 | | Journal (article/letter/editorial) | | s Geochemistry and petrogenesis of the Fort Portal, Uganda, extrusive carbonatite G. Nelson Eby a,ā...Quaternary Fort Portal volcanic ļ¬eld occurs at the northern end of the Western Rift in Uganda. The eruptive...Quaternary Fort Portal volcanic ļ¬eld, is the subject of this paper. The Quaternary Fort Portal and Kasekere...Kasekere volcanic ļ¬elds of southwest Uganda (Fig. 1) were ļ¬rst mapped and described by von Knorring and Du...associated with the western branch of the East African rift system. Fort Portal and Kasekere are part |  | Bailey, Ken, Lloyd, Felicity, Kearns, Stuart, Stoppa, Francesco, Eby, Nelson, Woolley, Alan (2005) Melilitite at Fort Portal, Uganda: Another dimension to the carbonate volcanism. Lithos, 85 (1) 15-25 doi:10.1016/j.lithos.2005.03.019 | Journal (article/letter/editorial) | | elsevier.com/locate/lithos Melilitite at Fort Portal, Uganda: Another dimension to the carbonate volcanism...Abstract Because the calciocarbonatite lavas at Fort Portal were the first ever described they have received...contain melilitite previously unreported from Fort Portal. The rock is a mix of crust and mantle debris...through the enclosing rock matrix. Euhedral titano-magnetite (10ā15%) is the most obvious cognate mineral....crystals and microlites of melilite, apatite, magnetite, and carbonates, mostly formed during disequilibrium |  | | Journal (article/letter/editorial) | | known in the East African rift system in Kenya, Uganda, and Tanzania. Although some of these were studied...diatremes in the Fort Portal area; the Kavirondo ridge; and the Natron-Engaruka region. The rock samples...Carbonatites, ijolites, nephelinites, and phonolites Western rift: kivites, leucitites, and melanephelinites...cavities " " " Calcite and dolomite with magnetite, apatite, phlogopite, and pyroxene Same Composition...April 2015 Oldoinyo-L'Engai and Nyamlagira Fort Portal and Bunyaguru Kerimasi Kwaraha, Meru, and Hanang |  | | Journal (article/letter/editorial) | | High-Ca, low-alkali carbonatite volcanism at Fort Portal, Uganda Daniel S. Barker 1 and Peter H. Nixon 2 ...Abstract. A Quaternary volcanic field at Fort Portal, SW Uganda, contains approximately 50 vents that erupted...surround olivine, clinopyroxene and phlogopite, and magnetite is rimmed by spinel. The reaction relations suggest...the KatweKikorongo volcanic field 75 km SW of Fort Portal. The groundmass of fresh carbonatite lava consists...by crustal rock fragments and xenocrysts. At Fort Portal, eruption o f a C a O - M g O CO2-SiO 2 - P 2 |  | | Journal (article/letter/editorial) | | effusive magmatic association of Katwe-Kikorongo, SW Uganda F. E. Lloyd1;2 , A. R. Woolley3, F. Stoppa4 , and...melilitite-carbonatite tephra. Higher Al2O3 distinguishes Fort Portal carbonatite xenocrysts and some contain high...genesis of Katwe-Kikorongo olivine melilitite and Fort Portal carbonatite involves a 300 F. E. Lloyd et...kamafugite-carbonatite province of south west Uganda in the western branch of the East African Rift (Fig. 1)...1996). The effusive calcio-carbonatites of the Fort Portal Ā®eld lie 75 km to the north and are well documented |  | Campeny, Marc, Kamenetsky, Vadim S., Melgarejo, Joan C., Mangas, JosĆ©, Manuel, JosĆ©, Alfonso, Pura, Kamenetsky, Maya B., Bambi, Aurora C.J.M., GonƧalves, Antonio O. (2015) Carbonatitic lavas in Catanda (Kwanza Sul, Angola): Mineralogical and geochemical constraints on the parental melt. Lithos, 232. 1-11 doi:10.1016/j.lithos.2015.06.016 | Journal (article/letter/editorial) | | carbonatite lavas have been identified in this region and considering the mineralogical, textural and...magma from a study of melt inclusions hosted in magnetite microphenocrysts from all of these lavas. Melt...African Rift area (Woolley, 2001) such as Fort Portal, Uganda (von Knorring and Du Bois, 1961; Nixon and...carbonatite lavas located in the western African MA margin, are in a tectonic region affected by the break-up...mines in The volcanic activity in the Catanda region has never been precisely dated. Silva and Pereira |  | | Journal (article/letter/editorial) | | high-Mg ultrapotassic and carbonatite rocks in the western branch of the East African Rift Zone suggests the...composition of crystalline inclusions. In the Fort Portal volcanic field with separate carbonatite volcanoes...of olivine phenocrysts. Geological study of this region has been conducted since 1929 by Kombi and Holmes...from the southern slope of Kyambu Crater, on the western shore of Lake Mafuru (Fig. 1). The rocks are represented...The groundmass is built up of clinopyroxene, Ti-magnetite, perovskite, leucite, and kalsilite. There is |  | | Journal (article/letter/editorial) | | and uranpyrochlore from tuff near Ndale, Fort Portal area, Uganda D: D. HOGARTH Department of Geology, University...Recent, calcite-rich tuff at Ndale near Fort Portal, Uganda, unconformably overlies steeply dipping Precambrian...(4000-5000 yr) geological age. KEVWORDS: Fort Portal, Ndale, Uganda, tuff, pyrochlore, uranpyrochlore, uranium...mineralogists. Geological setting The area lies within the Western Rift of Africa (Fig. 1). The lower ground of the...H O G A R T H AND J. E. T. H O R N E I / t FORT PORTAL fo Kampolo surface is pitted by numerous volcanic |  | | Journal (article/letter/editorial) | | leucite-bearing assemblages of the Roman Comagmatic Region and represents the first reported occurrence of...belt, extending southwards through the Abruzzi region (Bosi and Locardi 1991) to Mount Vulture (Principe...stronger seismic activity, relative to the Roman Region (Lavecchia et al. 1994). The ULUD rock types represent...lavas of the adjacent, coeval Roman region, RRL (i.e. Roman region lavas; group III of Foley et al. 1987)...and carbonatite assemblages occurring in the Fort Portal volcanic field (Barker and Nixon 1989; Barker |  | | Journal (issue) | | Anniversary Geological Survey and Mines Department Uganda HER LONDON M AJESTY'S ST A TIO NER Y OFFIC...Commissioner of . . . Geological Survey and Mines, Uganda . . page INTRODUCTION. 1 GEOLOGICAL SURVEYS...Photogeology in the Mineral Exploration PrQgramme for Uganda. By J. E. N. Kagule-Magambo, BSc, MSc, DIC, . .... Geological Survey and Mines Department, Uganda . Follow-up Work and Interpretation of Reconnaissance...Karamoja,- Uganda. By P. W. G. Brock, BASc, PhD, formerly Geological Survey and Mines Department, Uganda . . |  | | Journal (article/letter/editorial) | | 23% Fe-monticellite, 9% Th-perovskite plus Ti-magnetite, 6% Cr-phlogopite, 6% forsteritic olivine, about...Ultraalkaline District has been observed only in the western branch of the Eastern African Rift and in the southern...sanidine, leucite, analcime, titanite and Ti-magnetite surround the Polino diatremes. 39Ar/4Ā°Ar radiometric...groundmass, where it occurs together with Ti-magnetite as small subhedral crystals or as fine-grained...Th-perovskite is not easily distinguished from Ti-magnetite; Zr-schorlomite is easily recognisable by its |  | | Journal (article/letter/editorial) | | Tamazert, Morocco Fort Portal, Uganda Katwe-Kikorongo, Uganda Bunyaraguru, Uganda Tinderet, Kenya C...large volcanoes or SVEs. An exception is the Fort Portal occurrence which comprises numerous carbonatitic...mantle origin. The identification of some of the Fort Portal carbonatitic tuffs as ignimbrites (Barker and...appear to be unique to that volcano, whilst the Fort Portal lava and lava bombs are apparently also unique...Morocco Fort Portal, Uganda Katwe-Kikorongo, Uganda SVE SVE V SVE SVE SVE 25 Bunyaraguru, Uganda SVE |  | | Journal (article/letter/editorial) | | June 2002, Vol. 66(3), pp. 379ā384 High-Ti magnetite in some fine-grained carbonatites and the magmatic...Queenās Road, Bristol BS8 1RJ, UK ABSTR ACT Magnetite is present in most carbonatites, and in the most...are seen. Checks on similar rocks from Germany, Uganda and Tanzania reveal magnetites with comparable...volcanic rocks cover only parts of this array. Magnetite analyses from some other fine-grained carbonatites...coarse-grained intrusive carbonatites, in which the magnetite compositions are attributed to slow cooling, with |  | Neave, David A., Black, Martin, Riley, Teal R., Gibson, Sally A., Ferrier, Graham, Wall, Frances, Broom-Fendley, Sam (2016) On the Feasibility of Imaging Carbonatite-Hosted Rare Earth Element Deposits Using Remote Sensing. Economic Geology, 111 (3) 641-665 doi:10.2113/econgeo.111.3.641 | Journal (article/letter/editorial) | | Phlogopite 3 20 37 BastnƤsite-(Ce) Monazite-(Ce) Magnetite 9 5 500 1000 1500 2000 Wavelength (nm) 10%...Uyaynah in the United Arab Emirates, and Fort Portal in Uganda. Carbonatites from the following locations...Africa. Carbonatites from Tororo and Sukulu in Uganda, Chilwa Island and 643 Kangankunde in Malawi...calcite, Fl = fluorite, Haung = huanghoite, Mag = magnetite, Mz = monazite, Par = parasite, Phl = phlogopite...carbonatite melt (Mariano, 1989). Mount Weld in Western Australia started processing ore in 2011 and is |  | | Journal (article/letter/editorial) | | that of the carbonate rocks associated with the Western Rift volcanism ( -5.8 to -7*90/,). In contrast...eastern belt along the Uganda-Kenya border, and a western one along the Uganda-Congo border associated...associated with the Western Rift system. Three carbonatites from the eastern, north-south trending belt were sampled:...kimberlite carbonates of carbonatites from Ea&ern Uganda &P 6018 PZB SMZV Tororo (All samples from...soda-pyroxene eovite c.g. monticellite-magnetite sovite 0.g. montioellite-magnetite sovite c.g. sodepyroxene-biotite |  | | Journal (article/letter/editorial) | | among others. Fresh carbonatite lavas at Fort Portal, Uganda (Barker and Nixon 1989), and Oldoinyo Lengai...Ti, Fe, Mn, Mg, and P (as 0.5% perovskite, 6% magnetite, 10.5% apatite, 7% dolomite) and 30% calcite can...carbonatite dike at Fort Portal, Uganda (Barker and Nixon 1989). Other Fort Portal carbonatite samples...clinopyroxene, and phlogopite. Groundmass periclase in Fort Portal and Kerimasi (Mariano and Roeder 1983) carbonatite...single thin sections of carbonatites (apatite and magnetite are also present in most assemblages). 1 Upper |  | | Journal (article/letter/editorial) | | Wasaki carbonatite intrusion near Homa Bay in western Kenya, could also be interpreted to bear a similar...genetically related to normal carbonatites (e.g. those of Uganda and Scandinavia) as advocated by Heinrich (1967)...flank of Homa Mountain carbonatite complex in western Kenya (Le Bas, 1977). Carbonatitic tufts and agglomerates...lavas have been described from the Fort Portal area in western Uganda (von Knorring and Du Bois, 1961)...or more of the minerals apatite, phlogopite, magnetite, aegirine, aegirine-augite, and pyrochlore are |  | | Journal (article/letter/editorial) | | apatite-forsterite-magnetite rocks is cut by veins of calcitic carbonatites. The apatite-forsterite-magnetite rocks...clasts may include pyroxenites, ijolites, apatite-magnetite rocks, carbonatites, and other rocks, all a t...frequently. The accessory mine r a l s a r e magnetite and perovskite. Among the mineral phenocrysts...pyroxene (and sometimes amphibole), apatite, magnetite, and accessory perovskite, baddeleyite, and sometimes...albite, and quartz; the o r e minerals consist of magnetite, ilmenite, and pyrite. In some of the dikes, the |  | | Journal (article/letter/editorial) | | calcite with a small amount of clay, apatite, and magnetite. The SrO contents of phenocrysts, microphenocrysts...are found in and near several volcanoes of the western Kenya alkalic volcanic province (LeBas 1977). Calcitic...calcitic carbonatite lavas have been found in western Uganda (Knorring and Dubois 1961 ; Nixon and Hornung...all Mg is present as carbonate except in the magnetite. Calcite was used as the probe standard for Ca...oxide. Other minerals in the residue are apatite, magnetite, and augite, in order of decreasing abundance |  | | Journal (article/letter/editorial) | | Cupaello. The principal carbonatitic tufts lie at the western end of the lava flow, south-southeast of Cupaello...Zr-schorlomite (Lupini et al., 1992), apatite and Ti-magnetite set in a cryptocrystalline calcite matrix. The...phenocrysts. Total diameter of lapillus about 1 cm Ti-magnetite. There are abundant amoeboid vesicles, up to 1...groundmass), monticellite 23%, Th-perovskite plus Ti-magnetite 9%, olivine 6%, phlogopite 6%, Zr-schorlomite...groundmass of calcite, apatite, clinopyroxene, magnetite, schorlomite and perovskite. Larger pyroxene and |  | | Report (chapter) | | represent the final residua expelled from the source region. Most large carbonatite intrusions seem to have...(Lengai) 2. Calcio-c (Kerimasi) 3. Calcio-c (Ft. Portal) 4. Calcio-c (Polino) 5. Calcio-c (Kaiserstuhl)...by 1961 the Recent carbonatite lava flow at Fort Portal had been described (von Knorring & Du Bois 1961)...tufts cemented by calcium carbonate. In the Fort Portal lava flow, olivine, diopside and phlogopite xenocrysts...Calcio-carbonatites 1. Ft Portal Cc, Cs, P, Ap, Mo O1, Di, Phi, Per, Ap (Uganda) 2. Catanda Carbonates. |  | | Journal (article/letter/editorial) | | nephelinite-carbonatite volcano, Homa Bay District, western Kenya (0Āŗ34āS; 34Āŗ09āE) contains carbonatitic lapilli...compositions at Rangwa. Other key minerals are magnetite, two types of mica (magnesian-biotite phenocrysts...calcite, aegirine and diopside, fluorapatite, magnetite, plus some phlogopite, titanite, K-feldspar, fenite...crystallization of calcite, phlogopite, apatite and magnetite. Preservation of the the potassic component may...form of carbonatite volcanism and nephelinites in western Kenya, as described by Le Bas (1977). The samples |  | | Journal (article/letter/editorial) | | NGITE 773 Frc. 1. Sketch map of part of the Western Rift Vatley of Africa showing the horst of Ruwenzori...Ruwenzori, in and adjoining the 774 ARTHUR HOLMES Western Rift of Central Africa, there are several areas... George depressiondies out to the north (h) Fort Portal, where the eastern wall of the L. Albert rift...reconnaissance collections made in the early days of the Uganda Survey. Subsequently my old friend and collaborator...names of the craters: e.g. Kasesankaranga(in the Fort Portal area) means ,,spewer of roasted material." The |  | | Journal (article/letter/editorial) | | All rights reserved. The Western Branch of the East African Rift is a region with classic occurrences...the volcanic rocks within a limited geographic region is a reļ¬ection of upper mantle heterogeneity at...Virunga provinces in the northern part of the Western Branch of the East African Rift (Fig. 1). Sr, Nd...from Napak and Mount Elgon volcanoes, eastern Uganda-western Kenya (Simonetti and Bell, 1993, 1995). The...magmatism in the Western Branch of the East African Rift. Geological study of this region was ļ¬rst conducted |  | | Journal (article/letter/editorial) | | outcrop occurs about 7 km to the east Spoleto, Umbria region, and covers an area of 10,000 m2, including a large...Panina et al. Fig. 1 Š° the geological map of Umbria region (central Italy) showing main geological and geographical...together with accessory Ti-garnet, Ti-clinopyroxene, magnetite, perovskite, rankinite, apatite, Fe-Ni-sulfides...acicular aggregates of clinopyroxene, ore phases (magnetite, sulfides), and glass (Stoppa and Rosatelli 2009)...minor amount (5 vol.%) of Ti-garnet, apatite, magnetite and Fe-Ni-sulfides (Fig. 2a). According to IUGS |
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