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Field Observations, Petrography, and Microstructures of Granite from Abeokuta Southwestern Nigeria

Published Online: 04 Feb 2022
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Received: 03 Aug 2021
Accepted: 24 Nov 2021
Journal Details
License
Format
Journal
eISSN
1854-7400
First Published
30 Mar 2016
Publication timeframe
4 times per year
Languages
English
Introduction

Granite is the most abundant rock in the continental crust. A-type granite is proposed to originate from the fractional crystallization of the upper mantle [1,2,3,4,5,6]. Abeokuta, the study area, shares a boundary with the sedimentary rocks of the Dahomey Basin. Large crystals of K-feldspar with the preferred alignment typifies the granite of Abeokuta (Figure 1). Arguments have been put forward to suggest the origination of these megacrysts in granite. In some of the literature, it is agreed that phenocrysts are formed through early growth by crystallization from the molten portion of magma [7,8,9,10,11], while the later developing porphyroblasts arise from a water-rich fluid phase usually in the subsolidus environment [12,13,14,15,16]. The current study uses field observations and petrographic features to determine the origin of K-feldspar megacrysts in the granite of Abeokuta.

Figure 1

a) Field photograph showing dispersed K-feldspar megacrysts with the preferred alignment from Abeokuta. Megacryts are subhedral to euhedral b) Hand specimen sample of porphyritic granite from Abeokuta showing a large phenocryst of K-feldspar in a matrix of biotite.

Geological Setting

Nigeria is located within the section of Pan-African reactivation 600 + 150 Ma [17, 18] to the east of the West African craton. The older granite suite of Nigeria comprises for the most part tonalitic to granitic calc-alkaline intrusions which were emplaced at a period of about 800–500 Ma ago [19,20,21,22]. The Older Granite suite of Nigeria has been described as a high-level, I-type intrusion [23,24,25]. The phrase ‘Older Granite’ was coined by Falconer [26] to separate the deep-seated, often concordant granites of the Precambrian basement complex of Nigeria from the highly discordant tin-bearing granite which is found in Northern Nigeria. Older Granite is one of the substantial rock units identified in the Precambrian basement complex of Nigeria [27]. Older Granite suites have a wide range of composition that varies from granite through granodiorite, adamellite/quartz monzonite to syenite [27]. The granitic rock of Abeokuta is porphyritic in texture, with phenocrysts of K-feldspar aligned in the preferred direction and thus defining foliation (Figure 1a). Where aligned, the phenocrysts trend in a NW-SE direction on the field. There are quatzo-feldspathic veins and pegmatitic veins of different dimensions running through the granite. Xenoliths of porphyritic mafic rock composition exist within the main porphyritic granite (Figure 2). The sizes of phenocrysts observed on the field vary from a few millimeters to about 10.5 cm in length (Figure 3a).

Figure 2

Field photograph showing a xenolith of porphyritic mafic rock within a felsic, porphyritic granite.

Figure 3

Field photographs showing: a) megacrysts of K-feldspar, b) subhedral-euhedral megacrysts of K-feldspar, c) zoned crystals with concentric inclusions of biotite, d) zoned crystals of K-feldspar with a core rich in biotite inclusion, e) K-feldspar magacrysts with inclusions of biotite-defining zonation, f) Zoned K-feldspar crystal with inclusions of biotite, g) zoned crystal of K-feldspar in porphyritic mafic rock, h) matrix-dominated porphyritic mafic rock with zoned megacrysts of K-feldspar.

Granite has a greater amount of K-feldspar megacrysts (Figure 3a and 3b) as compared to matrix and can be described as megacryst-dominated. Some K-feldspar megacrysts are zoned (Figures 3c–3h), with inclusions of biotite-defining zonation. The inclusions of biotite are arranged in a concentric pattern along the crystal faces of the zoned megacrysts (Figures 3c, 3e, and 3f). K-feldspar megacrysts vary in colour from yellowish, whitish, and in some cases pinkish colouration. The associated mafic porphyritic rock component also shows zoned crystals of K-feldspars (Figures 3g and 3h). The mafic rock components, which occur as enclaves within the porphyritic granite, have micro-phenocrysts aligned in the same direction as the megacrysts in the porphyritic granite (Figure 4).

Figure 4

Field photograph showing enclaves of a pophyritic mafic rock component within porphyritic granite. The micro-phenocrysts, megaphenocrysts, and biotite crystals are all aligned in the same direction.

Materials and methods

Thin sections of porphyritic granite were prepared at the Department of Geology, Obafemi Awolowo University in Ife, Nigeria. The petrographic study was carried out at the Department of Geosciences, University of Lagos using a polarizing microscope, and optical properties of the minerals were studied under both plane-polarized light (PPL) and cross-polarized light (XPL).

Results
Petrography

The granite comprises the following minerals in order of abundance: K-feldspar, biotite, quartz, and plagioclase with apatite occurring as an accessory mineral. The crystals of K-feldspar are subhedral to anhedral in shape and occur as phenocrysts in a matrix of quartz and biotite (Figure 5). K-feldspar is poikilitic, having inclusions of biotite (Figure 5a). A cross-hatched twinning is an indication of the presence of microcline, a type of K-feldspar (Figure 5b). The plagioclase feldspar has polysynthetic twinning, also referred to as albite twinning (Figure 5c). Plagioclase shows a high level of albitization (Figure 5c). K-feldspar exhibits perthitic texture (Figures 5d and 5e). Quartz crystals occur as inclusions in phenocrysts of K-feldspar (Figure 5e), and exhibit a symplectic texture between K-feldspar and plagioclase (Figure 5f). Biotite has crystals with a preferred alignment (Figures 5g and 5h).

Figure 5

Photomicrographs of porphyritic granite showing a) inclusions of biotite in K-feldspar (Kfs), XPL b) tartan twining in K-feldspar (Kfs), XPL c) albitization of plagioclase feldspar (Kfs), XPL d) perthitic texture in K-feldspar (Kfs), XPL e) K-feldspar with perthitic intergrowth and inclusions of quartz (Qtz), XPL f) symplectic texture between K-feldspar and plagioclase (Pl), XPL g) biotite (Bt) crystals with a preferred alignment, PPL h) biotite (Bt) and K-feldspar (Kfs) in close association, XPL.

Discussion

Megacryst K-feldspars are prominent features in Abeokuta granite. For growth of crystals, essential components in the magma must diffuse through the melt to the crystal-melt interface, and also excess or excluded components need to diffuse away from the interface. It has been shown that diffusivities in silicate melts usually reduce in the sequence Na ≥ K > Ca > Al >> Si [28, 29]. Therefore, the rate-limiting event necessary for the crystallization of feldspars and quartz is the attainment of the correct percentages of Si:Al available at the crystal-melt margins. To this end, the megacrystic nature of K-feldspars means that the composition of K-feldspar is highly similar to that of the granitic liquid in terms of the major components that diffuse slowly in silicate melts. Other granite-forming minerals do not share this compositional similarity with the granitic liquid. The time at which K-feldspar starts to crystallize also depends on the bulk chemical composition of the magma. More alkalic magmas will naturally precipitate K-feldspar earlier than those of less-K-rich compositions [30]. Difficulty in the nucleation of K-feldspar has been given as the reason why K-feldspar forms megacrysts; once nucleation commences, it grows rapidly, thus a small number of very large crystals is formed [31]. The phenocrysts of the K-feldspars can be termed megacrysts on the basis of their size, which is several times larger than the plagioclase. This might be due to the low rate of nucleation and the rapid growth rate [9, 32]. However, Moore and Sisson [33] have proposed that K-feldspar grows into larger megacrysts than other minerals in granite because of the similarities in the composition of K-feldspar and the granitic components that diffuse slowly in silicate melts. In most zones, a preferred alignment of the K-feldspar megacrysts forms (Figure 1a), defining foliation. Foliated granite has been reported in the members of the Older Granite suite in other parts of the Basement Complex of Nigeria [34, 35, 19, 36]. These foliations in granitoids can form through magmatic flow [37, 38]. The preferred alignment of crystals suggests that the magma attained a high viscosity and could have occurred in the later stage of crystallization for the preferred orientation to be preserved [39]. Zoning is a common feature in the K-feldspar megacrysts (Figures 3c–3h). Dark inclusions of biotite are displayed in internal zones aligned to the outer margins of megacrysts (Figures 3c and 3e). A number of igneous microtextural features, such as simple twinning and concentric arrangements of inclusions, are typical of K-feldspar megacryst of magmatic origin [8, 40, 41]. Microgranite enclaves have also been (Figure 4) derived, which implies that the megacrysts moved as independent crystals suspended in liquid, and therefore did not develop in situ [42]. The elongation of such microgranitoid enclaves (Figure 4), without the presence of plastic contortion of the minerals provides evidence of magmatic flow [38, 43]. The inclusions within the megacrysts are far smaller than their matrix equivalents, and thus show characteristics specific to magmatic growth, which includes zonal alignment (Figures 3c and 3f) and euhedral shape [8]. K-feldspar megacrysts have been interpreted to be early crystallizing phases [16]. Symplectic intergrowth between K-feldspar and plagioclase can be observed in thin section (Figure 5f), which provides us with a clue about the final crystallization process in the granite under study. Symplectic texture has been reported in granitoids from southwestern Nigeria [44]. Symplectic texture in petrology is characterized by the intergrowth of two minerals that crystallized simultaneously [45]. Symplectic intergrowth in granite has been described by different authors across continents [46, 47]. Replacement of plagioclase by K-feldspar (Figure 5c), as described by Collins [48], appears to be a very common phenomenon. Replacement of plagioclase by K-feldspar at low temperatures has been reported [49], but a high temperature alteration of plagioclase to K-feldspar is also possible [49, 50]. For instance, at a temperature of about 25–350°C, plagioclase feldspars are altered to sericite through weathering [51]. Some of the quartz crystals exhibit a wavy form of extinction. There are minor fractures on some K-feldspar megacrysts (Figure 3c) and micro-fractures on K-feldspar crystals (Figure 5b), which are evidences of deformation. The fact that biotite occurs as inclusions in the K-feldspar follows the Bowen reaction series in which the biotite crystalizes first at a higher temperature before the K-feldspar crystalizes at a much lower temperature (Figure 5a). The K-feldspar has many of the other minerals in the rock present as inclusions, which is an indication of the late-stage crystallization of K-feldspar [8]. The alkali feldspar shows flame perthitic to mesoperthitic structure (Figures 5d and 5e). The formation of perthite has been explained to be a replacement-type reaction (Na-K exchange) that takes place between K-feldspar and plagioclase in an environment of low-moderate differential stress usually accompanying rapid cooling [52,53,54,55,56]. The presence of exsolution lamellae (Figures 5d and 5e) could be found in recrystallized K-feldspar formed at hypersolvus temperatures [37, 57]. Several researchers have used microtextures, such as perthite and myrmekite, as tools to investigate the cooling mechanism of rocks [58,59,60,61], which can also be linked to exsolution and hydrothermal subsolidus activity.

Conclusion

Observations such as the crystal shape of K-feldspars and concentric crystallographic arrangements of inclusions of biotite in K-feldspar have provided evidence supporting a magmatic/phenocrystic origin for K-feldspar megacrysts in Abeokuta granite rather than originating while growing in a solid state as in the formation of porphyroblasts. K-feldspar's inclusion of other minerals and the preferred alignment of K-feldspar magacrysts attributed to magmatic flow suggest late crystallization of K-feldspar.

Figure 1

a) Field photograph showing dispersed K-feldspar megacrysts with the preferred alignment from Abeokuta. Megacryts are subhedral to euhedral b) Hand specimen sample of porphyritic granite from Abeokuta showing a large phenocryst of K-feldspar in a matrix of biotite.
a) Field photograph showing dispersed K-feldspar megacrysts with the preferred alignment from Abeokuta. Megacryts are subhedral to euhedral b) Hand specimen sample of porphyritic granite from Abeokuta showing a large phenocryst of K-feldspar in a matrix of biotite.

Figure 2

Field photograph showing a xenolith of porphyritic mafic rock within a felsic, porphyritic granite.
Field photograph showing a xenolith of porphyritic mafic rock within a felsic, porphyritic granite.

Figure 3

Field photographs showing: a) megacrysts of K-feldspar, b) subhedral-euhedral megacrysts of K-feldspar, c) zoned crystals with concentric inclusions of biotite, d) zoned crystals of K-feldspar with a core rich in biotite inclusion, e) K-feldspar magacrysts with inclusions of biotite-defining zonation, f) Zoned K-feldspar crystal with inclusions of biotite, g) zoned crystal of K-feldspar in porphyritic mafic rock, h) matrix-dominated porphyritic mafic rock with zoned megacrysts of K-feldspar.
Field photographs showing: a) megacrysts of K-feldspar, b) subhedral-euhedral megacrysts of K-feldspar, c) zoned crystals with concentric inclusions of biotite, d) zoned crystals of K-feldspar with a core rich in biotite inclusion, e) K-feldspar magacrysts with inclusions of biotite-defining zonation, f) Zoned K-feldspar crystal with inclusions of biotite, g) zoned crystal of K-feldspar in porphyritic mafic rock, h) matrix-dominated porphyritic mafic rock with zoned megacrysts of K-feldspar.

Figure 4

Field photograph showing enclaves of a pophyritic mafic rock component within porphyritic granite. The micro-phenocrysts, megaphenocrysts, and biotite crystals are all aligned in the same direction.
Field photograph showing enclaves of a pophyritic mafic rock component within porphyritic granite. The micro-phenocrysts, megaphenocrysts, and biotite crystals are all aligned in the same direction.

Figure 5

Photomicrographs of porphyritic granite showing a) inclusions of biotite in K-feldspar (Kfs), XPL b) tartan twining in K-feldspar (Kfs), XPL c) albitization of plagioclase feldspar (Kfs), XPL d) perthitic texture in K-feldspar (Kfs), XPL e) K-feldspar with perthitic intergrowth and inclusions of quartz (Qtz), XPL f) symplectic texture between K-feldspar and plagioclase (Pl), XPL g) biotite (Bt) crystals with a preferred alignment, PPL h) biotite (Bt) and K-feldspar (Kfs) in close association, XPL.
Photomicrographs of porphyritic granite showing a) inclusions of biotite in K-feldspar (Kfs), XPL b) tartan twining in K-feldspar (Kfs), XPL c) albitization of plagioclase feldspar (Kfs), XPL d) perthitic texture in K-feldspar (Kfs), XPL e) K-feldspar with perthitic intergrowth and inclusions of quartz (Qtz), XPL f) symplectic texture between K-feldspar and plagioclase (Pl), XPL g) biotite (Bt) crystals with a preferred alignment, PPL h) biotite (Bt) and K-feldspar (Kfs) in close association, XPL.

Turner, S.P., Foden, J.D., Morrison, R.S. (1992): Derivation of some A-type magmas by fractionation of basaltic magma: an example from the Padthaway Ridge, South Australia. Lithos, 28(2), pp. 151–179. Doi.org/10.1016/0024-4937(92)90029-X TurnerS.P. FodenJ.D. MorrisonR.S. 1992 Derivation of some A-type magmas by fractionation of basaltic magma: an example from the Padthaway Ridge, South Australia Lithos 28 2 151 179 Doi.org/10.1016/0024-4937(92)90029-X 10.1016/0024-4937(92)90029-X Search in Google Scholar

Atherton, M.P. (1993): Granite magmatism. Journal of the Geological Society, 150(6), pp. 1009–1023. Doi.org/10.1144/gsjgs.150.6.1009 AthertonM.P. 1993 Granite magmatism Journal of the Geological Society 150 6 1009 1023 Doi.org/10.1144/gsjgs.150.6.1009 10.1144/gsjgs.150.6.1009 Search in Google Scholar

Soesoo, A. (2000): Fractional crystallization of mantle-derived melts as a mechanism for some I-type granite petrogenesis: an example from Lachlan Fold Belt, Australia. Journal of the Geological Society, 157(1), pp. 135–149. Doi.org/10.1144/jgs.157.1.135 SoesooA. 2000 Fractional crystallization of mantle-derived melts as a mechanism for some I-type granite petrogenesis: an example from Lachlan Fold Belt, Australia Journal of the Geological Society 157 1 135 149 Doi.org/10.1144/jgs.157.1.135 10.1144/jgs.157.1.135 Search in Google Scholar

Jarrar, G.H., Manton, W.I., Stern, R.J., Zachmann, D. (2008): Late Neoproterozoic A-type granites in the northernmost Arabian-Nubian Shield formed by fractionation of basaltic melts. Geochemistry, 68(3), pp. 295–312. Doi.org/10.1016/j.chemer.2006.09.002 JarrarG.H. MantonW.I. SternR.J. ZachmannD. 2008 Late Neoproterozoic A-type granites in the northernmost Arabian-Nubian Shield formed by fractionation of basaltic melts Geochemistry 68 3 295 312 Doi.org/10.1016/j.chemer.2006.09.002 10.1016/j.chemer.2006.09.002 Search in Google Scholar

Namur, O., Charlier, B., Toplis, M.J., Higgins, M.D., Hounsell, V., Liégeois, J.P., Vander Auwera, J. (2011): Differentiation of tholeiitic basalt to A-type granite in the Sept Iles layered intrusion, Canada. Journal of Petrology, 52(3), pp. 487–539. Doi.org/10.1093/petrology/egq088 NamurO. CharlierB. ToplisM.J. HigginsM.D. HounsellV. LiégeoisJ.P. Vander AuweraJ. 2011 Differentiation of tholeiitic basalt to A-type granite in the Sept Iles layered intrusion, Canada Journal of Petrology 52 3 487 539 Doi.org/10.1093/petrology/egq088 10.1093/petrology/egq088 Search in Google Scholar

Zhou, G., Wu, Y., Wang, H., Qin, Z., Zhang, W., Zheng, J., Yang, S. (2017): Petrogenesis of the Huashanguan A-type granite complex and its implications for the early evolution of the Yangtze Block. Precambrian Research, 292, pp. 57–74. DOI.org/10.1016/j.precamres.2017.02.005 ZhouG. WuY. WangH. QinZ. ZhangW. ZhengJ. YangS. 2017 Petrogenesis of the Huashanguan A-type granite complex and its implications for the early evolution of the Yangtze Block Precambrian Research 292 57 74 DOI.org/10.1016/j.precamres.2017.02.005 10.1016/j.precamres.2017.02.005 Search in Google Scholar

Kerrick, D.M. (1969): K-feldspar megacrysts from a porphyritic quartz monzonite central Sierra Nevada, California. American Mineralogist: Journal of Earth and Planetary Materials, 54(5–6), pp. 839–848. KerrickD.M. 1969 K-feldspar megacrysts from a porphyritic quartz monzonite central Sierra Nevada, California American Mineralogist: Journal of Earth and Planetary Materials 54 5–6 839 848 Search in Google Scholar

Vernon, R.H. (1986): K-feldspar megacrysts in granites—phenocrysts, not porphyroblasts. Earth-Science Reviews, 23(1), pp. 1–63. Doi.org/10.1016/0012-8252(86)90003-6 VernonR.H. 1986 K-feldspar megacrysts in granites—phenocrysts, not porphyroblasts Earth-Science Reviews 23 1 1 63 Doi.org/10.1016/0012-8252(86)90003-6 10.1016/0012-8252(86)90003-6 Search in Google Scholar

Cox, R.A., Dempster, T.J., Bell, B.R., Rogers, G. (1996). Crystallization of the Shap Granite: Evidence from zoned K-feldspar megacrysts. Journal of the Geological Society, 153(4), pp. 625–635. Doi.org/10.1144/gsjgs.153.4.0625 CoxR.A. DempsterT.J. BellB.R. RogersG. 1996 Crystallization of the Shap Granite: Evidence from zoned K-feldspar megacrysts Journal of the Geological Society 153 4 625 635 Doi.org/10.1144/gsjgs.153.4.0625 10.1144/gsjgs.153.4.0625 Search in Google Scholar

Johnson, B.R., Glazner, A.F. (2010): Formation of K-feldspar megacrysts in granodioritic plutons by thermal cycling and late-stage textural coarsening. Contributions to Mineralogy and Petrology, 159(5), pp. 599–619. Doi.org/10.1007/s00410-009-0444-z JohnsonB.R. GlaznerA.F. 2010 Formation of K-feldspar megacrysts in granodioritic plutons by thermal cycling and late-stage textural coarsening Contributions to Mineralogy and Petrology 159 5 599 619 Doi.org/10.1007/s00410-009-0444-z 10.1007/s00410-009-0444-z Search in Google Scholar

Winter, J.D. (2001): An Introduction to Igneous and Metamorphic Petrology. Prentice Hall, Upper Saddle River, New Jersey, 699 pp. WinterJ.D. 2001 An Introduction to Igneous and Metamorphic Petrology Prentice Hall Upper Saddle River, New Jersey 699 pp Search in Google Scholar

Oyawoye, M.O. (1962): The petrology of the district around Bauchi, Northern Nigeria. The Journal of Geology, 70(5), pp. 604–615. Doi/abs/10.1086/626855 OyawoyeM.O. 1962 The petrology of the district around Bauchi, Northern Nigeria The Journal of Geology 70 5 604 615 Doi/abs/10.1086/626855 10.1086/626855 Search in Google Scholar

Oyawoye, M.O. (1967): The petrology of a potassic syenite and its associated biotite pyroxenite at Shaki, Western Nigeria. Contributions to Mineralogy and Petrology, 16(2), pp. 115–138. OyawoyeM.O. 1967 The petrology of a potassic syenite and its associated biotite pyroxenite at Shaki, Western Nigeria Contributions to Mineralogy and Petrology 16 2 115 138 10.1007/BF00372792 Search in Google Scholar

Dickson, F.W., Sabine, C.P. (1967): Barium zoned large K-feldspars in quartz monzonites of eastern and southeastern California [abs]. Geological Society of America Special Paper, 115, p. 323. DicksonF.W. SabineC.P. 1967 Barium zoned large K-feldspars in quartz monzonites of eastern and southeastern California [abs] Geological Society of America Special Paper 115 323 Search in Google Scholar

Oyawoye, M.O. (1972): The basement complex of Nigeria. African Geology, I. Ibadan University Press, Ibadan, pp. 67–99. OyawoyeM.O. 1972 The basement complex of Nigeria African Geology I. Ibadan University Press Ibadan 67 99 Search in Google Scholar

Johnson, B.R., Glazner, A.F., Coleman, D.S. (2006): Significance of K-feldspar megacryst size and distribution in the Tuolumne Intrusive Suite, California [abs.]. In: 102nd Annual Meeting of the Cordilleran Section, Geological Society of America: Abstracts with Programs; Vol. 38, No. 5, p. 93. JohnsonB.R. GlaznerA.F. ColemanD.S. 2006 Significance of K-feldspar megacryst size and distribution in the Tuolumne Intrusive Suite, California [abs.] In: 102nd Annual Meeting of the Cordilleran Section, Geological Society of America: Abstracts with Programs 38 5 93 Search in Google Scholar

Kennedy, W.Q. (1964): The structural differentiation of Africa in the Pan-African (+/−500 my) tectonic episode. University of Leeds, Research Institute of African Geology, Annual Report on Scientific Results; 8, pp. 48–49. KennedyW.Q. 1964 The structural differentiation of Africa in the Pan-African (+/−500 my) tectonic episode University of Leeds, Research Institute of African Geology, Annual Report on Scientific Results 8 48 49 Search in Google Scholar

Clifford, T.N. (1970): The Structural Framework of Africa. In: African Magmatism and Tectonics. Clifford, T.N., Gass, I.G. (eds.). Oliver and Boyd: Edinburgh, pp. 1–26. CliffordT.N. 1970 The Structural Framework of Africa In: African Magmatism and Tectonics CliffordT.N. GassI.G. (eds.). Oliver and Boyd Edinburgh 1 26 Search in Google Scholar

Van Breemen, O., Pidgeon, R.T., Bowden, P. (1977): Age and isotopic studies of some Pan-African granites from North-central Nigeria. Precambrian Research, 4(4), pp. 307–319. Doi.org/10.1016/0301-9268(77)90001-8 Van BreemenO. PidgeonR.T. BowdenP. 1977 Age and isotopic studies of some Pan-African granites from North-central Nigeria Precambrian Research 4 4 307 319 Doi.org/10.1016/0301-9268(77)90001-8 10.1016/0301-9268(77)90001-8 Search in Google Scholar

Ogezi, A.E.O. (1977): Geochemistry and geochronology of basement rocks from northwestern Nigeria. Ph. D. Thesis. University of Leeds, Department of Earth Sciences: Leeds, 298 pp. OgeziA.E.O. 1977 Geochemistry and geochronology of basement rocks from northwestern Nigeria Ph. D. Thesis. University of Leeds, Department of Earth Sciences Leeds 298 pp Search in Google Scholar

Grant, N.K. (1978): Structural distinction between a metasedimentary cover and an underlying basement in the 600-my-old Pan-African domain of northwestern Nigeria, West Africa. Geological Society of America Bulletin, 89(1), pp. 50–58. Doi.org/10.1130/0016-7606(1978)89%3C50:SDBAMC%3E2.0.CO;2 GrantN.K. 1978 Structural distinction between a metasedimentary cover and an underlying basement in the 600-my-old Pan-African domain of northwestern Nigeria, West Africa Geological Society of America Bulletin 89 1 50 58 Doi.org/10.1130/0016-7606(1978)89%3C50:SDBAMC%3E2.0.CO;2 10.1130/0016-7606(1978)89<50:SDBAMC>2.0.CO;2 Search in Google Scholar

Cahen, L., Snelling, N.J., Delhal, J., Vail, J.R., Bonhomme, M., Ledent, D. (1984): The West African Craton: The Guinea Rise. In: The Geochronology and Evo1ution of Africa, Cahen L., Snelling N.J., Delhal J., Vail J.R., et al. (eds.). Clarendon Press,;z Oxford, UK, pp. 296–311. CahenL. SnellingN.J. DelhalJ. VailJ.R. BonhommeM. LedentD. 1984 The West African Craton: The Guinea Rise In: The Geochronology and Evo1ution of Africa CahenL. SnellingN.J. DelhalJ. VailJ.R. (eds.). Clarendon Press Oxford, UK 296 311 Search in Google Scholar

Chappell, B.W. (1974): Two contrasting granite types. Pacific Geology, 8, pp. 173–174. ChappellB.W. 1974 Two contrasting granite types Pacific Geology 8 173 174 Search in Google Scholar

Pitcher, W.S. (1979a): The nature, ascent and emplacement of granitic magmas. Journal of the Geological Society, 136(6), pp. 627–662. Doi.org/10.1144/gsjgs.136.6.0627 PitcherW.S. 1979a The nature, ascent and emplacement of granitic magmas Journal of the Geological Society 136 6 627 662 Doi.org/10.1144/gsjgs.136.6.0627 10.1144/gsjgs.136.6.0627 Search in Google Scholar

[Pitcher, W.S. (1979b): Comments on the geological environments of granites. In: Origin of Granite Batholiths Geochemical Evidence, Atherton, M.P., Tarneyh, J. (eds.). Birkhäuser: Boston, pp. 1–8. Doi.org/10.1007/978-1-4684-0570-5_1 PitcherW.S. 1979b Comments on the geological environments of granites In: Origin of Granite Batholiths Geochemical Evidence AthertonM.P. TarneyhJ. (eds.). Birkhäuser Boston 1 8 Doi.org/10.1007/978-1-4684-0570-5_1 10.1007/978-1-4684-0570-5_1 Search in Google Scholar

Falconer, J.D. (1911): The Geology and Geography of Northern Nigeria. MacMillan: London, 295 pp. FalconerJ.D. 1911 The Geology and Geography of Northern Nigeria MacMillan London 295 pp 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 Publishing Company: Lagos, pp. 41–58. RahamanM.A. 1976 Review of the basement geology of Southwestern Nigeria In: Geology of Nigeria KogbeC.A. (ed.), Elizabethan Publishing Company Lagos 41 58 Search in Google Scholar

Hofmann, A.W. (1980): Diffusion in natural silicate melts: A critical review. Physics of Magmatic Processes, Hargraves, R.B. (ed.). Princeton University Press: Princeton, New Jersey, pp. 385–417. HofmannA.W. 1980 Diffusion in natural silicate melts: A critical review Physics of Magmatic Processes HargravesR.B. (ed.). Princeton University Press Princeton, New Jersey 385 417 10.1515/9781400854493.385 Search in Google Scholar

Hofmann, A.W., Hargraves, R.B. (2014): Diffusion in natural silicate melts: a critical review. In: Physics of Magmatic Processes, Hargraves, R.B. (ed.). Princeton University Press: Princeton, New Jersey, pp. 385–418. Doi.org/10.1515/9781400854493.385 HofmannA.W. HargravesR.B. 2014 Diffusion in natural silicate melts: a critical review In: Physics of Magmatic Processes HargravesR.B. (ed.). Princeton University Press Princeton, New Jersey 385 418 Doi.org/10.1515/9781400854493.385 10.1515/9781400854493.385 Search in Google Scholar

Williams, H., Turner, F.J., Gilbert, C.M. (1982): Petrography: An Introduction to the Study of Rocks in Thin Section. W. H. Freeman: San Francisco & Oxford, 626 pp. WilliamsH. TurnerF.J. GilbertC.M. 1982 Petrography: An Introduction to the Study of Rocks in Thin Section W. H. Freeman San Francisco & Oxford 626 pp Search in Google Scholar

Swanson, S.E. (1977): Relation of nucleation and crystal-growth rate to the development of granitic textures. American Mineralogist, 62(9–10), pp. 966–978. SwansonS.E. 1977 Relation of nucleation and crystal-growth rate to the development of granitic textures American Mineralogist 62 9–10 966 978 Search in Google Scholar

Paterson, S.R., Vernon, R.H., Zak, J. (2005): Mechanical instabilities and physical accumulation of K-feldspar megacrysts in granitic magma, Tuolumne Batholith, California, USA. The Journal of the Virtual Explorer, 18, pp. 1–18. Doi.org/10.3809/jvirtex.2005.00114 PatersonS.R. VernonR.H. ZakJ. 2005 Mechanical instabilities and physical accumulation of K-feldspar megacrysts in granitic magma, Tuolumne Batholith, California, USA The Journal of the Virtual Explorer 18 1 18 Doi.org/10.3809/jvirtex.2005.00114 10.3809/jvirtex.2005.00114 Search in Google Scholar

Moore, J.G., Sisson, T.W. (2008): Igneous phenocrystic origin of K-feldspar megacrysts in granitic rocks from the Sierra Nevada batholith. Geosphere, 4(2), pp. 387–400. Doi.org/10.1130/GES00146.1 MooreJ.G. SissonT.W. 2008 Igneous phenocrystic origin of K-feldspar megacrysts in granitic rocks from the Sierra Nevada batholith Geosphere 4 2 387 400 Doi.org/10.1130/GES00146.1 10.1130/GES00146.1 Search in Google Scholar

Trustwell, J.F., Cope, R.N. (1963): The Geology of Parts of Niger and Zaria Provinces. Northern Nigeria GSN Bulletin, 29, 53pp. TrustwellJ.F. CopeR.N. 1963 The Geology of Parts of Niger and Zaria Provinces Northern Nigeria GSN Bulletin 29 53pp Search in Google Scholar

Oyawoye, M.O. (1964): The geology of the Nigerian Basement Complex—a survey of our present knowledge of them. Journal of Mining Geology and Metal, 1(2), pp. 87–103. OyawoyeM.O. 1964 The geology of the Nigerian Basement Complex—a survey of our present knowledge of them Journal of Mining Geology and Metal 1 2 87 103 Search in Google Scholar

Tubosun, I.A., Lancelot, J.R., Rahaman, M.A., Ocan, O. (1984): U-Pb Pan-African ages of two charnockite-granite associations from southwestern Nigeria. Contributions to Mineralogy and Petrology, 88(1), pp. 188–195. Doi.org/10.1007/BF00371422 TubosunI.A. LancelotJ.R. RahamanM.A. OcanO. 1984 U-Pb Pan-African ages of two charnockite-granite associations from southwestern Nigeria Contributions to Mineralogy and Petrology 88 1 188 195 Doi.org/10.1007/BF00371422 10.1007/BF00371422 Search in Google Scholar

Paterson, S.R., Vernon, R.H., Tobisch, O.T. (1989): A review of criteria for the identification of magmatic and tectonic foliations in granitoids. Journal of Structural Geology, 11(3), pp. 349–363. Doi.org/10.1016/0191-8141(89)90074-6 PatersonS.R. VernonR.H. TobischO.T. 1989 A review of criteria for the identification of magmatic and tectonic foliations in granitoids Journal of Structural Geology 11 3 349 363 Doi.org/10.1016/0191-8141(89)90074-6 10.1016/0191-8141(89)90074-6 Search in Google Scholar

Vernon, R.H. (2000): Review of microstructural evidence of magmatic and solid-state flow. Visual Geosciences, 5(2), pp. 1–23. Doi.org/10.1007/s10069-000-0002-3 VernonR.H. 2000 Review of microstructural evidence of magmatic and solid-state flow Visual Geosciences 5 2 1 23 Doi.org/10.1007/s10069-000-0002-3 10.1007/s10069-000-0002-3 Search in Google Scholar

Paterson, S.R., Fowler Jr, T.K., Schmidt, K.L., Yoshinobu, A.S., Yuan, E.S., Miller, R.B. (1998): Interpreting magmatic fabric patterns in plutons. Lithos, 44(1–2), pp. 53–82. Doi.org/10.1016/S0024-4937(98)00022-X PatersonS.R. FowlerT.K.Jr SchmidtK.L. YoshinobuA.S. YuanE.S. MillerR.B. 1998 Interpreting magmatic fabric patterns in plutons Lithos 44 1–2 53 82 Doi.org/10.1016/S0024-4937(98)00022-X 10.1016/S0024-4937(98)00022-X Search in Google Scholar

Vernon, R.H. (1999): Quartz and feldspar microstructures in metamorphic rocks. Canadian Mineralogist, 37(2), pp. 513–524. VernonR.H. 1999 Quartz and feldspar microstructures in metamorphic rocks Canadian Mineralogist 37 2 513 524 Search in Google Scholar

Vernon, R.H. (2004): A Practical Guide to Rock Microstructure. Cambridge University Press: Cambridge, UK, 440 pp. VernonR.H. 2004 A Practical Guide to Rock Microstructure Cambridge University Press Cambridge, UK 440 pp 10.1017/CBO9780511807206 Search in Google Scholar

Vernon, R.H., Paterson, S.R. (2008): How late are K-feldspar megacrysts in granites? Lithos, 104(1–4), pp. 327–336. Doi.org/10.1016/j.lithos.2008.01.001 VernonR.H. PatersonS.R. 2008 How late are K-feldspar megacrysts in granites? Lithos 104 1–4 327 336 Doi.org/10.1016/j.lithos.2008.01.001 10.1016/j.lithos.2008.01.001 Search in Google Scholar

Tobisch, O.T., McNulty, B.A., Vernon, R.H. (1997): Microgranitoid enclave swarms in granitic plutons, central Sierra Nevada, California. Lithos, 40(2–4), pp. 321–339. Doi.org/10.1016/S0024-4937(97)00004-2 TobischO.T. McNultyB.A. VernonR.H. 1997 Microgranitoid enclave swarms in granitic plutons, central Sierra Nevada, California Lithos 40 2–4 321 339 Doi.org/10.1016/S0024-4937(97)00004-2 10.1016/S0024-4937(97)00004-2 Search in Google Scholar

Oziegbe, E.J., Ocan, O.O., Adebisi, A.P. (2020): Petrography and Microtextural Characteristics of Granodiorite from Wasimi, Southwestern Nigeria. Earth Sciences Malaysia (ESMY), 4(2), pp. 82–89. Doi.org/10.26480/esmy.02.2020.51.58 OziegbeE.J. OcanO.O. AdebisiA.P. 2020 Petrography and Microtextural Characteristics of Granodiorite from Wasimi, Southwestern Nigeria Earth Sciences Malaysia (ESMY) 4 2 82 89 Doi.org/10.26480/esmy.02.2020.51.58 10.26480/esmy.02.2020.82.89 Search in Google Scholar

Allaby, M. (2013): A Dictionary of Geology and Earth Sciences, 4th edition. Oxford University Press: Oxford, UK, 660 pp. AllabyM. 2013 A Dictionary of Geology and Earth Sciences 4th edition Oxford University Press Oxford, UK 660 pp Search in Google Scholar

Pandit, D. (2015): Geochemistry of feldspar intergrowth microtextures from paleoproterozoic granitoids in Central India: implications to exsolution processes in granitic system. Journal of the Geological Society of India, 85(2), pp. 163–182. Doi.org/10.1007/s12594-015-0204-9 PanditD. 2015 Geochemistry of feldspar intergrowth microtextures from paleoproterozoic granitoids in Central India: implications to exsolution processes in granitic system Journal of the Geological Society of India 85 2 163 182 Doi.org/10.1007/s12594-015-0204-9 10.1007/s12594-015-0204-9 Search in Google Scholar

Abart, R., Heuser, D., Habler, G. (2014): Mechanisms of myrmekite formation: case study from the Weinsberg granite, Moldanubian zone, Upper Austria. Contributions to Mineralogy and Petrology, 168(5), p. 1074. Doi.org/10.1007/s00410-014-1074-7 AbartR. HeuserD. HablerG. 2014 Mechanisms of myrmekite formation: case study from the Weinsberg granite, Moldanubian zone, Upper Austria Contributions to Mineralogy and Petrology 168 5 1074 Doi.org/10.1007/s00410-014-1074-7 10.1007/s00410-014-1074-7 Search in Google Scholar

Collins, L.G. (2003): Transition from magmatic to K-metasomatic processes in granodiorites and Pyramid Peak granite, Fallen Leaf Lake 15-Minute Quadrangle, California, USA. Myrmekite and Metasomatic Granite, ISSN 1526-5757, Internet publication, no. 48. CollinsL.G. 2003 Transition from magmatic to K-metasomatic processes in granodiorites and Pyramid Peak granite, Fallen Leaf Lake 15-Minute Quadrangle, California, USA Myrmekite and Metasomatic Granite ISSN 1526-5757, Internet publication, no. 48 Search in Google Scholar

Morad, S., El-Ghali, M.A.K., Caja, M.A., Sirat, M., Al-Ramadan, K., Mansurbeg, H. (2010): Hydrothermal alteration of plagioclase in granitic rocks from Proterozoic basement of SE Sweden. Geological Journal, 45, pp. 105–116. Doi.org/10.1002/gj.1178 MoradS. El-GhaliM.A.K. CajaM.A. SiratM. Al-RamadanK. MansurbegH. 2010 Hydrothermal alteration of plagioclase in granitic rocks from Proterozoic basement of SE Sweden Geological Journal 45 105 116 Doi.org/10.1002/gj.1178 10.1002/gj.1178 Search in Google Scholar

Cox, K.G. (2013): The Interpretation of Igneous Rocks. Springer Science & Business Media: New York, 450 pp. CoxK.G. 2013 The Interpretation of Igneous Rocks Springer Science & Business Media New York 450 pp Search in Google Scholar

Collins, L.G., Collins, B.J. (2013): Origin of myrmekite as it relates to K-, Na-, and Ca-metasomatism and the metasomatic origin of some granite masses where myrmekite occurs. Contribbutions to Mineralalogy and Petrology, 213, pp. 123–156. CollinsL.G. CollinsB.J. 2013 Origin of myrmekite as it relates to K-, Na-, and Ca-metasomatism and the metasomatic origin of some granite masses where myrmekite occurs Contribbutions to Mineralalogy and Petrology 213 123 156 Search in Google Scholar

Yund, R.A., McLaren, A.C. and Hobbs, B.E. (1974): Coarsening kinetics of the exsolution microstructure in alkali feldspar. Contributions to Mineralogy and Petrology, 48(1), pp. 45–55. Doi.org/10.1007/BF00399109 YundR.A. McLarenA.C. HobbsB.E. 1974 Coarsening kinetics of the exsolution microstructure in alkali feldspar Contributions to Mineralogy and Petrology 48 1 45 55 Doi.org/10.1007/BF00399109 10.1007/BF00399109 Search in Google Scholar

Yuguchi, T., Nishiyama, T. (2008): The mechanism of myrmekite formation deduced from steady-diffusion modeling based on petrography: Case study of the Okueyama granitic body, Kyushu, Japan. Lithos, 106(3–4), pp. 237–260. Doi.org/10.1016/j.lithos.2008.07.017 YuguchiT. NishiyamaT. 2008 The mechanism of myrmekite formation deduced from steady-diffusion modeling based on petrography: Case study of the Okueyama granitic body, Kyushu, Japan Lithos 106 3–4 237 260 Doi.org/10.1016/j.lithos.2008.07.017 10.1016/j.lithos.2008.07.017 Search in Google Scholar

Parsons, I., Lee, M.R. (2009): Mutual replacement reactions in alkali feldspars I: microtextures and mechanisms. Contributions to Mineralogy and Petrology, 157(5), pp. 641–661. Doi.org/10.1007/s00410-008-0355-4 ParsonsI. LeeM.R. 2009 Mutual replacement reactions in alkali feldspars I: microtextures and mechanisms Contributions to Mineralogy and Petrology 157 5 641 661 Doi.org/10.1007/s00410-008-0355-4 10.1007/s00410-008-0355-4 Search in Google Scholar

Parsons, I., Magee, C.W., Allen, C.M., Shelley, J.M.G., Lee, M.R. (2009): Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry. Contributions to Mineralogy and Petrology, 157(5), pp. 663–687. Doi.org/10.1007/s00410-008-0358-1 ParsonsI. MageeC.W. AllenC.M. ShelleyJ.M.G. LeeM.R. 2009 Mutual replacement reactions in alkali feldspars II: trace element partitioning and geothermometry Contributions to Mineralogy and Petrology 157 5 663 687 Doi.org/10.1007/s00410-008-0358-1 10.1007/s00410-008-0358-1 Search in Google Scholar

Parsons, I., Gerald, J.D.F., Lee, J.K., Ivanic, T., Golla-Schindler, U. (2010): Time–temperature evolution of microtextures and contained fluids in a plutonic alkali feldspar during heating. Contributions to Mineralogy and Petrology, 160(2), pp. 155–180. Doi.org/10.1007/s00410-009-0471-9 ParsonsI. GeraldJ.D.F. LeeJ.K. IvanicT. Golla-SchindlerU. 2010 Time–temperature evolution of microtextures and contained fluids in a plutonic alkali feldspar during heating Contributions to Mineralogy and Petrology 160 2 155 180 Doi.org/10.1007/s00410-009-0471-9 10.1007/s00410-009-0471-9 Search in Google Scholar

Vernon, R.H., Williams, V.A., D’arcy, W.F. (1983): Grain-size reduction and foliation development in a deformed granitoid batholith. Tectonophysics, 92(1–3), pp. 123–145. Doi.org/10.1016/0040-1951(83)90087-2 VernonR.H. WilliamsV.A. D’arcyW.F. 1983 Grain-size reduction and foliation development in a deformed granitoid batholith Tectonophysics 92 1–3 123 145 Doi.org/10.1016/0040-1951(83)90087-2 10.1016/0040-1951(83)90087-2 Search in Google Scholar

Harlov, D.E., Wirth, R. (2000): K-feldspar–quartz and K-feldspar–plagioclase phase boundary interactions in garnet–orthopyroxene gneiss's from the Val Strona di Omegna, Ivrea–Verbano Zone, northern Italy. Contributions to Mineralogy and Petrology, 140(2), pp. 148–162. Doi.org/10.1007/s004100000185 HarlovD.E. WirthR. 2000 K-feldspar–quartz and K-feldspar–plagioclase phase boundary interactions in garnet–orthopyroxene gneiss's from the Val Strona di Omegna, Ivrea–Verbano Zone, northern Italy Contributions to Mineralogy and Petrology 140 2 148 162 Doi.org/10.1007/s004100000185 10.1007/s004100000185 Search in Google Scholar

Yuguchi, T., Nishiyama, T. (2007): Cooling process of a granitic body deduced from the extents of exsolution and deuteric sub-solidus reactions: Case study of the Okueyama granitic body, Kyushu, Japan. Lithos, 97(3–4), pp. 395–421. Doi.org/10.1016/j.lithos.2007.01.005 YuguchiT. NishiyamaT. 2007 Cooling process of a granitic body deduced from the extents of exsolution and deuteric sub-solidus reactions: Case study of the Okueyama granitic body, Kyushu, Japan Lithos 97 3–4 395 421 Doi.org/10.1016/j.lithos.2007.01.005 10.1016/j.lithos.2007.01.005 Search in Google Scholar

Nanda, J., Gupta, S., Mamtani, M.A. (2009): Analysis of deformation fabric in an alkaline complex (Koraput): Implications for time relationship between emplacement, fabric development and regional tectonics. Journal of the Geological Society of India, 74(1), pp. 78–94. Doi.org/10.1007/s12594-009-0093-x NandaJ. GuptaS. MamtaniM.A. 2009 Analysis of deformation fabric in an alkaline complex (Koraput): Implications for time relationship between emplacement, fabric development and regional tectonics Journal of the Geological Society of India 74 1 78 94 Doi.org/10.1007/s12594-009-0093-x 10.1007/s12594-009-0093-x Search in Google Scholar

Yuguchi, T., Tsuruta, T., Nishiyama, T. (2011): Three-dimensional cooling pattern of a granitic pluton II: The study of deuteric sub-solidus reactions in the Toki granite, Central Japan. Journal of Mineralogical and Petrological Sciences, 106(3), pp. 130–141. Doi.org/10.2465/jmps.100129b YuguchiT. TsurutaT. NishiyamaT. 2011 Three-dimensional cooling pattern of a granitic pluton II: The study of deuteric sub-solidus reactions in the Toki granite, Central Japan Journal of Mineralogical and Petrological Sciences 106 3 130 141 Doi.org/10.2465/jmps.100129b 10.2465/jmps.100129b Search in Google Scholar

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