| | Journal (article/letter/editorial) | VALLEY ALBITE-RIEBECKITEGRANITE, LIRUEI GRANITE RING-COMPLEX, NORTHERN NIGERIA I.P. ORAJAKA Department of Geological...Anambra State University of Technology, Enugu (Nigeria) (Received November 20, 1985; accepted for publication...albite--riebeckite-granite, Liruei Granite ring-complex, northern Nigeria. Chem. Geol., 56 : 85--92. The...The granite contains abundant rounded grains of quartz and numerous small prisms of riebeckite set in...1. Introduction The Chad Basin of northeastern Nigeria has recently been the focus of intense exploration | | | Journal (article/letter/editorial) | Rossesring complex, County Donegal, Ireland. The beryl occursin patchesof greisen,in quartz veinsand pegmatites...haveformedat a late stagein the development of the ring complex. Guidedby this interpretation,the distributionand...Newer Caledonian (post-Dalradian, pre-Carboniferous) ring complexthat intrudesmigmatitic granodiorite in north-west...granite(G1), whichissucceeded by an intermediate ring oœcoarse-grained granite(G2), followed in turn by...granodiorite; G1-G4:granite typesin theRosses ring complex(nmscovite-rich G3 graniteshownstippled);B: beryl | | | Book | Distribution in Tin-bearing Pegmatites of Southwestern Nigeria. . . . . . . G. Matheis, W.O. Emofurieta and S...Department of Geology, University of Ife, Ile-Ife, Nigeria B.J. FRYER Department of Geology, Memorial University...Nigerian Steel Development Authority, Kaduna, Nigeria OHIWEREJ List of Contributors IX B. VAN DE...fractures which have served to guide the processes of quartz-tourmaline and greisen alteration in the consolidated...trending elvan dyke which also cuts the tourmaline-quartz-greisen fracture sets (Fig. 4). Dangerfield et | | | Book (volume) | allocated on a structural basis: vol. 1. Ortho- and Ring Silicates, vol. 2. Chain Silicates, vol. 3. Sheet...illustrate the six polymorphs as in Fig. 4. Many more complex cells are possible and the existence of some of...— ' 3-112 j[■3-11 6. Emerald-green fuchsite, quartz conglomerate in staurolite zone of metamorphism...subtracting 7 per cent, siliimanite, and 2 per cent, quartz). Muscovite 19 When muscovite is decomposed...equilibrium curve for the reaction muscovite + quartz^ potassium felspar + sillimanite 4- vapour, which | | | Book (edition) | Petrography Continental Basaltic Associations Plateau Basalts • Local Basalt Fields Chapter 4 4.1 Field...Overall. energy is conserved. but its flow is complex. Immediately before impact, the total energy is...and/or to transform to denser phases (for example. quartz - coesite stishovite). This qualitative example...chemical equilibrium. Many geologic systems are so complex (varying significantly in both space and time)...rock. Suppose a particular rock is comprised of quartz, feldspar, and biotite (see Figure 1-4). Whether | | | Report (issue) | increasingly been directed towards areas of more complex geology, so that the actual mapping takes longer...project. In west Wales, owing to rugged terrain and complex Lower Palaeozoic geology, progress with the primary...00-ft) Terrace of the Thames and by re-sorted Plateau Gravels. Dr. Hamblin has mapped gravels of the...tuffs. The tuffs are disconformably overlain by quartz sandstones containing fine-grained igneous fragments...overlain in turn by the Upper Rhyolite Group, a complex of tuffi.tes consisting of coarse tuff fragments |
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