Nigeria, Cameroon, Chad, Central African Republic and Sudan to Uganda in the further east [19] . According to their age, three lithological domains have been identified in the CAFB in Cameroon, namely the Adamawa-Yadé (AYD), Yaoundé and Northwestern Cameroon domains [12] [20] .

The Adamawa-Yade Domain [12] [20] is the largest domain of the CAFB in Cameroon, dominated by 640 - 610 Ma, syn- to late-collisional high-K calc-alkaline granitoids (Figure 1). These granitoids intrude high-grade gneisses that represent a Palaeoproterozoic basement, which was likely dismembered during the Pan-African assembly of western Gondwanaland [10] [12] [20] . [20] [21] classified the rocks of the AYD into three main groups, viz. a) Large supracrustal blocks of Palaeoproterozoic metasedimentary rocks and orthogneisses with assimilated Archaean crust similar to the Ntem Complex, b) 612 - 600 Ma, low- to medium-grade metasedimentary and metavolcaniclastic rocks, and c) 640 - 610 Ma syn- to late-tectonic granitoids of transitional composition and crustal origin [12] .

The Yaoundé Domain consists of an extensive tectonic nappe that was thrusted onto the CC during the Pan-African collision [6] [12] [20] [22] . This domain is analogous to the Gbayas and Sergipano nappes in Central African Republic and Brazil, respectively. Thrust slices of metasedimentary rocks with poorly constrained ages of ~626 Ma [21] are common in the Yaoundé Domain [6] [7] [12] suggested that the detrital material was derived from juvenile Palaeoproterozoic and Neoproterozoic sources in the southern part of the AYD, as well as from the Palaeoproterozoic Nyong Series in the CC.

The Northwestern Cameroon Domain is located to the west of the Tcholliré-Banyo Fault (TBF), along the western border of Cameroon and extends into eastern Nigeria. It includes a variety of rock types, namely a) medium- to high-grade schists and gneisses of the ~700 Ma Poli series, b) ~660 - 580 Ma calc-alkaline granitoids (diorite, granodiorite, and granite), c) anorogenic alkaline granitoids, and (d) low-grade sedimentary and volcanic basin sequences [12] [20] . It is generally believed that the CAFB was formed during the Neoproterozoic collision of the West African Craton with the Congo Craton [20] . [20] proposed a three-phase evolution, which began by the emplacement of calc-alkaline granitic rocks (670 - 660 Ma), followed by crustal thickening, high- grade metamorphism, calc-alkaline magmatism (640 - 610 Ma), and finally overprinted by post-collision nappe formation, sub-alkaline to alkaline magmatism (600 - 545 Ma) and molasse basin sedimentation.

Depending on the grain size, granites are divided into coarse, medium and fine grained. Coarse grained granites outcrops are well exposed on the beds of Mape River and dam. They are massive and gray in color, made of feldspar phenocryst (4 cm × 2 cm ) and quartz ( 1 cm × 0.5 cm ) molded by biotite and amphibole flakes. Granites are intruded by mafic dyke oriented NE-SW (Figure 4(a)) of about ten meters long over fifteen centimeters wide. Thin secondary quartz and epidote veins (3 to 6 meters long and up to 3 cm wide) cross-cuts the outcrop, this could be a local deformation feature.

Medium-grained granites are located on the stream bed of Mape River at the Bridge level on Magba-Bankim road and the outcrops are exposed in the slab form ( 400 m long and 100 m wide). These rocks are massive, and at outcrop scale display pink color due to the abundance of potassium feldspar crystals. In Magba area, these rocks are gray in color, made of plagioclase phenocrysts, occur as relics in mylonitized host rocks.

Coarse-to-medium grained granites and protomylonites shows both magmatic stage pre-full crystallization fabric (pfc) and also solid-state deformation fabric. The magmatic stage fabric is defined either by the randomly

oriented euhedral and subhedral feldspar phenocrysts or by an average sub-parallel alignment of the K-feldspar megacrysts in the less deformed granite. The mylonitic foliation (Sm), defined mainly by the preferential alignment of feldspar augen, ribbons of quartz, biotite and sericite streams, are subparallel to the magmatic stage deformation fabric.

Fine-grained granites occur as leucocratic at Mfendagnam and hololeucocratic at Mbakop (Figure 4(b)), often cross-cut by quartzofeldspathic veins. Essential minerals are millimetric sized quartz and feldspar. In Mfendagnam, the leucocratic fine grained granites occur in the dauphin back form (Figure 4(c)) and shark up to 1.5 m high, 8 m long and 2 m wide.

These rocks are exposed in the areas Mbakop, Nkoula, Mfendangam and Mape dam. In Mbacop, orthogneisses are confined to the slopes of the MbaKop hill and occur in the form of ball and slab (6 m long and 4 m wide). Biotite flakes, feldspar and quartz crystals are found in the dark frame. Magmatic flow is evidenced by the alignment of feldspars and quartz crystals. In Nkoula and Mfendagnam areas, the foliation is defined by alternating dark mafic and clear quartzo-feldspthic bands. Feldspar and quartz minerals are millimetric size (2 mm × 1 mm) and well aligned in preferential direction.

“σ” porphyroblasts of feldspar are common in Mfendagnam migmatites Amphibolite intrusions are seen in local scale in few outcrops (Figure 4(d)). In Mape dam area, the foliation is defined by alternating dark bands composed of ferromagnesian minerals and clear quartzo-feldspathic bands. The biotite lamellae (1 mm × 0.5 mm) are observed in the dark bands. At places, migmatisation features are marked by the combination of granitic and gneissic components along with amphibolite intrusions.

Migmatitic outcrops are noticed in Mbakop, Mape dam and Chissa hill areas. In general, migmatites mark the passage of high-temperature metamorphic rocks to crustal igneous rocks. They result from the mineralogical reorganization by insitu partial melting of pre-existing rocks or granitic liquid injection in fractures.

In Mbakop area, these rocks are foliated, leucocratic and marked by a compositional banding characterized by alternating bands of gneisses and amphibolites. Later intrusions that are broadly parallel to the gneissic foliation are aplite and pegmatite veins and a metatexitic banding marked by vein injections. The migmatitic rock is also made of a light-colored mobilizate composing quartz and feldspar which could be the melt product, and of a restitic component constituting biotite, hornblende and pyroxene.The rock unit appears to be stretched and remobilised by quartzo-feldspathic components. These observations suggest that Mbakop migmatites are probable diatexites because of their heterogeneous appearance with the preponderant neosome (molten portion) in relation to paleosome (unmelted portion). The rock is also traversed by quartzo-feldspathic pegmatite vein probably

of granitic origin. Imbricated amphibolite boudins are also observed.

Mape dam, the migmatites are foliated, melanocratic, found in association with the othogneisses, marked by the presence of large crystals of feldspar (10 cm × 6 cm) injected into the gneissic unit during the partial melting of the parent amphibolite, then molded and guided by mafic minerals during deformation. Hence these feldspar crystals have a recrystallization tail and show the sinistral sense of shear (Figure 4(e)). Biotite occurs in the form of lamellae (1cm × 0.5 cm) and confined to the dark portion that constitutes restite. Quartz occurs as fine gains (0.8 cm × 0.6 cm) within the melanocratic frame. All these features suggest that Mape migmatites are metatexitic. The migmatites of Chissa hill area are mainly dark, melanocratic and marked by intense folding of leucosomes.

In Manouri area the metagabbro outcrops are noted in 100 m long over 30 m wide area. The rock is dark greenish in color and highly banded, having several fractures oriented in several directions and intersecting the sub vertical mylonitic foliation. The rock is traversed by quartzo-feldspathic veins of varying thickness (1 cm to 20 cm) parallel to the NE-SW banding direction. NE-SW trending prominent sub vertical stretching lineation defined by elongated feldspar grains on the foliation plane is recorded. Veins that host feldspar crystals are also molded by melted feldspar matrix. Joints (1 cm to 20 cm thickness) host molded feldspar porphyroblasts in the thin matrix of microcrystals of the same mineral. In places there is a feldspar vein system in the form of a spider web around the centimetric to decimetric block of gabbro (Figure 4(f)). Outcrops exhibit dome and basin structures which demonstrate lateral constraints.

The mafic dykes are exposed in Mape dam and Mfembalouh area on Magba-Mbakop road. In Mape dam area, they occur as NE-SW intrusions of 10m long and 15cm width and are associated to migmatite and orthogneiss (Figure 4(g)). The rock is massive with aphyric texture and intrudes the granite outcrop. In Mfembalouh, these rocks are massive, oriented in NE-SW direction, occur in relatively wider extent (30 m long and 10 m wide) and is highly fractured, mainly in the NW-SE and NE-SW directions, forming a kind of grid system (Figure 4(h)).

Mylonites are well distributed in the study area, along the NE and SE of Magba hill, in Manouri, Nkoula areas and Chissa hill. Depending on the extent of deformation, and subsequent retention of the parent rock (granite), the mylonites are divided into three groups: protomylonites (initial rock proportion ≥ 50%), mylonites (10% ≤ initial rock proportion ≤ 50%), and ultramylonites (initial rock proportion ≤ 10%). Protomylonites and mylonites are noticed in Magba hill, Chissa hill, Mfendagnam, and Mbakop areas while the ultramylonites are noticed in Magba and Chissa hill areas.

In Magba area, the protomylonites occur as massive slabs, with feldspars and quartz as major minerals that constitute the rock. Thin secondary veins filled with epidote and/or chlorites are noticed traversing in all directions, while at some places the quartzo-feldspathic veins are observed intersecting the mylonitic foliation. Few mafic material injections (amphibolite) of varying thickness (3 - 10 cm) are traversed parallel to the foliation. Depending on cross-cutting chronology, mafic injections could be older than quartzo-feldspathic veins. In NE of Magba hill area, the mylonites have similar behavior as the earlier outcrops described, except that at local scale, magmatic quartzo-feldspathic ingestions (~0.5 m thick) are noticed containing large feldspar porphyoclasts oriented perpendicular to the mylonitic foliation. At Mfendagnam area, the rock still retains few probable protholithic structures such as aligned feldspar and quartz porhyroclasts reoriented along the mylonitic foliation. The clasts exhibit recrystallization tails of “σ” shape symptomatic of a sinistral shearing movement. The outcrop is traversed by quartz veins subparallel to the low amplitude mylonitic foliation. At Chissa hill area, the mylonites are locally traversed by quartzo-feldspathic veins those are variably folded.

Ultramylonites are well exposed at the NE and SE of Magba hill, Nkoup river bed and Chissa hill, and are distinct from other rock types of the study area due to the pronounced enrichment of chlorite. Feldspar porphyroclasts are fewer and have rounded to elliptical shape, sparsely occur in a very fine groundmass composed of quartz, feldspar and micas. Intense mylonitic foliation (Sm), defined by subparallel alignment of biotite and quartz ribbons in the matrix, give rise to subparallel dark and clear bands enriched and devoid of biotite respectively (Figure 4(i)). Stair stepping of the feldspar porphyroclasts with their long axis at an acute angle with the mylonitic foliation, together with strike-slip sheared quartzo-feldspathic veins indicates a sinistral sense of shear movement of the rock. Ultramylonite zones display extreme grain size reduction and near absence of visible feldspar porphyroclasts and neocrystallisation of chlorite and sericite transformed the rock into foliated quartz- chlorite rock or phyllonite. The different subzones comprising protomylonite, mylonite and ultramylonite within the sheared granite corresponds to the progressive increase in strain, as evident from grain size reduction, progressive disappearance of feldspar porphyroclasts and generation of sericite mica and chlorite, decrease in angle between the S- and C-planes and increasing aspect ratios of the quartz ribbons. Heterogeneous deformation greatly modified the grain size and texture of the rock within Magba shear zone.

The granites are coarse to fine-grained and predominantly porphyritic in nature (Figure 5(a) and Figure 5(b)). They are composed of quartz (28%), orthoclase (15%), plagioclase (10%), pyroxene (8%), biotite (7%), amphibole (5%), microcline (5%) and muscovite (3%) as principal minerals, while allanite (4%), sphene (2%), apatite (2%), epidote (2%) and opaques (1%) are the accessory minerals. Secondary minerals are represented by myrmekite (2%), chlorite (1%), sericite (3%) and perthite (2%). Quartz is in the form of polycrystalline ribbons of varying size having gears and grain boundary migration (Figure 5(b)). Quartz grains occasionally react with plagioclase to form myrmekites at the grain boundaries (Figure 5(c)).

Plagioclase crystals are sub-euhedral and exhibit albite twins. Some crystals underwent sericitization while orthoclase crystals underwent perthitization reactions (Figure 5(d)). Pyroxene is in the form of sub-euhedral, moderately elongated phenocrysts. Amphibole is represented by the green hornblende, occur in the sheet form similar to the amphibole fish. It contains sphene inclusions and associated with biotites and pyroxenes. Biotites occur as elongated fine fibres, mostly transformed into chlorite. Some biotite fibres contain opaque inclusions while others are resorbed by quartz. Sphene is in the form of columnar rod or sub-rounded form with their characteristic twins.

Textures that characterize orthogneisses include porhyroblastic, granoblastic (Figure 5(e)) and lepidoblastic. The major minerals are quartz (30%), plagioclase (20%), orthoclase (15%), pyroxene (12%), and amphibole (12%). Chlorite (8%) is secondary mineral while sphene (2%) and epidote (1%) are accessory minerals. Quartz is more abundant in the rock and is in the form of polycrystalline ribbons composed of both porphyroblasts and microblasts. Elongated ribbons of quartz show the evidence for dynamic recrystallisation in the form of development of sub grains, their rotation and recrystallization (Figure 5(f)).

Quartz porphyroblasts are abundant in Mape dam orthogneiss while quartz microblasts filling the mineral interstices and cracks are observed in the orthogneisses of Mbakop area. Quartz is also present in the form of elongated fibers forming the pressure fringe around the pyrite sub rounded mineral. Plagioclase is in the form of sub-euhedral crystals generally molded by biotite and chlorite. In places plagioclase crystals present displaced grain fragment or micro fault and curved shapes while others display zoning, typical for magmatic crystallization. Biotite is in the form of flake and fibers with more or less frayed edge. Locally biotite is transformed into

Qtz = quartz, Pl = plagioclase, Bt = biotite, Or = orthoclase, Mi = microcline, Mus = muscovite, Sph = sphene, Px = pyroxene, Op = opaques, Zrn = zircon, Ap = apatite, Ep = epidote, Aln = allanite, Tr = tourmaline, Amp = amphibole, Leu = leucoxene

chlorite. Amphibole (green hornblende) is anhedral or sub-euhedral, flaky sometimes occurs in the form of “amphibole fish”. Orthoclase is less abundant in the rock and occurs as large sub-euhedral and anhedral crystals with carlsbad twins, often display cracks filled with biotite. Pyroxenes occur in clusters in Mape dam orthogneisses, are diamond-shaped while in Mbakop orthogneisses, they occur as twinned or zoned slats (Figure 6(a)). Sphene is very rare in Mape dam orthogneiss, but commonly seen in those of Mbakop, while acicular epidote is noticed in plagioclase porphyroblasts.

Migmatites exhibit grano-porphyroblastic texture. The mineralogy is quartz (40%), biotite (15%), myrmekite (2%), chlorite (8%), plagioclase (25%), apatite (4%) microcline (5%) and opaque (1%). In Mape dam, there are two generations of quartz, the first generation being exhibited as monocrystalline ribbons having gears with undulatory extinction while the second-generation quartz is the product of recrystallization and filled along the interstices between the primary minerals resulting in migmatitic foliation to the rock. Plagioclase occurs as sub-

euhedral crystals with sub-rounded contours molded by recrystallized quartz crystals and biotite lamellae. Some crystals have fractures brands and kink structures due to tectonic stresses. Most of the crystals are deformed and contain pressure shadows or recrystallization tails filled by biotite or quartz (Figure 6(b)). Biotite molds feld- spar and quartz porphyroblasts giving the appearance of spider network. Some flakes are transformed into chlorite (Figure 6(c)). Microcline is anhedral and presents slightly curved polysynthetic twins of albite and pericline forming a shimmering fine grid with low to very low relief.

Metagabbros of Magba region exhibit porhyroblastic textures (Figure 6(d)) and made of plagioclase (40%), microcline (15%), orthoclase (8%), pyroxene (5%), amphibole (4%) and biotite (2%) as primary minerals while only sericite (25%) is the secondary mineral and opaque (1%) accessory mineral. Plagioclase crystals are more abundant, are sub-euhedral and exhibit polysynthetic twinning. Though very limited, also occur as inclusions in orthoclase. Sericite occur in the form of pasty bands, developed due to sericitization of plagioclase (Figure 6(d)). Microcline crystals sometimes contain amphibole inclusions. Orthoclase crystals are less abundant in the rock while pyroxene is in the form of elongated strips with rectangular sections. Amphiboles are very rare in the rock and occur as thin flakes. Opaque minerals are euhedral sometime with hexagonal form and disseminated in the rock.

These rocks exhibit cataclastic textures marked by alternating layers of dark and light colored minerals. Crushed minerals are indistinguishable microscopically. Some phenocrysts that resisted crushing are visible such as amphibole (30%), orthoclase (25%), chlorite (20%), pyroxene (15%), epidote (6%), zircon (5%) and oxides (4%). Amphibole is represented by the green hornblende and occurs as clusters of curved branching flakes that are a characteristic of Magba dykes (Figure 6(e)). Sometimes the amphiboles occur as sub-rounded to sub-euhedral crystals, as well as like “amphibole fish” shape suggesting their growth during deformation. Chlorites are the alteration products of amphiboles and they fill the interstices left by previously crystallized minerals. Pyroxenes occur as phenocrysts of uneven square or diamond-shaped. Orthoclase occurs as largely fractured anhedral phenocrysts of variable sizes, includes almond-shaped and “σ” type porphyroclasts, indicating the sinistral shear sense these rocks had undergone. Few orthoclase crystals also bear amphibole and opaque inclusions. Epidotes occur as euhedral to sub-euhedral crystals. In the matrix they are anhedral while in the veins they are particularly in euhedral form, oriented perpendicular to the walls of the vein leaving gap in the center (Figure 6(f)). Opaques are less abundant, euhedral to sub-euhedral and are found in fractures and mineral interstices. Zircon is the least visible mineral in the rock. It is euhedral with high relief and presents sometimes a corona due to its radioactivity.

Strain heterogeneity within the Magba Shear Zone is evident from the development of proto- to ultramylonite zones, with granoclastic (Figure 7(a)), ocelar mylonitic texture (Figure 7(b)), and cataclastic textures (Figure 7(c)) respectively for protomylonite, mylonite and ultramylonites. Primary minerals are quartz (20 %), orthoclase (15%), plagioclase (10%), biotite (8%), amphibole (6%), microcline (5%); secondary minerals are sericite (8%), myrmekite (2%) and chlorite (10%) while zircon (2%), sphene (2%), tourmaline (1%), epidote (1%), apatite (1%), leucoxene (5%) and opaques (4%) are accessory minerals. Pyroxenes are confined to mylonites while amphiboles and microclines are observed in mylonites and ultramylonites. Protomylonites are characterized by weakly developed fabric, defined by the elongated quartz and feldspar grains. Quartz and orthoclase porphyroclasts yield to brittle failure producing fragmented grains and also to crystal plastic deformation resulting in deformation lamellae and grain refinement through recrystallization (Figure 7(d)).

Quartz phenocrysts exhibit globular and granular shapes with undulatory extinction and are scattered in the crushed recrystallized matrix while microcrysts form bands parallel to biotite (“biotite fish”) layers giving the rock a curved mylonitic foliation (Figure 7(e)). At Mbakop, some biotite flakes are folded and present curved pressure shadow (Figure 7(f)). Some quartzofeldspathic layers are folded under S type shape indicating the sinistral sense of shear the rock had undergone (Figure 8(a)).

Most of plagioclase and orthoclase porphyroclasts exhibit “σ” or “δ” (Figure 8(b)), recrystallization tails and other rolling structures giving the sinistral shear sense to the rock. Highly fractured plagioclases are also present (Figure 8(c)). Sericitization is noted only in protomylonites while myrmekitization is observed in protomylonites and mylonites. Perthitic texture marked by plagioclase band containing albite islets is also noted. Feldspar phenocrysts exhibit simple and staircase type displacements (Figure 8(d)) and “chevron”/“kink” type deformation (Figure 8(e)).

Amphiboles are represented by green hornblende and glaucophane. Green hornblende is sub-euhedral and occur as curved tracks associated with biotite, and also as “amphibole fish” (Figure 8(f)), indicating their emplacement during deformation. Retrograde metamorphism marked by amphibole converting to chlorite is observed at few places. Opaques and zircon inclusions are observed in the margins of biotites, and such inclusions are identified in orthoclase also. Most biotite flakes underwent early chloritization. Leucoxene and tourmaline are euhedral and only found in ultramylonite while apatites are found in protomylonites and mylonites.

Major and trace element compositions of the analyzed samples are given in Table 2.The rocks exhibit important variations in concentrations of major elements. They are basic to acid with low to high SiO₂ concentrations with

lowest (48.61wt.%) value in metagabbro and the highest (73.40 wt.%) in mylonite. They plot in the gabbro, monzodiorite, monzonite syenite, quartz monzonite, granodiorite and diorite field in the diagram of [26] (Figure 9). In the A/CNK and A/NK diagram after [27] the all the samples are metaluminous with A/CNK and NK/A ratios ranging from 0.38 to 0.87, and 0.40 to 1.23 respectively and Al₂O₃ values ranging from 11.54 to 16.06 wt.% (Figure 10). The Al₂O₃ (10.68 - 16.06) and Fe₂O₃ contents (0.53 - 10.55 wt.%) are high while MgO (0.23 - 9.12 wt.%) and MnO (0.01 - 0.17 wt.%) contents are low. CaO (0.34 - 11.4 wt.%), Na₂O (2.38 - 5.22 wt.%), K₂O (1.31 - 9.85 wt.%), TiO₂ (0.01 - 2 wt.%) and P₂O₅ (0.04 - 0.84 wt.%) contents are low to high with highest value in metagabbro (TiO₂ = 2 wt.%, and P₂O₅ = 0.84 wt.%). TiO₂ bearing mineral phases are abundant in mylonite and mafic dykes and rare in metagabbro. The loss on ignition (L.O.I = 0.20 - 1.76 wt.%) values are low, attesting to the freshness of the rocks or the low proportion of fluid in the magma. This content is justified by the rarity of secondary minerals in the rock. All the sample have Na₂O/K₂O ratios ranging from 0.27 to 2.18 and K₂O/Na₂O from 0.46 to 3.59, showing the sodic character of rocks and plot in high-k calc-alkaline and shoshonitic field of the diagram after [28] (Figure 11).

Bivariate plots of MgO with SiO₂, CaO and Ni show a distinct linear regression (either positive or negative slope) for the mafic rocks of Magba. On the Harker diagrams (Figure 12), the abundances of TiO₂, Al₂O₃, MnO,

MgO, CaO, Na₂O, Fe₂O₃ total, and P₂O₅ decrease with increasing SiO₂. However, K₂O correlates positively with SiO₂, which may imply that alkali feldspar persisted in the melt phase until the later stages of magmatic evolution.

Within the minor and trace element suites, Cr (08.81 - 451.52 ppm), Vanadium (3.25 - 747.53 ppm), Cuper (0.14 - 144.83) and Zn (5.54 - 121.72 ppm), are dominant. Co (0.82 - 59.31 ppm), Sc (0.50 - 33.89 ppm) and Ni (0.73 - 144.83 ppm), contents are low to moderate. Barium (60.63 to 2662.86 ppm) content in orthogneiss is higher than in other rocks (Table 2). The lowest contents in Hf, Zr, and Pb are also obtained in mylonite (Table 2).

Samples are characterized by low to high Sr (36.40 - 1361.21 ppm) and Y (1.29 - 89.19 ppm) but low Yb (0.05 - 6.95 ppm) concentrations (Table 2). They are enriched in LREE but depleted in HREE, with (La/Yb)N = 1.11 - 197.67 (chondrite normalized value are after [29] . They present a flat HREE pattern and weakly negative to positive Eu anomalies (dEu = 0.14 - 1.44; dEu = EuN/SQRT (SmN _ GdN)) in chondrite normalized REE diagram and variable fractionation (Table 2). Therefore, two distinct types of REE patterns, viz., with and without Eu negative anomaly (Figure 13) was observed with light rare earth elements (LREE) enrichment depicting the evolution of Magba rocks probably through fractional crystallization.

Patterns show also enrichment in Ba, K, Pb, Nd, Sm and depletion in Nb, U, La, Ce, Pr, Yb and Ti in the primitive mantle normalized spidergram (Figure 14; primitive mantle values were taken after [30] . The chondrite-normalized [29] patterns present also the parallel spectra for gabbro and mafic dykes samples, negative Ce

anomalies and higher (La/Yb)N value in mylonite (sample NT2). Two types of trend in trace elements distribution, viz. i) depletion of HFSE (Sr, Ta Nb, Rb, Ba, Y, Hf) and positive anomalies of Cs, Nd, Sm, U and Ti with V-shaped strong negative anomaly of Eu in metagabbro, and ii) enrichment of LIL elements (Rb, K, Sr, Th) and depletion of Nb, Hf, Zr, Rb in the Magba rocks have been also observed (Figure 14).

In general, rocks of Eu positive signature have more variation in the HREE and comprise pronounced positive anomalies of Pb and Zr.

The nature of these patterns suggests complex evolution of these rocks, which would have gone through multiple magmatic processes.